Dissertations / Theses on the topic 'Reversed sexual size dimorphism'

This project describes various aspects of the breeding ecology and behaviour of the brown falcon Falco berigora, a common but poorly study Australian raptor. In particular it examines (a) the main influences on reproductive success; (b) tests predictions of theories proposed to explain the evolution and maintenance of sexual size dimorphism (RSD; females the larger sex) in raptors; and (c) investigates sex allocation patterns in the light of current sex ratio and parental investment theory. The study was conducted between July 1999 and June 2002 approximately 35 km southwest of Melbourne, at the Western Treatment Plant (WTP), Werribee (38°0’S 144°34’E) and surrounds, a total area of approximately 150 km2.¶ · In all plumage and bare part colouration of 160 free-flying falcons was described. The majority of variation in these characters could be attributed to distinct age and/or sex differences as opposed to previously described colour ‘morphs’.¶ · Nestling chronology and development is described and formulae based on wing length derived for determining nestling age. An accurate field-based test for determining nestling sex at banding age is also presented.¶ · Strong sex role differentiation was apparent during breeding; typical of falcons females performed most parental duties whilst males predominantly hunted for their brood and partner. Based on observations of marked individuals, both sexes of brown falcons aggressively defended mutual territories throughout the year, with just 10% of each sex changing territories during the entire study period. Males performed territorial displays more frequently than females, the latter rarely displaying alone.¶ · The diet of the population as a whole was very broad, but within pairs both sexes predominantly specialised on either lagomorphs, small ground prey (e.g. house mice Mus musculus), small birds, large birds or reptiles, according to availability.¶ · Reproductive parameters such as clutch size and the duration of parental care were constant across all years, however marked annual differences in brood size and the proportion of pairs breeding were evident.¶ · Age was an important influence upon reproductive success and survival, with immature birds inferior to adults in both areas. However, interannual differences were by far the most influential factor on breeding success and female survival. Heavy rain downpours were implicated as the main determinant of reproductive success and adult female mortality in a population largely devoid of predation or human interference.¶ · Female-female competition for territorial vacancies was intense; larger adult females were more likely to be recruited and once breeding fledged more offspring. In contrast, male recruitment and breeding success was unrelated to either body size or condition indices, although smaller immature males were more likely to survive to the next breeding season. This directional selection is consistent only with the predictions of the intrasexual competition hypothesis.¶ · Despite marked RSD (males c. 75% of female body mass), throughout the nestling phase female nestlings did not require greater quantities of food than their male siblings. However, female parents fed their last-hatched sons but not daughters, resulting in the complete mortality of all last-hatched female offspring in focal nests. Given last-hatched nestlings suffered markedly reduced growth rates and female, but not male, body size is important in determining recruitment patterns, the biased allocation amongst last-hatched offspring is likely to reflect differing benefits associated with investing in small members of each sex, consistent with broad-scale Trivers-Willard effects. Recruitment patterns support this, with surviving last-hatched females, in contrast to males, unable to gain recruitment into the breeding population upon their return to the study site.¶ Thus selection appears to act at the nestling, immature and adult stages to maintain RSD in the focal population. Larger females were favoured in the nestling phase, at recruitment and once breeding had greater reproductive success. In contrast, selection favoured a reduction or maintenance of immature male size as smaller birds had a greater chance of survival in the year following recruitment than their larger counterparts; thereafter male size was unimportant. Together, this directional selection favouring increased female competitive ability is consistent only with the predictions of the intrasexual competition hypothesis, which appears the most probable in explaining the maintenance and perhaps evolution of RSD in raptors.

Individual differences within populations in a range of phenotypic traits are hypothesised to have important ecological and evolutionary implications. Variation in individual growth rates that result in corresponding variations in body sizes, including size dimorphism, is a particularly widespread feature of many animal populations. The increasing characterisation of consistent individual behavioural variations, unrelated to age or sex, is equally considered to have important fitness consequences. Our understanding of behavioural causes of size dimorphism remains weak, and few studies have investigated the relationship between individual behavioural consistency and growth variations in size dimorphic populations. The overall aim of this thesis is to identify the behavioural drivers that underpin observed growth variations and result in size dimorphism by using pike (Esox lucius) as a model species. The results show that early life growth is an important driver of sexual size dimorphism in this species. A subsequent focus on the juvenile life stages revealed that individual differences in movement and dispersal tendencies were related to growth and body size in wild pike. The findings indicate that intraspecific interactions such as size-dependent interference competition during the first year of life plays a key role in maintaining intraspecific size variation and size dimorphism in the wild population. Experimental work revealed the occurrence of a behavioural syndrome, where the rank order differences in the foraging behaviour between individuals were maintained across time and risk situation. This suggests that individual competitive ability is underpinned by a variation in boldness to forage under risk. The importance of a heterogeneous environment and presence of intraspecific competition pressure for driving habitat and resource segregation, and subsequently sexual size dimorphism, is discussed.

By performing a comparative analysis and using phylogenetic relationships of the Cervidaefamily this study aimed to address whether or not sexual selection may play a role in the extinctionof species by making species more vulnerable to extinction. The role of sexual selection in makingspecies more vulnerable to extinction is largely unexplored, and several factors such as ecologicaland life history traits may increase the risk of extinction.In all species of the family Cervidae (Gilbert et al. 2006, Geist 1998,Groves and Grubb2011,Meijaardand Groves2004,Price et al. 2005, Goss 1983) sexually selected characters plays amain role in determining species status and thus potentially their probability of extinction. In thisstudy the intensity of sexual selection (measured as sexual size dimorphism, antler size and matingsystem) and the rate of extinction (IUCN classification and anthropogenic effect) were counted asfactors to determine the role of sexual selection intensity in both species-rich and species-poorclades.By using the programme MESQUITE and phylogenetic trees, the results show an associationbetween species with larger body size and dimorphism, living in open habitats and having largerantler size expanded to more than three tines; such species are mostly non-territorial and formharems during the rutting season. The small species are territorial, live in closed habitats, aremonomorphic and have small antler size limited to two tines or less. Moreover species that aremore subjected to habitat degradation and anthropogenic effects tend to become smaller in size.Extinction risk for the species-rich clades with small sized, territorial and small antler sizedspecies is lower than for those consisting of species with larger antler size, larger body size, livingin open habitats and using harems as mating system.To sum up, the intensity of sexual selection in larger species in deer family put them in risk ofextinction; but on the other site, small species are more adapted to the environment by choosingdifferent strategy in mating system, and reducing antler and body size thus diminishing theextinction risk.

Thesis (MSc)--Stellenbosch University, 2001.
ENGLISH ABSTRACT: PELOMEDUSA SUBRUFA is a freshwater turtle widely distributed throughout Africa and Madagascar, and is described as a Tropical to Sub-tropical species. 1 examined the female and male reproductive cycles of P. subrufa, over a 20-month period to determine whether they display a typical Tropical to Sub-tropical type reproductive cycle (pre-nuptial) or a typical Temperate Zone type reproductive cycle (post-nuptial). Blood and tissue samples were collected from wild specimens captured in the Western Cape, South Africa and these samples were supplemented by tissue samples obtained from museum specimens. In female P. subrufa seasonal variation in related circulating reproductive hormones in the plasma (estradiol, progesterone, and testosterone) were analyzed using validated ELISA kits. Plasma vitellogenin (yolk precursor produced in liver) was measured using a newly developed universal vitellogenin ELISA for vertebrates (UNIVTG). Ovarian follicles were measured (± 0.1 mm) and female ovaries were staged macroscopically (non-active, pre-vitellogenic, vitellogenic, gravid), and results were confirmed via histological sectioning of ovaries and oviducts. Females exhibited a cyclic reproductive pattern, with distinct phases of follicular enlargement (vitellogenesis), ovulation and a gravid period. Seasonal timing of the reproductive cycle coincided with those of other temperate zone freshwater turtles. Vitellogenic recrudescence began in summer (late December), and continued unabated through winter with ovulation occurring in the following spring (September-October). My data suggested that P. subrufa females mostly lay a single clutch of eggs during the late-spnng summer period (September through January). Clutch size varied between 7 -3 7 eggs, with the number of eggs being significantly correlated with maternal body size (r = 0.82, P < 0 001). Plasma estradiol and plasma vitellogenin concentrations peaked once during the ovarian cycle, typically coinciding with the period of early- to mid-vitellogenesis in late summer. Plasma testosterone varied throughout the year, but significant increases were measured during the ovulation and mating period in spring. Plasma progesterone concentrations were significantly elevated during the gestation period prior to ovi-position in mid-summer (December). In male P. subrufa spermatogenesis in mature specimens was distinctly seasonal and timing of the reproductive cycle coincided with those of other temperate zone freshwater turtles. Spermatogemc recrudescence began in summer, following emergence from a winter hibernation period (brumation) and spring mating. Peak testicular volume and maximum spermiogemc activity occurred in late summer and early autumn. Testicular regression commenced in autumn through winter. Spermatozoa were abundant in the ducti epididymi throughout the year. Plasma testosterone concentrations peaked once during the testicular cycle, typically coinciding with spermio genes is in late summer, early autumn. Ducti epididymi diameter showed significant variation throughout the year, whereas the epithelial cell height showed no significant seasonal variation. Peak secretory activity coincided with spermiogemc activity and high circulating testosterone concentrations in late summer, early autumn. Testicular recrudescence was correlated with increasing ambient air temperatures, photopenod and summer rainfall, whereas testicular regression, during late autumn, corresponded conversely with decreasing ambient air temperatures, photopenod and rainfall. Female and male reproductive cycles were asynchronous in that the peak spermatogenic activity occurred in autumn at the time when most females were depositing yolk in growing ovarian follicles. Therefore, adult females displayed a typical postnuptial vitellogemc cycle and adult males displayed a typical post-nuptial spermatogenic cycle. Differences between sexes in body size are common in many animals, and the African helmeted turtle is no exception. Sexual size dimorphism (SSD) in P. subrufa was pronounced, and using principal component analysis, it was clear that adult male P. subrufa was significantly larger than adult females. Using carapace length as the measure of body size (covariate), adult males, adult females, and juveniles differed significantly in absolute size of the carapace width, carapace depth, plastron length, plastron width, and head depth. However, there was no significant difference between adult males, adult females and juveniles in head width and head length. Therefore, adult males were larger than adult females in the seven traits measured, except in carapace depth where the females were significantly larger In the occurrence of ontogenetic growth patterns, the adults grow at a slower rate than juveniles in plastron length. There was no significant difference between adults and juveniles in shell width, however in depth, the adults grow at a faster rate when compared to the juveniles. Adults significantly grow at a faster rate than juveniles in absolute head size as well. However, when these traits were used as a whole data set (eight traits measured), there was no difference in growth rate between adults of either sex. Similarly, there was no significant difference in adults compared to juveniles in shell size, however, adults grow at a faster rate than juveniles in absolute body size and head size. Differences in body size, and in the size of traits such as shell measurements and head measurements relative to absolute body size, were assessed to clarify SSD of P. subrufa in South Africa.
AFRIKAANSE OPSOMMING: PELOMEDUSA SUBRUFA is ‘n varswaterskilpad wat wyd verspreid oor Afrika en Madagascar voorkom en word beskryf as ‘n Tropiese tot Sub-tropiese spesies. Die manlike en vroulike voortplantingspatroon van P. subrufa is oor ‘n tydperk van 20 maande bestudeer om vas te stel of hul voortplanting ooreenstem met ‘n tipiese tropiesie tot sub-tropiese voortplantingspatroon of ‘n tipiese gematigde-sone voortplantingspatroon. Waterskilpaaie is uit damme in die Wes-Kaap, Suid-Afnka gevang en bloed- en weefselmonsters is versamel. Materiaal en data is aangevul deur weefselmonsters van waterskilpaaie wat in museumversamelings gehuisves word. Ovarium follikels in P. subrufa wyfies is gemeet en die wyfies se ovanums is makroskopies gegradeer (onaktief, pre-vitellogenies, vitellogemes, dragtig) en resultate is deur histologiese snitte van die ovaria en ovidukte bevestig. Wyfies vertoon ‘n sikliese voortplantingspatroon, met duidelike fases van follikulere groei (vetllogenese), ovulasie en dragtigheid. Sirkulerende voortplantingshormone in die bloedplasma (estradiol, progesteroon en testosteroon) is ook geanaliseer met behulp van gevalideerde hormoonspesifieke ELISA bepalings. Plasma vitellogeen (‘n dooiervoorloper wat in die lewer vervaardig word) konsentrasies is ook bepaal met ‘n nuut ontwikkelde, universele (spesifiek vir werweldiere) vitellogeen ELISA (UNIVTG). Seisoenale tydsberekemng van die voortplantingsiklus het ooreengestem met die van ander varswaterskilpaaie vanuit die Gemagtigde-sone. Vitellogenese het in die somer begin en duur voort deur die grootste gedeelte van die somer, herfs en winter gevolg deur ovulasie in die daaropvolgende lente (September - Oktober). Die data ingewin stel voor d a t/5. subrufa wyfies meestal een broeisel eiers tydens laat lente-somer le (September tot Januane). Broeiselgrootte het gewissel tussen 7-37 eiers, met die hoeveelheid eiers wat beduidend met moederlike liggaamsgrootte gekorreleer was (r = 0.82, P < 0.001). Plasma estradiol en vitellogeen konsentrasies het een keer tydens die ovariumsiklus gepiek, en gewoonlik saamgeval met vroee tot middel vitellogenese in die laat somer. Plasma testosteroon het dwarsdeur die jaar gevarieer, maar beduidende toenames is gemeet tydens ovulasie en die paartydperk in die lente. Plasma progesteroon konsentrasies was beduidend hoer tydens dragtigheid kort voor eierlegging in die middel van die somer (Desember). In volwasse P. subrufa mannetjies was spermatogenese sterk seisoenaal en het die voortplantingsiklus ooreengestem met die van ander varswaterskilpadspesies wat in die gematigde streke voorkom. Na ‘n oorwinteringsperiode (brumasie), volg die panngstydperk gedurende die lente. ‘n Nuwe spermatogemese siklus het in die somer begin. Maksimale spermatogeniese aktiwiteit en testis-volume word in die laat somer en vroee herfs bereik. Testikulere regressie neem in aanvang in die herfs en duur voort tot na paringstyd in die lente. Tydens testikulere regressie word spermatosoe in die ducti epididymi gestoor. Plasma testosteroon konsentrasies het in die laat somer en vroee herfs gedurende die testikulere siklus, spermiogenese (sperm produksie fase), gepiek. Die grootte (omtrek) van die ducti epididymi het beduidende vanasie dwarsdeur die jaar getoon, terwyl epiteel selhoogtes geen beduidende seisoenale vanasie getoon het nie. Piek sekretonese aktiwiteit het saamgeval met spermiogeniese aktiwiteit en hoe vlakke van sirkulerende testosteroon tydens laat somer en vroee herfs. Testikulere groei het goed gekorreleer met toenemende omgewingstemperatuur, fotopenode en reenval, terwyl testikulere regressie in herfs met ‘n daling in omgewingstemperature, fotopenode en reenval gekorrespondeer het. Die vroulike en manlike voortplantingspatrone was nie goed ge-sinkroniseerd nie, deurdat piek spermatogeniese aktiwiteit tydens herfs voorgekom het, gedurende die tyd waann meeste wyfies besig was om dooier in groeiende ovarium follikels neer te le. Daarteenoor vertoon die mannetjies testikulere regressie tydens die pre-ovulatoriese fase en ovulasie penode van die wyfies. Dus toon volwasse wyfies ‘n tipiese gematigde sone vitellogeniese patron en volwasse mannetjies ‘n tipiese gematigde sone spermatogeniese patroon. ‘n Verskil in liggaamsgrootte tussen die geslagte is 'n algemene verskynsel by baie diere en P. subrufa is geen uitsondering me. Daar was wesenlike geslagtelike grootteverskille (SSD) in P. subrufa en ‘n hoofkomponent analise (PC A) het getoon dat daar beduidende morfometnese verskille tussen volwasse mannetjies en wyfies was. Deur karapakslengte as 'n maatstaf vir liggaamsgrootte te gebruik (mede-veranderlike), het volwasse mannetjies, volwasse wyfies en onvolwassenes beduidend verskil ten opsigte van absolute grootte van hul karapaksbreedte, karapaksdiepte, plastronlengte, plastronbreedte en kopdiepte. Geen beduidende verskil in kopbreedte en koplengte in volwasse mannetjies, volwasse wyfies en onvolwassenes is gevind nie. Derhalwe was volwasse mannetjies groter as volwasse wyfies in sewe van die liggaamseienskappe wat gemeet is, buiten vir karapaksdiepte waar die wyfies beduidend groter was. In terme van die voorkoms van ontogenetiese groeipatrone het volwassenes teen ‘n stadiger tempo as onvolwassenes in plastronlengte toegeneem. Daar was geen beduidende verskil in die groeitempo van dopbreedte tussen volwassenes en onvolwassenes nie, alhoewel dopdiepte van volwassenes teen ‘n vinniger tempo gegroei het as die van onvolwassenes. Absolute kopgrootte van volwassenes het ook teen ‘n vinniger tempo gegroei as in onvolwassenes. Wanneer hierdie eienskappe as ‘n volledige datastel gebruik word (al agt gemete eienskappe), wil dit voorkom asof daar geen verskil in groeitempo van volwassenes van die onderskeidelike geslagte is me. Daar was geen beduidende verskil tussen volwassenes en onvolwassenes, ten opsigte van dopgrootte nie, alhoewel volwassenes klaarblyklik teen ‘n vinniger tempo in liggaamsgrootte en kopgrootte toeneem. Verskille in liggaamsgrootte en grootte van ander veranderlikes, soos byvoorbeeld dop- en kop-eienskappe, relatief tot absolute liggaamsgrootte, word aangebied om geslagsdimorfisme in P. subrufa vir die eerste keer te beskryf.

Thesis (M.S. )--University of Tennessee Health Science Center, 2007
Title from title page screen (viewed on June 10, 2008). Research advisor: Edward F. Harris, PhD Document formatted into pages (xii,163 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 109-125).

The macroevolutionary pattern of Rensch’s Rule, i.e., positive allometry of sexual size dimorphism, has had mixed support in turtles. Using the largest carapace length dataset and the only large-scale body mass dataset heretofore assembled for this group, we determine (a) whether turtles conform to Rensch’s Rule at the order, suborder, and family levels, and (b) whether inferences regarding allometry of sexual size dimorphism differ based on choice of body size metric used for analyses. We compiled large databases of mean body mass and carapace length for males and females of as many populations and species as possible using mostly primary literature. We then determined scaling relationships between males and females for average body mass and straight carapace length across species of turtles using traditional and phylogenetic comparative methods. We also used linear regression analyses to evaluate sex-specific differences in the variance explained by carapace length on body mass.

In non-phylogenetic analyses, body mass supports Rensch’s Rule, whereas straight carapace length supports isometry. Using phylogenetic independent contrasts, both body mass and straight carapace length support Rensch’s Rule with strong congruence between body size metrics. More variance is explained by mass than carapace length. At the family level, support for Rensch’s Rule is more frequent when mass is used as a body size metric and in phylogenetic comparative analyses. Turtles do not differ in their mass-to-length regressions by sex. Turtles display Rensch’s Rule overall and within some families of Cryptodires, but not in Pleurodire families. At broad scales, mass and length are strongly congruent with respect to Rensch’s Rule in turtles, and discrepancies are observed mostly at the family level (which is the level where Rensch’s Rule is most often evaluated). At macroevolutionary scales, the purported advantages of length measurements over weight measurements are not supported in these ectothermic vertebrates.

I examine some of the ecological and evolutionary implications of body size in hermit crabs, with special emphasis on the upper intertidal species Clibanarius digueti. In Chapter 1 I show that body size had a far greater effect than species identity on desiccation tolerance for shell-less individuals of C. digueti, Paguristes anahuacus, Pagurus lepidus, and Phimochirus roseus. In contrast with other intertidal taxa, there was no correlation between the upper tidal limit of a species and the expected desiccation tolerance of an average-sized, shell-less individual of that species. This suggests that the gastropod shell that normally houses the hermit crab is sufficient to eliminate desiccation as a community-structuring force in this guild. Clibanarius digueti exhibits strong sexual dimorphism in body size, with almost no overlap in size between adult males and females. In Chapter 2 I show that sexual differences in the intensity of selection on size favor this dimorphism. Specifically, male mating success depended more strongly on body size than did female fecundity. In fact, the rate of increase in fecundity with body size equalled the lowest previously recorded for decapod crustaceans, suggesting that sexual size dimorphism in this species may depend more on weak fecundity selection on females than on strong sexual selection on males. Documenting contemporary selection on a character, however, is not the same as documenting that selection caused the character to evolve. Chapter 3 presents the first empirical test in a single species (C. digueti) of the hypothesis that sexual size dimorphism represents an evolutionary response to sexual differences in selection on size. The test is based on a general model that predicts crab body size as a function of shell limitations, shell fit and body size. Both males and females occupied optimally sized shells of non-preferred species, but the greater the desirability of a shell species, the greater the tendency for males to occupy tighter-fitting shells than females. Males also apparently suffere higher mortality than similarly-sized females. According to the general model, these results agree with the hypothesis that differential selection is causally involved in the evolution of sexual size dimorphism, and contradict the alternative hypothesis that energetic constraints on females produce the dimorphism.

In many terrestrial mammals, males are generally larger than females. Since shrews are the smallest living terrestrial mammals, specimens of the shrew Sorex cinereus cinereus from north central Minnesota were studied to determine if size differences between sexes also occurred at this extreme. Comparisons were based on measurements of external body lengths and individual lengths of upper quadrant locomotive muscles. External differences showed neither males nor females were consistently larger. The results from analysis of variance on individual muscle lengths showed very few significant differences between individual muscles. Those muscles that did show a significant difference were not grouped In a way that would suggest a significance due to a function specific to either sex. This study suggests that in these shrews, unlike many other living terrestial mammals, males are not larger than females.

To date, models of sexual size dimorphism do not explain selection for small females, and they are also limited in their ability to explain intraspecific variation in sexual size dimorphism. I propose that small females, in species which produce multiple clutches in a breeding season, could have a selective advantage if the interval between clutches is shorter for small clutches of eggs. When the breeding season is long, small females may produce more eggs in total than large females by producing more clutches, and thus small size could be selected for. Two populations of threespine stickleback (Gasterosteus aculeatus) showing divergence in the sexual bias of size dimorphism were used to determine if large or small females had a seasonal fecundity advantage in these multiple spawning fish, and whether the two populations had diverged in life-history characteristics (age at first reproduction, number of clutches, length of breeding season). In addition, the mechanisms by which the differences in size were achieved was investigated. Size-frequency diagrams obtained from field samples indicated that the Lewis Slough population was an annual one, while fish at the Angus Campbell site apparently survived for more than one breeding season. The larger size of females at the Angus Campbell site resulted primarily from continued growth with age, while males stopped growing in about one years time. In an environment chamber female fish from Lewis Slough grew more slowly, as they approached maturity, than males and were therefore were smaller than males. Data from field collections, fry raised to maturity in an environment chamber, and females individually monitored in captivity over the course of a breeding season indicated that the populations have diverged in life-history characters. Females from the Angus Campbell ditch site produced fewer clutches and eggs over the breeding season (a measure of reproductive effort), delayed maturity and matured at a greater size, and had a longer life-span than Lewis Slough females. These observations are more in accordance with the predictions from bet-hedging theory than r & K selection theory. Data from individually monitored females held in a common environment indicated that clutch size and interclutch interval increased with increasing body size but small females still did not attain the seasonal fecundity advantage predicted by the model. However, these results suggest that small females are capable of achieving a greater seasonal fecundity relative to large females than would be predicted by the difference in average clutch size alone. Actual counts of the total numbers of eggs produced by individuals in a breeding season showed seasonal fecundity to be independent of body size. Female body size and fecundity are more weakly linked than previously realized and this confers an increased flexibilty for responding to diverse selective pressures.
Science, Faculty of
Zoology, Department of
Graduate

O dimorfismo sexual nas espécies pode surgir a partir da seleção decorrente dos diferentes sistemas reprodutivos. Estudos comportamentais de espécies neotropicais são raros e pouco se sabe sobe as espécies brasileiras. Neste estudo, foram descritos o comportamento de três espécies neotropicais que ocorrem no Cerrado brasileiro: Acanthagrion truncatum, Argia reclusa (Coenagrionidae) e Heaterina rosea (Calopterygidae). Também foi evidenciado o dimorfismo sexual nestas espécies e investigou-se a partir de observações comportamentais, como o dimorfismo se desenvolve em espécies com diferentes táticas reprodutivas. Com os resultados obtidos, vemos que em espécies territoriais os machos são maiores do que as fêmeas, enquanto em espécies não-territoriais as fêmeas são maiores do que os machos. Sugere-se que, diferentemente de outros estudos, em Zygoptera o tipo de sistema reprodutivo pode determinar o dimorfismo sexual.
Sexual size dimorphism (SSD) can in some species result from the selection acting through different mating systems. Behavioral studies of neotropical species are rare, and few is known about the brazilian species. In this study, we described the behavior of three neotropical species that occur in the brazilian neotropical savannah: Acanthagrion truncatum, Argia reclusa (Coenagrionidae) and Heaterina rosea (Calopterygidae). We show the SSD in these species and investigates through behavioral observations, how SSD develops in species with different mating tactics. With our results, we can see that in territorial species the males are larger than females, while in non-territorial species the females are larger than males. We suggest that, unlike other studies, in Zygoptera the kind of mating system adopted by males may determinate the SSD in a species.

Le but de cette étude était d'utiliser les techniques moléculaires dans deux populations de chevreuil, pour estimer la variance du succès reproducteur des mâles et identifier les principaux déterminants de cette variance. Comme attendu du fait de son faible dimorphisme sexuel, la variance dans le succès reproducteur à vie des mâles, et donc l'opportunité pour la sélection sexuelle, sont faibles chez le chevreuil, suggérant un faible degré de polygynie. Les mâles peuvent se reproduire dès 2 ans, mais avec un succès reproducteur inférieur à celui des mâles plus âgés. Le succès reproducteur tend aussi à décroître après 8 ans. La masse corporelle, la taille des bois, et la taille du territoire des mâles, affectent positivement leur succès reproducteur, mais pas la qualité de l'habitat dans leur territoire. Cette étude apporte de nouveaux éléments sur l'évolution de la territorialité et la sélection sexuelle chez les ongulés sauvages
The aim of this study was to use for the first time molecular techniques in two populations of roe deer to estimate the variance in male breeding success and identify the main determinants of this variance. As expected from the low level of sexual size dimorphism, the variance in male lifetime breeding success, and so the opportunity for sexual selection, are low, suggesting a low polygyny level in roe deer. Males can successfully breed as young as 2 years of age, but breeding success of sub-adults is lower than that of older males. Breeding success also tends to decline after 8 years of age. Male body mass, antler size and territory size positively affect male breeding success, but not the habitat quality within the territory. This study provides new insights into the evolution of mating systems and sexual selection in wild ungulates

Many species use color during courtship displays, with the more colorful individuals often selected as potential mates. Female blue crabs, Callinectes sapidus, display prominent red markings on their chelipeds, which is absent in males. I tested the hypothesis that females use this sexual dimorphism as an effective signal to potential mates. Body size was positively correlated with size of the colorful pattern on the crusher dactyl. Digital imaging techniques were used to examine and quantify a pattern of coloration in the female blue crab. Morphometric measurements were made using digital images of the carapace and chelae of crabs collected along the Gulf of Mexico coast in Galveston, Texas. Color complexity was examined on digital images of the chelae using Adobe? Photoshop? and Image J. Specific wavelengths were selected and their presence within the attribute quantified and evaluated. To determine whether male blue crabs prefer more colorful females, males were given a choice between females of different female coloration. Males displayed more often and directed more courtship displays towards the more colorful females. I hypothesize that male blue crabs use cheliped coloration as a visual cue for mate selection.

Yellow perch (Perca flavescens) exhibit an estrogen stimulated sexual sizedimorphism (SSD) wherein females grow faster and larger than males. In an effort togain better understanding of this phenomenon, several genes associated with sexualdevelopment, reproduction and growth were cloned, including prolactin (PRL),somatolactin (SL), insulin-like growth factor-I (IGF-Ib), the estrogen receptors (ER?? andER??a) and ovarian aromatase (CYP19A1). Real-time quantitative PCR (qPCR) assaysfor all the genes listed above, plus growth hormone (GH), were developed to measuremRNA levels in pituitary, liver and ovary.Adult fish were collected from Lake Erie in the spring (May) and autumn(October) over two years and tissue mRNA levels, body weight, age, gonadasomaticindex (GSI) and hepatasomatic index (HSI) were determined. Sex-specific differencesincluded females having higher body weights, HSI and liver ER?? mRNA levels thanmales and males having higher liver ER??a and liver CYP19A1 mRNA levels thanfemales. Season had a significant effect on growth factors (GH and IGF-Ib), with highermRNA levels in spring, which corresponded with higher liver CYP19A1 mRNA levels.Ovary CYP19A1 mRNA levels, which were higher in autumn, had a significant negativecorrelation with GH and IGF-Ib mRNA levels and liver ER??a mRNA levels had asignificant positive correlation with IGF-Ib mRNA levels.A brood of juvenile yellow perch was sampled through the first year ofdevelopment up to 421 days post-hatching (dph). There was a significant effect of dphon body weight, GH, PRL, SL, IGF-Ib, liver ER??, liver ER??a and ovary CYP19A1mRNA levels. Only liver ER??a mRNA had a significant effect of sex and exhibitedsignificant differences between males and females at 379 and 421 days post-hatching(dph). This work on yellow perch can provide predictive capabilities for estrogendependentphysiological processes in other species, especially teleosts, and can also makeyellow perch an exciting option for future ecotoxicogenomic studies.

A biologia reprodutiva dos Amphisbaenia é uma das menos estudadas entre os répteis, havendo na literatura informações sobre o ciclo reprodutivo, dimorfismo sexual e fecundidade de poucas espécies do grupo, além de informações pontuais acerca de oviposturas. A histologia das vias genitais, da mesma forma, foi pouco estudada, tornando difícil uma melhor caracterização dos ciclos de machos e fêmeas. No Brasil são encontradas cerca de um terço das espécie do grupo, distribuídas por regiões com diferentes características macroclimáticas. Este trabalho teve por objetivo caracterizar o ciclo reprodutivo de machos e fêmeas de onze espécies brasileiras da família Amphisbaenidae, com base em dados de dissecção e histologia, e analisá-los comparativamente tendo como referência a filogenia molecular já proposta para as Amphisbaenidae do Brasil. Objetivou-se ainda realizar uma análise preliminar da relação entre os ciclos reprodutivos observados e variações sazonais de temperatura e precipitação. Para tanto, foram analisados espécimes depositados em coleções zoológicas, que tiveram suas gônadas e órgãos urogenitais examinados e medidos. Foram ainda realizadas análises histológicas de ovidutos, testículos, ductos deferentes e rins de espécimes coletados em diferentes meses do ano, para análise de sua morfologia e caracterização dos ciclos espermatogênico, de estocagem de esperma e de atividade do segmento sexual renal. Foram ainda analisados espécimes e lâminas histológicas de duas espécies da família Blanidae e uma da família Trogonophidae, permitindo uma melhor discussão das características observadas tendo como referência a filogenia do grupo. Foram analisados também dados de dimorfismo sexual de tamanho do corpo e de fecundidade. Os machos de quatro espécies de Amphisbaenidae amostradas apresentaram ciclos reprodutivos assazonais, com períodos de repouso não sincrônicos entre os indivíduos. Os machos de outras sete espécies de Amphisbaenia, duas de Blanidae e uma de Trogonophidae apresentaram ciclos sazonais. Todas as sete espécies para as quais o ciclo das fêmeas pôde ser caracterizado são sazonais nesse aspecto. Os ciclos de machos foram comparados quanto à época e duração das fases de espermatogênese, estocagem de esperma e atividade secretora do segmento sexual renal, tendo sido obtidas evidências de relação entre essas características e a filogenia do grupo. As fases reprodutivas das espécies de Amphisbaenia brasileiras são mais extensas em comparação com aquelas observadas em Blanidae e Trogonophidae. Também se obtiveram evidências preliminares da relação entre sazonalidade dos ciclos reprodutivos e variações anuais de temperatura e precipitação. Em sete espécies de Amphisbaenidae, foi observado dimorfismo sexual quanto ao comprimento rostro-cloacal ou ao comprimento da cauda. A fecundidade das fêmeas varia entre um e quatro ovos, na maioria das espécies analisadas, mas pode chegar a sete em Amphisbaena mertensi e nove em Amphisbaena trachura.
The reproductive biology of the Amphisbaenia is one of the less known among reptiles. In the literature, there are information on the reproductive cycle, sexual dimorphism, and clutch size for few species, and scarce data on clutches of eggs. Similarly, the histology of the genital tract was studied in few species, which makes difficult to characterize properly the reproductive cycles of males and females. Almost one third of the species of the group occur in Brazil, in regions with different climates. This study aimed to characterize the reproductive cycle of males and females of eleven Brazilian species of the family Amphisbaenidae, based on the dissection and histological analysis of gonads and genital ducts, and to compare the obtained data with regard to the molecular phylogeny already proposed for the Brazilian species of this family. It also aimed to analyze preliminarily the relation between the observed reproductive cycles and seasonal variations of temperature and precipitation. Specimens from zoological collections were analyzed to examination and measuring of the gonads and urogenital organs. Samples of the oviducts, testis, ductus deferens and kidneys from specimens collected in various months were also analyzed using light microscopy to characterize the cycles of spermatogenesis, sperm storage, and activity of the sexual segment of the kidney. Specimens and histology slides of two Blanidae species and one Trogonophidae species were also analyzed, allowing a better discussion of the characteristics of the reproductive cycles referring to the phylogeny of the group. Sexual size dimorphism and clutch size were also analyzed. The males of four Amphisbaenidae species presented aseasonal reproductive cycles, with testicular recrudescence and rest phases not synchronized among individuals. The males of the other seven Amphisbaenidae species, two Blanidae species and one Trogonophidae species presented seasonal reproductive cycles. The seven species for which the reproductive cycles of females could be characterized are seasonal in this regard. The male reproductive cycles were compared considering seasonality and the length of spermatogenesis, sperm storage and secretory activity of the sex segment of the kidney. Evidence of relation between the reproductive cycle characteristics and the phylogeny of the family Amphisbaenidae was obtained. The reproductive seasons of Brazilian Amphisbaenia are longer than those observed in Blanidae e Trogonophidae. Preliminary evidence on the relation between reproductive cycle seasonality and annual variations of temperature were also obtained. Seven Amphisbaenidae species presented sexual dimorphism in snout-vent length or caudal length. Clutch size varies from one to four eggs in most species, but reaches seven eggs in Amphisbaena mertensi and nine in Amphisbaena trachura.

O dimorfismo sexual varia consideravelmente entre populações dentro de uma mesma espécie. Essa variação na direção e na magnitude do dimorfismo sexual é, em parte, devida às diferenças sexuais na respostas plásticas às condições e aos recursos ambientais. Por meio de experimentos em laboratório, sabe-se que a temperatura e a disponibilidade de alimento são fatores importantes na geração de variações morfológicas inter-individuais e que seus efeitos diferem entre machos e fêmeas. Usamos indivíduos da tesourinha Labidura xanthopus (Dermaptera) coletados em 20 localidades ao longo da costa brasileira para investigar como o tamanho corporal e o tamanho do armamento de machos e fêmeas variam em um gradiente natural de temperatura. O tamanho do corpo diminuiu com o aumento da temperatura, mas o dimorfismo sexual se manteve constante ao longo do gradiente de temperatura. Para o tamanho do armamento, encontramos uma relação negativa para machos e positiva para fêmeas. Conseqüentemente, a magnitude do dimorfismo sexual no tamanho do armamento diminuiu ao longo do gradiente de temperatura. Para entender o efeito da disponibilidade de alimento sobre a expressão de características morfológicas em cada um dos sexos, manipulamos a dieta durante o desenvolvimento de indivíduos provenientes de uma população de clima tropical e uma de clima temperado. Independente da população, o dimorfismo sexual foi causado por diferenças sexuais na dependência de condição. Machos e fêmeas diferiram não apenas na magnitude da resposta, mas também na direção. Em relação ao comprimento relativo dos fórceps, em particular, os resultados obtidos em laboratório não apóiam que a variação encontrada em campo se deve à disponibilidade de alimento. Outros fatores que não levamos em consideração, tais como densidade populacional, podem exercer um papel importante na resposta de machos e fêmeas em relação ao tamanho do armamento. Por fim, mais estudos experimentais comparando populações com diferenças marcantes de condições ambientais poderão lançar luz sobre quais fatores ecológicos podem ter favorecido a evolução do dimorfismo sexual dependente de condição
Sexual dimorphism varies considerably among populations within species. This variation in the direction and magnitude of sexual dimorphism is partially explained by sexual differences in phenotypically plastic responses to environmental conditions and resource availability. Laboratory experiments have already shown that temperature and food availability are important factors promoting inter-individual morphological variation and that their effects differ between males and females. We used individuals of the earwig Labidura xanthopus (Dermaptera) collected from 20 Brazilian localities to investigate how body size and weapon size of males and females vary across a natural temperature gradient. Body size decreased with increasing temperature, but sexual size dimorphism remained constant across the temperature gradient. For weapon size, we found a negative relationship for males and a positive relationship for females. Thus, the magnitude of sexual dimorphism in weapon size decreased across the temperature gradient. To understand the effect of food availability on the expression of morphological traits in each sex, we manipulated the diet of individuals from a tropical and temperate population. Regardless of the population, sexual dimorphism was caused by sex-differences in condition dependence. Males and females differed not only in the magnitude of their responses, but also in the direction. Regarding the relative length of the forceps, in particular, our results do not support the interpretation that the morphological variation observed in the field is explained by differences in food availability. Other factors not considered here, such as population density, may play an important role in determining weapon size variation in males and females under natural conditions. Finally, more experimental studies comparing populations with marked differences in environmental conditions may shed light on which ecological factors have favored the evolution of condition-dependent sexual dimorphism

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
he reproduction in insects is affected by a wide array of factors that acts directly on the reproductive output, related with offspring quality and quantity: the interaction, by physical, chemical and visual cues, between insects and host plants; the larval growth rate affecting adult size and mating rate, as a mechanism of reproductive sucess. Thus, studies on insect reproduction are recommended to help estimate and to understand population dynamics, for both endangered species and to control crop pests. The tomato fruit borer Neoleucinodes elegantalis Guenée (Lepidoptera: Crambidae) is one of the most important pest species on Solanaceae in Brazil, and the aims of this works is to study this species regarding to: (i) the role of physical, chemical and visual cues on oviposition; (ii) the causes of sexual dimorphism and (iii) how male mating history affects his ability to obtain new matings. This work also propose an equation that can help to estimate the initial size of fragmented spermatophores found inside the reproductive tracts of females, based on measures of the fragments. The results showed: (i) that physical and chemical cues increase significantly the oviposition of N. elegantalis, as well showed that light intensityalso affect oviposition; (ii) that differences in dayly growth rate is the cause of the observedsexual dimorphism in this species, and (iii) that recently mated males are equally able to achieve new matings as virgin ones, within at least 24-h period.
A reprodução em insetos depende de diversos fatores que afetam diretamente o sucesso reprodutivo, em relação à qualidade e quantidade da progênie: a interação mediada por sinais químicos, físicos e visuais, entre o inseto e seu hospedeiro; taxa de crescimento larval relacionado com o tamanho final do adulto e a frequência de cópulas, como mecanismo de sucesso reprodutivo. Portanto, o estudo da reprodução de insetos é recomendado para se estimar e compreender a dinâmica de populações, tanto para a preservação de espécies em extinção, como para o controle de pragas agrícolas. A broca-pequena-do-tomateiro Neoleucinodes elegantalis Guenée (Lepidoptera: Crambidae) é uma das pragas mais importantes das solanáceas no Brasil, o que estimula o desenvolvimento de qualquer estudo voltado para a melhor compreensão de sua biologia e dinâmica populacional. Assim o objetivo deste trabalho é estudar (i) o efeito dos sinais físicos, químicos e visuais que afetam sua oviposição; (ii) as causas do seu dimorfismo sexual e (iii) o efeito da experiência de cópula de machos na sua capacidade de obter novosacasalamentos. Este trabalho ainda propõe uma equação que possa auxiliar em estimar o tamanho inicial de um espermatóforo já fragmentado, baseado nas medidas do fragmento encontrado no trato reprodutivo das fêmeas. Os resultados demonstram que: (i) os sinais físicos e químicos oferecidas estimulam significativamente a oviposição de N. elegantalis, bem como revela quepistas visuais afetam a oviposição; (ii) que a diferença na taxa diária de crescimento larval é responsável pelo dimorfismo sexual nesta espécie e (iii) que machos recém-copulados têm a mesma chance de conseguir uma nova cópula que um macho virgem, num período de 24 horas.

Males and females differ in morphology and behaviour, so that selection acts differently on the two sexes. This changes the relative reproductive success of males and females, and it is beneficial for parents to bias the sex ratio of their broods in favour of the sex with the best survival and breeding prospects. Differences between the sexes and brood sex ratio in Tengmalm’s owl (Aegolius funereus) in northern Sweden were investigated, using a molecular sexing technique based on PCRamplification of sex-linked CHD1 genes. Among owls caught during autumn migration, females were commoner than males, especially within juveniles. However, in contrast to earlier studies, it was shown that adult males sometimes undertake migratory movements indicatory of nomadism. Measurements of these owls revealed that sexual size dimorphism in Tengmalm’s owl is not as great as previously reported from studies carried out during the breeding season. Females were slightly larger (4% by mass) than males, probably owing to the different roles of males and females during breeding, when this dimorphism is greater. The size difference between male and female nestlings was found to be similar to that for adults in autumn, and to investigate whether this led to differential mortality, the effect of supplementary feeding on mortality of male and female nestlings was studied. Supplementary feeding reduced male mortality when vole abundance was low, and it was concluded that larger female nestlings out-competed their smaller brothers, who then suffered increased mortality when food was scarce. Recruitment of male nestlings into the breeding population declined with decreasing food supply at the time of fledging, a pattern not observed in females. Juvenile males were therefore more vulnerable to food shortage than females, both in the nest and after fledging. Mean brood sex ratio varied significantly among years characterized by different phases of the vole cycle and associated vole abundance. Broods were male-biased (63% males) in a year when the food supply was favourable during spring and summer, neutral (50%) in a year with an intermediate food supply, and female-biased (35% males) in a year when food was in short supply. Parents appeared to adaptively adjust the sex ratio of their broods according to the relative mortality risk and reproductive potential of sons and daughters.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Right after the arising of the Panama isthmus, the family Canidae colonized South America, around 2.6-2.4 million years ago. Although canids radiation in South America is recent, this region holds the largest canid diversity in the world, with more than 10 extant species. This great diversity is also notable when dealing with the ecomorphological variation of these animals. The maned-wolf (Chrysocyon brachyurus), a large omnivore, and the bush-dog (Speothos venaticus), a small hypercarnivore, are the extreme exemples of this variation. Such shape diversity can be potentially explained by both abiotic, such as climate, and biotic factors, like competition. These factors may have contributed for stabilizing the south-american canids community. Thus, this study aimed to investigate what drives this ecomorphological amplitude, as well as to understand how can similar species coexist when overlapping their distributional ranges, such as the crab-eating fox (Cerdocyon thous), which has sympatric areas with Lycalopex vetulus and L. gymnocercus, two foxes ecologically similar to Cerdocyon thous. To answer these questions, 431 especies were photographed in nine South-American museums. Through geometric morphometric procedures, it was possible to quantify the phenotypic variation of eight canid species (Atelocynus microtis, C. thous, C. brachyurus, L. culpaeus, L. griseus, L. gymnocercus, L. vetulus e S. venaticus) throughout their geographical range and then test the contribution of biotic and abiotic factors driving this variation. The evidences presented in this study suggest C. thous alters its shape and body size when in sympatry with two Lycalopex species, pattern described by character displacement , which is when similar species shift their phenotype in order to minimize competition. Besides, C. thous also follows the Bergmann s rule, which predicts that body size increases at larger latitudes. When considering the canid community as a whole, climate was identified as the main factor contributing to phenotypic variation in these animals. Competition has a weaker impact in south-american canids skull morphology, although it may have played a larger role in the past, when the ecomorphological diversity in the subcontinent was even larger.
Logo após a emergência completa do istmo do Panamá, a família Canidae colonizou a América do Sul, há, aproximadamente, 2.6-2.4 milhões de anos atrás. Embora a radiação dos canídeos seja recente na América do Sul, esta região compõe a maior diversidade atual de espécies desta família no mundo, com mais de 10 espécies viventes. Esta grande biodiversidade também é notável na variação ecomorfológica destes animais. Exemplo disso são os dois extremos desta variação: o lobo-guará (Chrysocyon thous), um animal onívoro de grande tamanho corporal; e o cachorro-vinagre (Speothos venaticus), espécie hipercarnívora de pequeno porte. Tamanha diversidade de formas pode potencialmente ser explicada tanto por fatores abióticos, como o clima, e bióticos, como a competição. Ambos os fatores podem ter contribuído para a estabilização da comunidade de canídeos sul-americana. Por isso, este estudo se propôs a investigar o que impulsionou esta amplitude ecomorfológica, bem como entender como espécies mais similares coexistem quando em sobreposição distribucional, como o graxaim-do-mato (Cerdocyon thous), que possui área simpátrica a Lycalopex vetulus e L. gymnocercus, duas raposas ecologicamente similares a Cerdocyon thous. Para tanto, 431 espécimens foram fotografados em nove museus da América do Sul. Através de procedimentos de morfometria geométrica, foi possível quantificar a variação fenotípica de oito espécies de canídeos (Atelocynus microtis, C. thous, C. brachyurus, L. culpaeus, L. griseus, L. gymnocercus, L. vetulus e S. venaticus), ao longo de sua distribuição geográfica, e então testar a contribuição dos fatores bióticos e abióticos nesta variação. As evidências deste estudo sugerem que C. thous altera sua forma e tamanho corporal quando em simpatria com as duas espécies de Lycalopex, padrão descrito pelo deslocamento de caráter , quando espécies semelhantes alteram seu fenótipo em simpatria, a fim de minimizar a competição. Além disso, C. thous também segue a regra de Bergmann, que prevê um aumento de tamanho corporal com o aumento da latitude. Ao considerar a comunidade de canídeos como um todo, o clima foi identificado como o fator que mais contribuiu para a variação fenotípica destes animais. A competição, por sua vez, tem um impacto mais fraco na morfologia do crânio dos canídeos sul-americanos, embora possa ter tido uma maior contribuição no passado, quando a diversidade ecomorfológica no subcontinente era ainda maior.

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The Neotropical damselfly Telebasis carmesina (Odonata: Coenagrionidae) is a common species in the Cerrado, a Brazilian savanna and even though, nothing is known about its natural history and ecology. This study aimed to investigate the population ecology, the habitat use and the breeding behavior of this species. It was conducted at a pond in the Natural Particular Reserve at Clube de Caça e Pesca Itororó de Uberlândia, between July/2008 and October /2009. The data was collected through the markrecapture method, using an insect net and a metal precision caliper. In addition, 81 hours of behavioral observations was taken. An amount of 1133 individuals were captured. December and November/2008 comprised the highest number of marked males, while September and October/2008 presented the higher abundance of females. The abundance of individuals was directly related to the air temperature and relative air humidity and it affects the individuals size, that is, the bigger the males abundance, the smaller was the total length of them, which generally are smaller than females. The males size also varied between the seasons of the year, except in summer and auntumn, and the females had different average of sizes between spring and summer months. The males longevity varied between the seasons and during the breeding season October to April was 7,099 (±0,719; X±SE) days. In this study, both males and females had concentrated mainly in the pond and used the macrophytes Eliocharis sp. and Pontederia parviflora as main perching surface, mating and oviposition. The polygynous mating system through scramble competition was evidenced during observations and supported by the smaller size of males and the absence of territory guarding behavior. The breeding behavior was frequently observed during the midmorning. T. carmesina s mate involved sperm transfer to edeagous, tandem and wheel positions and some evidences suggest that there is males sperm displacement in the species. The oviposition occurs together with the male, in tandem. Sex ratio varied throughout the months, with the closest value in relation to 1:1 ratio in September (1:3,48) and the most distinct value in January (1:27,4). Males exhibited three types of aggressive displays, similarly to other studies in literature: i) chase, when a male run after other male, going back to its original position or its position is displaced by the other male; ii) threat display or wing spread, when a male, realizing the approach of another male, spreads his wings, and iii) attack, which can occurs through the use of the legs, abdominal appendages or mouth parts. The agonistic behavior is directed toward to conspecific males; however aggressive interactions can also occur between heterospecific individuals. Telebasis carmesina presents important features related to sexual selection, such as sexual size dimorphism and sex ratio male biased. Moreover, the habitat use by males and females are spatially and temporarily different.
Embora seja comum no cerrado, nada se sabe sobre a história natural e ecologia da libélula neotropical Telebasis carmesina (Odonata: Coenagrionidae). Nesse sentido, os objetivos desse estudo foram investigar a ecologia populacional, uso do habitat e o comportamento reprodutivo dessa espécie. O estudo foi conduzido em uma lagoa situada na RPPN do Clube de Caça e Pesca Itororó de Uberlândia MG, entre os meses de julho de 2008 e outubro de 2009. Os dados foram obtidos utilizando-se o método de captura-marcação-recaptura, com o auxílio de uma rede entomológica e um paquímetro metálico de precisão e de observações comportamentais, totalizando 81 horas de observação. No total, 1133 indivíduos foram capturados. Os meses com maior número de machos capturados foram dezembro e novembro de 2008. Setembro e outubro de 2008 foram os meses em que houve maior abundância de fêmeas. A abundância dos indivíduos está diretamente relacionada com a temperatura e umidade relativa do ar e afeta o tamanho dos indivíduos. Quanto maior a abundância de machos, menor o comprimento total deles, que obtiveram tamanho menor que as fêmeas. O tamanho dos machos também variou entre as estações, exceto entre verão e outono e as fêmeas apresentaram médias de tamanho diferentes nos meses da primavera e verão. A longevidade dos machos variou entre as estações e durante a estação reprodutiva outubro a abril e foi de 7,099 (±0,719; X±EP) dias. Tanto machos quanto fêmeas concentraram-se principalmente na lagoa e utilizaram as macrófitas Eliocharis sp. e Pontederia parviflora como principais superfícies de pouso, cópula e oviposição. O sistema de acasalamento poligínico de competição por interferência foi evidenciado durante as observações e corroborado pelo tamanho dos machos e ausência de guarda de territórios O comportamento reprodutivo foi mais freqüente durante o meio da manhã. A cópula de T. carmesina envolveu a transferência de esperma para o edeago, o tandem , a wheel position . A oviposição ocorre sempre com o acompanhamento do macho, em tandem . A razão sexual atingiu maior equivalência em relação à razão 1:1 no mês de setembro (1:3,48) e maior diferença no mês de janeiro (1:27,4).Os machos exibiram três tipos de comportamentos agressivos: i) perseguição, quando um macho persegue o outro, voltando logo a sua posição original, ou sua posição é tomada pelo outro; ii) intimidação ou wing spread , um macho, quando percebe a aproximação de outro, abre suas asas e iii) ataque, que pode ocorrer através do uso das pernas, apêndices abdominais ou peças bucais. Machos apresentam comportamento agonístico direcionado a outros machos da mesma espécie e também são agressivos com indivíduos de outras espécies. A espécie estudada apresenta dimorfismo sexual de tamanho e razão sexual altamente direcionada para machos. Machos e fêmeas utilizam diferencialmente o habitat, tanto espacial quanto temporalmente.
Mestre em Ecologia e Conservação de Recursos Naturais

Apesar dos morcegos hematófagos serem muito estudados, diversos aspectos de sua biologia e de seu papel na transmissão da raiva ainda não são conhecidos. O objetivo da presente tese foi estudar os abrigos diurnos, os agrupamentos e o comportamento agonístico do morcego hematófago comum, Desmodus rotundus, e sua relação com a raiva dos herbívoros no Vale do Paraíba. Foi possível também obter informações sobre as duas outras espécies de morcegos hematófagos, especialmente de Diphylla ecaudata. Entre 2011 e 2014, dados sobre abrigos diurnos, composição dos agrupamentos, lesões corporais, diagnóstico de raiva e sorologia antirrábica de D. rotundus foram obtidos nos municípios de Jacareí, Paraibuna, Pindamonhangaba, Salesópolis, Santa Branca e São Luiz do Paraitinga no Vale do Paraíba, Sudeste do estado de São Paulo, Sudeste do Brasil. Foram estudados 14 abrigos diurnos de D. rotundus, dos quais 12 eram construções abandonadas na área rural. Desmodus rotundus partilhou abrigos diurnos com apenas cinco espécies de filostomídeos: Diphylla ecaudata, Chrotopterus auritus, Carollia perspicillata, Glossophaga soricina e Anoura caudifer. O tempo de recolonização desses abrigos diurnos por D. rotundus foi em média 12,5 meses, com uma variação entre três e 25 meses. O tamanho dos agrupamentos variou de dois a 79 indivíduos, com uma média de 15,6 morcegos/grupo. Fêmeas foram encontradas em 15 agrupamentos, com uma média de 13 fêmeas e uma variação entre uma e 55 fêmeas/grupo. Por outro lado, machos estiveram mais presentes nos agrupamentos, ocorrendo em quase todos (N=21), com uma média de 7,1 machos/grupo e uma variação de um a 24 machos. Sete agrupamentos foram considerados de machos solteiros. Onze dos 22 agrupamentos eram constituídos de colônia e grupo de machos solteiros. O dimorfismo sexual no comprimento do antebraço de D. rotundus do Vale do Paraíba foi estatisticamente significativo e sugere que as fêmeas são maiores 13 do que os machos. Lesões corporais, atribuídas às mordeduras provocadas por outros morcegos, foram encontradas em 76,7 por cento dos indivíduos de D. rotundus, tanto em machos como em fêmeas. A região mais atingida foram as membranas alares, com 68 por cento , porém lesões nas orelhas, face e membros foram menos frequentes (23,1 por cento nas fêmeas e 26,9 por cento nos machos). Acredita-se que as lesões nessas regiões sejam mais importantes nos mecanismos de transmissão de raiva. Apesar de ter analisado 310 amostras de encéfalos de D. rotundus do Vale do Paraíba, o resultado foi negativo em todas as amostras. A sorologia mostrou que todos os morcegos apresentaram positividade em diferentes graus. Contudo, se considerarmos o ponto de corte 0,5 UI/ml, o número de indivíduos positivos caiu para 30,1 por cento (N=90), sendo 30,9 por cento nas fêmeas e 28,8 por cento em machos. Apesar de nenhum indivíduo de D. rotundus positivo para a raiva ter sido encontrado no Vale do Paraíba durante a presente tese, a sorologia positiva de, pelo menos, 30 por cento mostra que há vírus da raiva circulando em sua população. Essa alta circulação viral pode ter sido favorecida pelas interações agonísticas, que causam lesões em mais de 75 por cento dos morcegos, a formação compacta (em penca) dos agrupamentos, o grooming social, a reciprocidade e partilha alimentar
Despite the hematophagous bats are very studied, many aspects of their biology and their role in the transmission of rabies are not yet known. The aim of this thesis was to study the diurnal shelters, groups and the agonistic behavior of the common hematophagous, Desmodus rotundus, and its relation to the cattle rabies in the Paraíba Valley. It was also possible to obtain information about the two other species of vampire bats, especially Diphylla ecaudata. Between 2011 and 2014, data on diurnal shelters, composition of groups, body injuries, diagnosis of rabies and rabies serology D. rotundus were gathered from the cities of Jacarei, Paraibuna, Pindamonhangaba, Salesópolis, Santa Branca and São Luiz do Paraitinga in the Valley Paraíba, Southeastern of São Paulo State, Southeastern Brazil. Fourteen diurnal shelters of D. rotundus were studied here and 12 were abandoned buildings in rural areas. Desmodus rotundus shared daytime shelters with only five species of phyllostomid bats: Diphylla ecaudata, Chrotopterus auritus, Carollia perspicillata, Glossophaga soricina and Anoura caudifer. The time of recolonization of these roosts by D. rotundus was on average 12.5 months, ranging from three to 25 months. The size of the groups ranged from two to 79 individuals, with a mean of 15.6 bats/group. Females were found in 15 groups with an average of 13 females/group and ranging between one and 55 females. Moreover, males were present in most groups from Paraíba Valley, occurring in almost all (N = 21), with an average of 7.1 males/group, and a variation of 24 males. Seven groups were considered to be single males groups. Eleven of the 22 groups were made up of colony and single male groups. Sexual dimorphism in the forearm length of D. rotundus from the Paraíba Valley was statistically significant and suggests that females are larger than males. Body Injuries, attributed to bites caused by other bats were found in 76.7 per cent of individuals of D. rotundus, in both males and females. The most affected region was the wing membranes, with 68 per cent , but lesions on the ears, face and limbs were less frequent (23.1 per cent in females and 26.9 per cent in males). It is believed that injuries in these regions are more important in the rabies transmission mechanism. Despite having analyzed 310 samples of brains of D. rotundus from the Paraíba Valley, the result was negative in all samples. Serology showed that all bats were positive in varying degrees. However, if we consider the cut off 0.5 IU/ml, the number of positive samples dropped to 30.1 per cent (N = 90) and 30.9 per cent in females and 28.8 per cent males. Although no individual of D. rotundus positive for rabies was found in the Paraíba Valley during this thesis, the positive serology at least 30 per cent shows that there is rabies virus circulating in this bat population. This high viral circulation may have been favored by agonistic interactions, that cause lesions in more than 75 per cent of the bats, the compact formation (in clusters) of groups, social grooming, reciprocity and food sharing.

Aciphylla species (wild spaniard/speargrass) are an iconic component of the Australasian high country flora, but their reproductive system is enigmatic. They are insect-pollinated dioecious mast seeders (synchronous highly variable seed production), which seems maladaptive. The resource supply to pollinators is highly variable, yet dioecious plants are dependent on pollinators, and dioecious masting requires male and female plants to flower synchronously. Floral display in Aciphylla is relatively large, with tall inflorescences bearing thousands of flowers, suggesting that plants would not have the resources to produce such large stalks every year. But why do they have such huge inflorescences in the first place? I tested whether pollinator attraction is providing an economy of scale which favours intermittent production of very large inflorescences, by manipulating floral display size during a high-flowering year and measuring insect visitation rates and seed set (female reproductive success). Using space-for-time substitution and selective removal of male inflorescences, I also tested whether female seed set was affected by distance to flowering male plants (i.e. changes in local pollen availability) to see if flowering asynchrony would reduce pollination success. Bags were used to exclude pollination by insects and test for wind pollination, and hand pollination was done to test for pollen limitation. Insect surveys suggest that Aciphylla has a generalist pollination system (to avoid satiating a specialist pollinator during 'mast' years'). Male inflorescences received significantly more visits than females, and some seeds were set inside bags (although only 20-30%), suggesting wind pollination may occur at low levels. Seed set rate was higher for taller inflorescences with greater flowering length in A. aurea but tall inflorescences with excess flowers led to a decrease in seed set rates in A. scott-thomsonii. Hand pollination significantly increased seed set rates although these effects were not as large as expected (e.g. 10% increases from natural to hand-pollinated inflorescences were typical). There was no evidence for resource limitation in any species. Female plants in dense flowering populations had higher seed set rates, and individual floral display size in females was particularly important when females were 'isolated' from males. Insect visitation rates were generally higher on inflorescences with a larger floral display, suggesting that display size is important for pollinator attraction. Overall, these results suggest that the pollinator-attraction benefits of such a large floral display (at both the plant and population level) are possibly providing an economy of scale, although the relative effects are small.

In many gonochoristic fish, sex is plastic since it can be altered by the influence of environmental factors. In this thesis, using the European sea bass (Dicentrarchus labrax) model, a teleost fish with a polygenic sex determining system influenced by the environment, we have studied the effects of different environmental factors —including food supply, elevated temperatures and presence of estrogens— on growth, sex differentiation and gonadal development of juveniles. Global analysis of gene expression was carried out by a custom-made microarray. We found that, like in mammals, sex determines growth and that the first sex-related differences in growth are established before the appearance of the first molecular markers indicative of sex. Further, the juvenile testis transcriptome is influenced by poor growth during sex differentiation, while proper food supply during juvenile development is able to rescue the testis transcriptome of previously poor-growing individuals. We found that the previously observed masculinization as a result of elevated temperatures is caused by long-lasting effects at the transcriptomic level, by favoring the expression of male-related genes and decreasing that of female-related genes. In contrast, exposure to estrogen negatively affects both male- and female-related genes and pathways. Interestingly, the expression patterns of a suite of genes related to epigenetic regulatory mechanisms of gene expression showed different degrees of dependency to genetic background, developmental time and external influences according to their functional category.
A molts peixos gonocoristes, el sexe és plàstic donat que pot ésser alterat per la influència de factors ambientals. En aquesta tesi, utilitzant el llobarro (Dicentrarchus labrax) com a model, un peix teleosti amb un sistema poligènic de determinació del sexe influït per l'ambient, hem estudiat els efectes de diferents factors ambientals —incloent la disponibilitat d'aliment, temperatures elevades i presència d’estrògens— en el creixement, la diferenciació sexual i el desenvolupament gonadal dels juvenils. L'anàlisi global de l'expressió gènica s'ha realitzat mitjançant un xip d’ADN fet a mida. Hem trobat que, de la mateixa manera que ocorre en els mamífers, el sexe determina el creixement i que les primeres diferències en el creixement vinculades amb el sexe s'estableixen prèviament a l'aparició dels primers marcadors moleculars indicatius del sexe. A més, el transcriptoma de testicles juvenils està influït per un creixement pobre durant la diferenciació sexual, mentre que un subministrament adequat de menjar durant l’etapa juvenil és capaç de rescatar el transcriptoma testicular d’animals amb un pobre creixement previ. Hem trovat que la masculinització observada anteriorment com a resultat de les temperatures elevades està causada per efectes persistents a nivell transcriptòmic, afavorint l'expressió de gens relacionats amb el desenvolupament masculí i disminuint la dels gens relacionats amb el desenvolupament femení. Per contra, l'exposició a estrògens afecta negativament tant als gens relacionats amb el desenvolupament masculí com el femení. És destacable com els patrons d'expressió d'una sèrie de gens relacionats amb la regulació epigenètica de l’expressió gènica mostren graus diferents de dependència a factors genètics, període del desenvolupament i factors ambientals segons la seva categoria funcional.

[For the Abstract, please see the PDF files below, namely "front.pdf"] CONTENTS. Chapter 1 Introduction. Chapter 2 Gross and microscopic visceral anatomy of the male Cape fur seal with reference to organ size and growth. Chapter 3 Age determination and growth in the male Cape fur seal: part one, external body. Chapter 4 Age determination and growth in the male Cape fur seal: part two, skull. Chapter 5 Age determination and growth in the male Cape fur seal: part three, baculum. Chapter 6 Suture age as an indicator of physiological age in the male Cape fur seal. Chapter 7 Sexual dimorphism in the adult Cape fur seal: standard body length and skull morphology. Chapter 8 Reproduction in the male Cape fur seal: age at puberty and annual cycle of the testis. Chapter 9 Diet and foraging behaviour of the Cape fur seal. Chapter 10(a) The Impact of the fur seal industry on the distribution and abundance of Cape fur seals. Chapter 10(b) South African Airforce wildlife rescue: Cape fur seal pups washed from Black Rocks, Algoa Bay, during heavy seas, December 1976. Chapter 11(a) Operational interactions between Cape fur seals and fisheries: part one, trawl fishing. Chapter 11(b) Operational interactions between Cape fur seals and fisheries: part two, squid jigging and line fishing. Chapter 11(c) Operational interactions between Cape fur seals and fisheries: part three, entanglement in man-made debris. Chapter 12 Concentrations of heavy metals (Cd, Cu, Pb, Ni & Zn) and organochlorine contaminants (PCBs, DDT, DDE & DDD) in the blubber of Cape fur seals. Chapter 13 Endoparasites of the Cape fur seal. Chapter 14(a) Preliminary investigations of shark predation on Cape fur seals. Chapter 14(b) Aggressive behaviour of an adult male Cape fur seal towards a great white shark Carcharodon carcharias. Chapter 15 Conclusions and future directions.

This project describes various aspects of the breeding ecology and behaviour of the brown falcon Falco berigora, a common but poorly study Australian raptor. In particular it examines (a) the main influences on reproductive success; (b) tests predictions of theories proposed to explain the evolution and maintenance of sexual size dimorphism (RSD; females the larger sex) in raptors; and (c) investigates sex allocation patterns in the light of current sex ratio and parental investment theory. The study was conducted between July 1999 and June 2002 approximately 35 km southwest of Melbourne, at the Western Treatment Plant (WTP), Werribee (38°0’S 144°34’E) and surrounds, a total area of approximately 150 km2.¶ ...

In this thesis, I use an artificial selection experiment and multivariate simulation modelling to study some basic questions concerning the evolution of sexual size dimorphism (SSD). Fecundity selection is often suggested as the main causal factor underlying the prevalence of female-biased SSD, but this assumption has not been empirically tested. I selected female Drosophila melanogaster for increased or decreased fecundity for 20 generations, and measured the effect on SSD in three morphological traits. SSD generally increased with selection for increased fecundity, but showed no consistent trend with selection for decreased fecundity. These results support the general hypothesis that SSD can evolve rapidly in response to selection for increased fecundity. SSD can evolve for a number of reasons. The two main causes are thought to be sexual selection on males, and natural selection favouring different trait optima in the two sexes. Lande (1980a,b) has produced analytical models that can be used for predicting the change in SSD through either of these mechanisms. Although these models are often cited, they have never been adequately tested, either empirically or through simulation modelling. They rely on a large number of simplifying assumptions, and their robustness to violations of these assumptions is largely unknown. In this thesis, I present results from stochastic simulation models designed to test the effects of mutational variance assumptions, finite populations, and finite numbers of loci on the robustness of the analytical models predictions. The quality of the predictions depends on the nature of allelic distributions in the original population. If allelic effects are approximately normally distributed, the predictions can be very accurate. If, as is likely, allelic effects have a leptokurtic distribution, Lande's equations underestimate the rate of response and correlated response, and overestimate the time required for the trait means to reach their equilibrium values. Predictions for the magnitude of SSD at equilibrium can be very accurate for weak sexual selection. However, with stronger sexual selection the total response is greater than predicted. The results suggest that genetic correlations constrain both the short-term and long-term evolution of SSD less than predicted by the Lande model.

碩士
東海大學
生物學系
90
In Taiwan, Rana kuhlii is the only anuran that has been described as the species that males are larger than females. But the reasons directly influence the phenomenon have not been studied yet. This study focuses on the population structure, longevity, gender differences in growth rate, and maturation ages of both sexes to examine the RSSD phenomenon and the relationships between these causes of R. kuhlii population in Lien-Hua-Chih in Nantou County. The study began on April 2000 and ended on September 2001. Mark-release method by toe clipping and the measurement of morphological parameters were performed for the frogs every month. We have marked 360 frogs, including 136 males, 105 females and 119 froglets that are sex-unknown. The average estimated population size of total, male and female frogs within the sampling area by Jolly-Seber method were 133, 59 and 47, respectively. During study period, the monthly fluctuations of population size, resident rate and recruitments of females were greater than those of males. From May to July in 2000 and from April to August in 2001, the sex ratios were extremely male-biased. Mean body sizes of males were not always larger than those of females from captured individuals whereas the biggest and oldest individuals in every month were male frogs. Age determination of 60 males and 37 females by skeletochronological method showed that one line of arrested growth (LAG) was equal to one year. The maximum ages of males were older than 7 years old and those of females were older than 6 years old. Population age structure established by ages estimated from size-age equation showed that 16.92﹪of males and 3.81﹪of females were older than 5 years old. And 11.02﹪ of male frogs were older and bigger than the oldest and biggest female. The mean maturation age of females was older than that of males. Males and females showed no differences in growth rate. In a word, the longer longevity of males was proposed to be one of the reasons leading to RSSD in R. kuhlii.

碩士
東海大學
生命科學系
98
Extreme female-biased sexual size dimorphism is generally assumed to result from female gigantism as a result of selection for fecundity in spiders. However, the mechanisms that maintain male’s smaller size are still not clear. The giant wood spiders Nephila pilipes is a species with extreme sexual size dimorphism, making it a suitable organism for studying which evolutionary pressures keep males in small body size. In this study, we performed field census and laboratory manipulations to realize potential sexual selection pressures on males of this species both before and after mating. Results of an intensive field census suggested that lager males could occupied a favorable position on a female’s web; however they might not obtain mating opportunities since males occupied the favorable position might not able to guard female for a long time and mate with the female at the right time which when female were molting. Also, most of mating events happened while there were only one male present on the web which means no male-male competition. N. pilipes have to travel for long distance to locate females. Since mate searching suffers high mortality risk, this might relax male-male competition in N. pilipes males and larger body size seems to be relatively unimportant under this circumstance. Results of field study thus indicate that how to find an appropriate female at the right time represents a strong selection pressure which favors protandry and small size in males. Results of laboratory manipulation showed that sperm competition pattern in N. pilipes followed a mixed rather than first male sperm priority pattern, suggesting a relatively weak post-copulatory sexual selection pressutr. Our field and laboratory studies thus show that selection pressures from pre-copulatory stage seem to be one important determinant of extreme sexual size dimorphism in N. pilipes.

碩士
國立成功大學
生命科學系
103
Sexual size dimorphism (SSD) describes divergent body sizes of adult males and females in a species. Several hypotheses (e.g., fecundity selection and sexual selection) have been proposed to explain evolution of SSD. Meanwhile, it has recently been acknowledged that SSD occurs because two sexes undergo different ontogenetic growth trajectories (i.e., growth rate and duration). However, it remains unclear how sex-specific ontogenetic growth trajectories evolve under sex-specific selection and life history trade-offs. To elucidate this, I develop a new theoretical framework by extending a quantitative genetic model for sexual trait dimorphism (i.e., male ornament) in which I reinterpret the trait as body size and redefine individual fitness in a size-dependent manner. Specifically, I assume that benefits of large body size are higher mating success for males and higher fecundity for females whereas accelerated growth rate and prolonged growth duration incur costs of lower survivorship and shorter reproduction period, respectively. Model analysis illustrated how two sexes would optimize ontogenetic growth trajectories under different trade-offs due to different reproductive strategies and divergent adult body sizes. The present framework incorporating an ontogenetic perspective provides a new insight into how SSD evolves, as well as testable hypotheses for empirical research.

The Fence Lizard (Sceloporus undulatus complex) is a wide ranging North American species complex occurring from the eastern seaboard westward through the great plains and central Rocky Mountains and into the American Southwest. A recent phylogeny suggests four species lineages occur within S. undulatus. Traits within an interbreeding species that are influenced by sexual selection are under different selection pressures and may evolve independently from the selective forces of habitat. Sceloporus lizards have several characters that are influenced by sexual selection. I investigated sexual size dimorphism and allometric relationships of body size (snout vent length), torso length, rear leg length and three measurements of head size in 12 populations from the four species in the S. undulatus complex (N=352) specifically looking for variation among the 4 species. Additionally I investigated the size of signal patches between males and females in three species (N=339 specimens of S. consobrinus, S. cowlesi, S. tristichus) of the S. undulatus complex. Sexual confusion, was recently described in a population of the Sceloporus undulatus complex occurring in White Sands, New Mexico and the behavior is correlated with variation in badge size between male and female lizards. To make inferences about sexual confusion at the species level I investigated the presence and absence of signal patches in female lizards, and compare the sizes of signal patches between males and females. My analyses suggest that torso length and head size are significant sources of sexual size dimorphism but the findings differ from earlier published investigations of sexually dimorphic characters in the species complex. I also find support for the S. undulatus complex being generally a female larger species complex. However two of the 12 populations I investigated displayed male biased sexual size dimorphism. Analysis of signal patches across three species of the S. undulatus complex suggests that sexual dimorphism in signal patch size for S. cowlesi and S. tristichus may not prevent sexual confusion. While the near total absence of signal patches in female S. consobrinus is evidence that sexual confusion is not possible with regards to signal patches.

A wide range of environmental and physiological factors influence the type and extent of sexual dimorphism found in animals. Influential factors include variable climate, competition for resources and mates, mate choice, and parental investment. In addition, some investigators attribute differences in body size to physiological factors influenced by genetic and environmental variation. Since Darwin's time researchers studying the evolution of animal life-history have discussed the interactions that exist between this wide array of influences on sexual dimorphism in the context of natural selection. Much attention has been paid to the interrelationships of parental size, offspring size and number of offspring per reproductive bout. Spatial and temporal variation among these parameters have been investigated. However, these relationships have not been adequately examined while accounting for differences in offspring gender. In order to characterize the nature and extent of sexual size dimorphism found in adult red-spotted garter snakes, 108 adult females producing 782 female offspring and 790 male offspring were utilized to examine the relationships of the number and size of offspring, clutch mass and maternal size. The second facet of our investigation involved the hormonal manipulation of growth over the first year of post-natal life. To gain an understanding of which endogenous hormones may influence growth in this species we constructed a hormone profile of estradiol and testosterone from birth to 15 weeks of age. We experimentally tested the effects of exogenous hormone as well as the removal of endogenous hormone on growth with the use of estrogen and androgen antagonists. We have found that the extent of sexual size dimorphism observed in adult red-spotted garter snakes is not present at birth. The relative number of males or females born varies differentially with maternal size and age such that larger, older females produce predominately more male offspring. There are no differences in endogenous levels of testosterone and estradiol from birth though 15 weeks and at 36 weeks of age between the sexes. However, these sex steroids do differentially affect the growth of males and females. Finally, we suggest that while all of these factors contribute to sexual size dimorphism in this species, embryonic and environmental influences need to be explored.
Graduation date: 1999

I describe the natural history and reproductive behaviours of the Emei Moustache Toad (Leptobrachium boringii), testing the hypotheses that the species exhibits resource defense polygyny, and that combat, and paternal care lead to the evolution of male-biased sexual size dimorphism. In this study I document combat behaviour and paternal care for the first time in this species. Between February and March of 2011 and 2012, 26 female and 55 male L. boringii from Mount Emei UNESCO World Heritage Site, Sichuan, China, were observed throughout the breeding season. Prior to the breeding season, males grow 10-16 keratinized maxillary spines, which fall off once the season has ended. Throughout this time, males construct and defend aquatic nests where they produce advertisement calls to attract females. In a natural setting, I documented 14 cases involving a total of 22 males where males used their moustaches for aggressive interaction, and nest take over was observed on seven occasions. Despite my predictions, neither male body size nor body condition significantly affects the outcome of an aggressive interaction, though this may be representative of a low sample size. Males were also observed to possess injuries resulting from combat. Combat trials conducted in artificial nests demonstrated heightened aggression from resident males towards intruders. Genetic analysis using microsatellite markers revealed several cases of multiple paternity, both within nest and within clutch, indicating that some alternative male reproductive strategy, such as satellite behaviour is occurring. Larger males were observed to mate more frequently, and in multiple nests, suggesting that females are selecting for larger males, or that larger males are more capable of defending high quality territories. Males showed evidence of paternal care behaviours by remaining with the nests once females had left, moving throughout the nest cleaning, touching the eggs, and blowing bubbles into the centre of the doughnut-shaped egg masses. From this study I conclude that the male biased sexual size dimorphism in L. boringii is likely the result of both combat and paternal care behaviours creating a selection pressure on male body size.

abstract: Early hominins present an unusual pattern of sexual dimorphism. On one hand, the canine teeth of these species are weakly size-dimorphic, vertically short, and nonhoning, suggesting a social system characterized by infrequent, low-intensity intermale competition and monogamous pair-bonding. On the other hand, marked size variation in skeletal remains attributed to species of Australopithecus is thought to reflect strong body-mass dimorphism, which is more consistent with intense intermale competition. Reconciling these conflicting signals and understanding their adaptive significance is a major goal of paleoanthropology. This dissertation research contributes to this objective by investigating factors that may constrain or reduce canine height in extant anthropoid primates. Two hypotheses regarding the relationship between canine height and other elements of the masticatory system were tested using phylogenetic comparative methods. According to the first hypothesis, canine reduction is a pleiotropic by-product of changes in the sizes of other components of the dentition. With respect to canine height, the results of this study fail to support this idea. There is limited evidence for a relationship between basal canine crown dimensions and incisor and postcanine size, but significant interspecific correlations between these variables are not strong and are restricted primarily to the female maxillary dentition. These results indicate that if pleiotropy influences canine size, then its effects are weak. The second hypothesis proposes that canine reduction is a consequence of selection for increased jaw-muscle leverage. This hypothesis receives some support: there is a clear inverse relationship between canine height and the leverage of the masseter muscle in male anthropoids. Females do not exhibit this association due to the fact that dimorphism in muscle leverage is weak or absent in most anthropoid species; in other words, female muscle leverage tracks male muscle leverage, which is linked to canine height. Leverage of the temporalis muscle is not correlated with canine height in either sex. Two specimens of the 3.0-3.7-million-year-old hominin Australopithecus afarensis fall at or beyond the upper end of the great ape range of variation in masseter leverage, which is consistent with the idea that hominin canine evolution was influenced by selection for increased jaw-muscle leverage.
Dissertation/Thesis
Ph.D. Anthropology 2010

Dissertação de Mestrado em Quaternario e pré-história
Embora se conheçam muitos artigos publicados sobrea anatomia e sistemática do cavalo do Quaternário,a história de alguns Equus mostra a falta de alguns elos de ligação  na  história natural do cavalo. No presente trabalho pretende‐se fazer uma tentativa de classificar Cavalos (discriminar entre espécies ou grupo de espécies), com base no tamanho, sexo e forma, com em dois métodos estatísticos. Os objectivos são traçar o racio sexual e estabelecer o grau de dimorfismo sexual nos fósseis de cavalos da península italian; caracterizar a estrutura dos ossos do cavalo, com base no tamanho e forma do Pleistoceno ao Holoceno, com a ajuda da análise e Mistura Principal de componentes de analises. Em conclusão, podemos dizer que a razão sexual está situada entre 68% ‐32% aproximadamente, e também que quase não existe uma separação clara entre os dados dos fósseis, (não são sobrepostos uns aos outros, excepto os Dados de Eisenmann, que são heterogénios) utilizados no presente trabalho, na análise do tamanho e formato, o que indica três factores que podem ser os que têm diferentes taxonomía e cronología e diferentes condições ambientais. O presente trabalho é apenas uma tentativa de estudo dos Equinos.
Although so many articles have been published about the anatomy and systematic of Quaternary horse but still the story of Equus showing some missing links between the natural history of horse. In this present work applicant make an attempt to classify Horses (discriminate between species or group of species) on the basis of Size, Sex and shape analysis with using two Multivariate statistical methods. The objectives is two trace out the sex ratio, and establish degree of sexual dimorphism in fossil horses from Italian peninsula; to characterized the structure of horse bones on the basis of size and shape analysis occurs from Pleistocene to Holocene with the help of Mixture analysis and Principal Component Analysis. In the conclusion, one can say that the sex ratio is lying between 68%-32% approximately and also there is almost clear separation between the fossil data have been (they are not overlapping each other except Eisenmann Data which is a heterogeneous one) used in the present work in Size and Shape analysis, which indicating three factors that may be they have different taxonomy, different chronology and different environmental conditions. This present work is just a primarily attempt in Equine studies.

There is a large amount of evidence that the demography and associated life history features of coral reef fish vary across a range of spatial scales. Many Indo-Pacific species are particular in that their geographical distribution extends over ocean basins, and there is increasing evidence that a number of coral reef fish display highly asymptotic growth trajectories. This thesis uses an age-based approach to examine the mechanisms and patterns of variation in the demography and associated life history features over broad geographical scales and in the context of asymptotic growth, exploring the nature of the trade-offs in life history traits associated with variation in growth in coral reef fish. Over 1500 individuals of three Acanthurid species, Ctenochaetus striatus, Acanthurus nigricans and Acanthurus leucosternon, were collected at 14 locations across the Indo-Pacific region. Three critical demographic parameters were examined: mean adult body size, growth rate and longevity, and the relationship between size, age and sex was established using the re-parameterised equation of the Von Bertalanffy Growth Function. We found a longitudinal trend in life span, with Indian Ocean populations being shorter lived than those of the Pacific region, suggesting the presence of differences in population dynamics and recruitment patterns between ocean basins. In contrast, there was no predictable pattern in growth, which varied primarily across locations indicating a substantial effect on growth of local habitat conditions. There was a clear sex-specific structure in growth within all populations sampled. The mechanism underlying the variation in size among and within populations was a mechanism of fast initial growth, which was consistent across species, geographical scales, and across the sexes. This result indicates that adult body size is determined by the rate of growth during the early years of post-settlement life of all individuals, regardless of the nature of sexual ontogeny, suggesting the absence of a trade-off between reproductive and somatic growth in both males and females of the study species. The magnitude of the differences in size between the sexes increased in populations where large absolute adult size was favoured, suggesting an allometric relationship between sexual size dimorphism and the rate of growth of the larger sex. The direction of sexspecific size distributions of the study species varied with adult body size of males, providing evidence that female-biased sexual size dimorphism in acanthurid species is the result of selection for small body size in males. This study illustrates the importance of early post-settlement life history in shaping the demography and life histories in coral reef fish with a highly asymptotic form of growth, and suggests that determinate growth is associated with: 1) a large potential for flexibility in growth, 2) constraints on the nature of the mechanisms underlying variation in size across geographical scales, and between the sexes, and 3) an evolutionary life history trade-off between juvenile survival and lifetime reproductive success overriding the costs of reproductive growth of females.

There is a large amount of evidence that the demography and associated life history features of coral reef fish vary across a range of spatial scales. Many Indo-Pacific species are particular in that their geographical distribution extends over ocean basins, and there is increasing evidence that a number of coral reef fish display highly asymptotic growth trajectories. This thesis uses an age-based approach to examine the mechanisms and patterns of variation in the demography and associated life history features over broad geographical scales and in the context of asymptotic growth, exploring the nature of the trade-offs in life history traits associated with variation in growth in coral reef fish. Over 1500 individuals of three Acanthurid species, Ctenochaetus striatus, Acanthurus nigricans and Acanthurus leucosternon, were collected at 14 locations across the Indo-Pacific region. Three critical demographic parameters were examined: mean adult body size, growth rate and longevity, and the relationship between size, age and sex was established using the re-parameterised equation of the Von Bertalanffy Growth Function. We found a longitudinal trend in life span, with Indian Ocean populations being shorter lived than those of the Pacific region, suggesting the presence of differences in population dynamics and recruitment patterns between ocean basins. In contrast, there was no predictable pattern in growth, which varied primarily across locations indicating a substantial effect on growth of local habitat conditions. There was a clear sex-specific structure in growth within all populations sampled. The mechanism underlying the variation in size among and within populations was a mechanism of fast initial growth, which was consistent across species, geographical scales, and across the sexes. This result indicates that adult body size is determined by the rate of growth during the early years of post-settlement life of all individuals, regardless of the nature of sexual ontogeny, suggesting the absence of a trade-off between reproductive and somatic growth in both males and females of the study species. The magnitude of the differences in size between the sexes increased in populations where large absolute adult size was favoured, suggesting an allometric relationship between sexual size dimorphism and the rate of growth of the larger sex. The direction of sexspecific size distributions of the study species varied with adult body size of males, providing evidence that female-biased sexual size dimorphism in acanthurid species is the result of selection for small body size in males. This study illustrates the importance of early post-settlement life history in shaping the demography and life histories in coral reef fish with a highly asymptotic form of growth, and suggests that determinate growth is associated with: 1) a large potential for flexibility in growth, 2) constraints on the nature of the mechanisms underlying variation in size across geographical scales, and between the sexes, and 3) an evolutionary life history trade-off between juvenile survival and lifetime reproductive success overriding the costs of reproductive growth of females.