Articoli di riviste: "Marsupialia Reproduction"

1

Kitchener, DJ, N. Cooper e a. Bradley. "Reproduction in Male Ningaui (Marsupialia, Dasyuridae)". Wildlife Research 13, n. 1 (1986): 13. http://dx.doi.org/10.1071/wr9860013.

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Abstract (sommario):

'Stages in the spermatogenic cycle of Ningaui ridei, N. yvonneae and N. timealeyi are defined and the phenology of these stages is presented. In males of Ningaui spp. sexual maturity is reached in the first year, such that after the end of July of each year almost all male Ningaui spp. are considered reproductively mature. Male Ningaui spp. in the active spermatogenic phase are found during the entire season of births (August-January in N. ridei and N. timealeyi but perhaps terminating earlier in N. yvonneae); testes regress to an immature spermatogenic stage after January. There is no indication that in the field adult males die immediately following mating.

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2

Nelson, JE, e A. Goldstone. "Reproduction in Peradorcas-Concinna (Marsupialia, Macropodidae)". Wildlife Research 13, n. 4 (1986): 501. http://dx.doi.org/10.1071/wr9860501.

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The length of the oestrous cycle in captive Peradorcas concinna was 33.73 � 1.65 days (n = 52). Females which were dominant over other females or were alone with their young had a cycle length of about 32 days and subordinate females had a cycle length of about 35 days. Some observations on the growth of the young are presented. Weaning is very abrupt; final pouch exit occurs about 2 weeks after the first pouch exit, and is caused by the female's aggressiveness towards its young.

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3

Woolley, PA, e A. Valente. "Reproduction in Sminthopsis-Longicaudata (Marsupialia, Dasyuridae) - Laboratory Observations". Wildlife Research 13, n. 1 (1986): 7. http://dx.doi.org/10.1071/wr9860007.

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Abstract (sommario):

Observations on the pattern of reproduction in Sminthopsis longicaudata, at present considered to be an endangered species, are presented. S. longicaudata is polyoestrous and in the laboratory females are in breeding condition from late winter (August) to early summer (December). They enter oestrus up to four times during the breeding season. Two litters were born 17 and 19 days post-mating, but the gestation period may be less than 15 days. The mean length of the oestrous cycle is 34.4 days. Both males and females may be able to breed in more than one season.

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4

Woolley, PA. "Reproduction in Dasykaluta-Rosamondae (Marsupialia, Dasyuridae) - Field and Laboratory Observations". Australian Journal of Zoology 39, n. 5 (1991): 549. http://dx.doi.org/10.1071/zo9910549.

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Observations on reproduction in both wild-caught and laboratory-maintained Dasykaluta rosamondae have led to the conclusion that this species is one of 10 dasyurid marsupials in which males die soon after their first mating period. D. rosamondae have a short annual breeding season. The females are monoestrous, mating in September and bearing the young in November. Laboratory-reared young are weaned at an age of about 3 1/2-4 months, in February and March, and juveniles appear in the field population at this time. Both mates and females reach sexual maturity at an age of about 10 months. In the laboratory, males breed in only one season, after which those that survive become reproductively senile. Mature males disappear from the field population about the time the young are born; those collected shortly before this show signs of reproductive senescence. Males collected in the months after the young are weaned represent a single age-class; their reproductive development parallels that of maturing known-age males. Females are capable of breeding in at least two seasons and litters of up to eight are reared. Development of the pouch young is described. Unusual interstitial tissue masses develop in the ovaries of D. rosamondae; the granulosa cells of some follicles undergo transformation to interstitial cells, and the oocytes in these follicles degenerate, shortly before the females enter oestrus.

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5

Hogan, Lindsay A., Tina Janssen e Stephen D. Johnston. "Wombat reproduction (Marsupialia; Vombatidae): an update and future directions for the development of artificial breeding technology". REPRODUCTION 145, n. 6 (giugno 2013): R157—R173. http://dx.doi.org/10.1530/rep-13-0012.

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This review provides an update on what is currently known about wombat reproductive biology and reports on attempts made to manipulate and/or enhance wombat reproduction as part of the development of artificial reproductive technology (ART) in this taxon. Over the last decade, the logistical difficulties associated with monitoring a nocturnal and semi-fossorial species have largely been overcome, enabling new features of wombat physiology and behaviour to be elucidated. Despite this progress, captive propagation rates are still poor and there are areas of wombat reproductive biology that still require attention, e.g. further characterisation of the oestrous cycle and oestrus. Numerous advances in the use of ART have also been recently developed in the Vombatidae but despite this research, practical methods of manipulating wombat reproduction for the purposes of obtaining research material or for artificial breeding are not yet available. Improvement of the propagation, genetic diversity and management of wombat populations requires a thorough understanding of Vombatidae reproduction. While semen collection and cryopreservation in wombats is fairly straightforward there is currently an inability to detect, induce or synchronise oestrus/ovulation and this is an impeding progress in the development of artificial insemination in this taxon.

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6

Wooley, P. A. "Observations on Reproduction in Captive Parantechinus biiarni (Marsupialia: Dasyuridae)". Australian Mammalogy 18, n. 1 (1995): 83. http://dx.doi.org/10.1071/am95083.

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7

WARD, S. J., e M. B. RENFREE. "Reproduction in females of the feathertail gliderAcrobates pygmaeus(Marsupialia)". Journal of Zoology 216, n. 2 (ottobre 1988): 225–39. http://dx.doi.org/10.1111/j.1469-7998.1988.tb02427.x.

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8

WARD, S. J., e M. B. RENFREE. "Reproduction in males of the feathertail gliderAcrobates pygmaeus(Marsupialia)". Journal of Zoology 216, n. 2 (ottobre 1988): 241–51. http://dx.doi.org/10.1111/j.1469-7998.1988.tb02428.x.

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9

Woolley, PA. "Reproduction in Sminthopsis-Macroura (Marsupialia, Dasyuridae) .1. The Female". Australian Journal of Zoology 38, n. 2 (1990): 187. http://dx.doi.org/10.1071/zo9900187.

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Abstract (sommario):

A laboratory colony of S. macroura, founded by three females and four males, was maintained over four breeding seasons. Reproductive success was high and four generations were produced before the colony was disbanded. Descendants of these animals are still breeding in another laboratory 11 years after the founding of the colony. A detailed prescription for the maintenance and management of a breeding colony is given. The animals bred between June and February, most females first entering oestrus in the early months of the season, in July or August. Female young born early in the season (before mid-October) matured in the season of their birth at an age of 86-159 days; those born later matured in the following season at an age of 185-262 days. In each group, those born later matured earlier. Minimum body weight at sexual maturity was 12.5 g. At least two litters can be reared in a season and individuals may breed in more than one season. S. macroura is polyoestrous with a mean cycle length of 23.25 days. The gestation period is about 11 days and up to eight young can be accommodated in the pouch. Lactating females may return to oesrrus up to 10 days before the young are weaned at 70 days old. Ovulation occurs spontaneously and the mean number of corpora lutea formed was 20.7. The corpora lutea reach maximal size late in pregnancy and they regress more rapidly in lactating than in non- lactating females. Up to three generations of corpora lutea could be recognised in the ovaries of females undergoing cycles uninterrupted by lactation. Changes In body weight, the pouch, and the gross and histological appearance of the reproductive tract were the same in pregnant and pseudopregnant females.

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10

Woolley, PA. "Reproduction in Sminthopsis-Macroura (Marsupialia, Dasyuridae) .2. The Male". Australian Journal of Zoology 38, n. 2 (1990): 207. http://dx.doi.org/10.1071/zo9900207.

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Abstract (sommario):

The breeding season of S. macroura extends from June to February, and individual males (both wild- caught and laboratory-reared) are capable of breeding over extended periods during the breeding season, and for up to three seasons, in the laboratory. Gross and histological changes in the reproductive organs and endocrine changes in relation to reproductive activity have been investigated. Males do not appear to reach sexual maturity until the season following that in which they were born, although spermatorrhoea may commence in the season of birth. Testis and epididymis weight of these males, which commence spermatorrhoea late in the season, approximates that of sexually mature males early in the season but androgen levels and the weight of the accessory glands are low in all males except during the early months of the season. The age at which spermatorrhoea commences ranges from 141 to 350 days. The minimum scrota1 width at which it commences is 7.9 mm and the minimum body weight, 14.0 g. The onset of spermatorrhoea is not a function of age or season and in S. macroura should be used with caution as an indicator of impending sexual maturity. Maximum corticosteroid- binding capacity (MCBC) generally exceeded corticosteroid concentration and no androgen-related fall in MCBC was evident.

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11

Woolley, PA. "Reproduction in Pseudantechinus macdonnellensis (Marsupialia : Dasyuridae): Field and Laboratory". Wildlife Research 18, n. 1 (1991): 13. http://dx.doi.org/10.1071/wr9910013.

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Abstract (sommario):

Pseudantechinus macdonnellensis has a wide distribution within the arid zone of Australia. Observations have been made on reproduction in both newly captured and laboratory-maintained animals obtained from widely separated localities. They have a short annual breeding season; animals from the more westerly part of the range breed later in the year. Males are potentially capable of breeding in at least three seasons, and females in at least four. Females are monoestrous and the gestation period, timed from mating to birth, is from 45 to 55 days. The young are suckled for about 14 weeks in the laboratory and are capable of breeding in the season following that in which they were born, when they are approaching 1 year of age.

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12

Wilson, BA. "Reproduction in the Female Dasyurid Antechinus-Minimus-Maritimus (Marsupialia, Dasyuridae)". Australian Journal of Zoology 34, n. 2 (1986): 189. http://dx.doi.org/10.1071/zo9860189.

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Abstract (sommario):

Reproduction in female Antechinus minimus maritimus was investigated in the field and laboratory. Field data were obtained from a mark-recapture study. A laboratory colony was maintained to investigate the oestrous pattern, length of gestation and development of pouch young. Breeding occurred in winter with births in July or August. Gestation (mean � SD) was 30.6 � l.5 days for animals mated in the laboratory. Epithelial cells were present in the urine for 34.8 � 8.3 days, a lengthy period compared to A. stuartii (19.3 � 4.4 days). Ovaries from females before the breeding season contained small developing follicles. During the breeding season Graafian follicles (4-8 per ovary) or corpora lutea (4-13 per ovary) were found. Reproduction in A. m. maritimus females is similar to that described previously in other Antechinus.

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13

Kerle, JA, e CJ Howe. "The Breeding Biology of a Tropical Possum, Trichosurus-Vulpecula-Arnhemensis (Phalangeridae, Marsupialia)". Australian Journal of Zoology 40, n. 6 (1992): 653. http://dx.doi.org/10.1071/zo9920653.

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Abstract (sommario):

The breeding biology of Trichosurus vulpecula has been studied in some detail for temperate populations but not for the northern brushtail possum (T. v. arnhemensis), the tropical form of this species. Data for the distribution of births and sex ratio of the young, growth and development of the young and reproductive cycles of both males and females were obtained. Most data were collected from a captive breeding colony of northern brushtails and supplemented with data from wild populations. The reproduction, growth and development of T. v. arnhemensis are very similar to those already described for other populations of T vulpecula. The observed differences can be explained by variation in the size of the animals and the absence of a restricted breeding season. Neither males nor females showed any periodicity in their reproductive strategy. This continuous breeding cycle can be attributed directly to their tropical environment. These tropical possums occupy a stable habitat, mature early and have a higher reproductive effort than populations in more seasonal and unpredictable environments. This suggests that the northern brushtail has a stochastic or 'bet-hedging' reproductive strategy.

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14

Ward, SJ. "Reproduction in the Western Pygmy-Possum, Cercartetus-Concinnus (Marsupialia, Burramyidae), With Notes on Reproduction of Some Other Small Possum Species". Australian Journal of Zoology 38, n. 4 (1990): 423. http://dx.doi.org/10.1071/zo9900423.

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The patterns of breeding and reproduction in Cercartetus concinnus were investigated through the histology of specimens in Australian museums, field observations in north-western Victoria, and published accounts. Histology of the reproductive tracts of museum specimens of female C. nanus, C. lepidus, Acrobates pygmaeus and Distoechurus pennatus was also undertaken to elaborate on reproduction in these species. Young of C. concinnus are born in most months, and some reproductively active males are probably present at all times of the year. Embryonic diapause occurs during the unilaminar blastocyst stage of embryonic development; the blastocysts expand slowly during diapause. The presence of embryos in the uteri of lactating female D. pennatus and C. lepidus suggests that diapause is also probable in these species. The gross anatomies of the female reproductive tracts of the five small possum species are described. Cercartetus spp. have a vaginal system characterised by voluminous culs-de-sac, and only vestigial remains of a median septum. This contrasts with the condition in the two acrobatids, in which the vaginal culs-de-sac are smaller and divided by a prominent septum. The male reproductive anatomy of C. concinnus is similar to that of C. lepidus. The prostate is carrot-shaped and its internal structure is unlike that described for other marsupial groups.

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15

McAllan, B. M., e F. Geiser. "Photoperiod and the timing of reproduction in Antechinus flavipes (Dasyuridae: Marsupialia)". Mammalian Biology 71, n. 3 (maggio 2006): 129–38. http://dx.doi.org/10.1016/j.mambio.2006.01.005.

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16

Woolley, PA. "Reproduction in the Ningbing Antechinus (Marsupialia, Dasyuridae) - Field and Laboratory Observations". Wildlife Research 15, n. 2 (1988): 149. http://dx.doi.org/10.1071/wr9880149.

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Abstract (sommario):

The ningbing antechinus is a species of small dasyurid marsupial found in the Kimberley region of Western Australia. Observations on reproduction have been made on newly captured and laboratory maintained specimens. The breeding season is short and mating occurs in June. The young are born after a long gestation, estimated to be between 45 and 52 days, in late July and early August. They are weaned in November when about 16 weeks old and they reach sexual maturity at 10-11 months, in the first breeding season after birth. Both males and females are potentially capable of breeding in a second season.

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17

Cummins, J. M., P. D. Temple-Smith e M. B. Renfree. "Reproduction in the male honey possum (Tarsipes rostratus: Marsupialia): The epididymis". American Journal of Anatomy 177, n. 3 (novembre 1986): 385–401. http://dx.doi.org/10.1002/aja.1001770308.

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18

Geiser, Fritz, e Pip Masters. "Torpor in relation to reproduction in the mulgara, Dasycercus cristicauda (Dasyuridae: Marsupialia)". Journal of Thermal Biology 19, n. 1 (febbraio 1994): 33–40. http://dx.doi.org/10.1016/0306-4565(94)90007-8.

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19

Woolley, P. A. "Aspects of reproduction, and morphology of the penis, of Pseudantechinus woolleyae (Marsupialia : Dasyuridae)". Australian Journal of Zoology 65, n. 6 (2017): 357. http://dx.doi.org/10.1071/zo17086.

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Abstract (sommario):

Woolley’s Pseudantechinus, P. woolleyae, has remained virtually unstudied in the 30 years since its recognition in 1988 as a species distinct from P. macdonnellensis. It has a wide distribution in arid regions of Western Australia. What little is known of its biology comes largely from studies carried out over the years 1988–91 on one wild-caught female and her offspring, and a few specimens held in the collection of the Western Australian Museum. P. woolleyae is a seasonal breeder and young are born from late July to early October. They mature when ~7 months old. Both males and females are potentially capable of breeding in more than one year. Males have accessory erectile tissue that does not form an appendage on the penis.

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20

Johnson, P. M. "Reproduction in the Bridled Nailtail Wallaby, Onychogalea fraenata Gould (Marsupialia : Macropodidae), in Captivity". Wildlife Research 24, n. 4 (1997): 411. http://dx.doi.org/10.1071/wr96028.

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The reproduction of the endangered macropod Onychogalea fraenata was studied in captivity. O. fraenata breeds throughout the year. A post-partum oestrus was not recorded, although mating during the pouch life was observed when the pouch young were 80–92 days old. The mean length of the oestrous cycle was determined to be 36·2 days, while the mean length of a gestation period was 23·6 days. Pouch life ranged between 119 and 126 days, and the young males and females matured as early as 270 days and 136 days, respectively.

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21

Johnson, PM. "Reproduction of the spectacled hare-wallaby, Lagorchestes conspicillatus Gould (Marsupialia: Macropodidae), in captivity, with age estimation of the pouch young". Wildlife Research 20, n. 1 (1993): 97. http://dx.doi.org/10.1071/wr9930097.

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Lagorchestes conspicillatus has a widespread distribution across northern Australia. Observations were made on reproduction in captive animals and a key produced for age determination of pouch young. Females commence breeding at about one year of age and males when slightly older. Reproduction in this species involved an oestrous cycle of 30 days, a gestation period of 29-31 days and a mean pouch life of 152 days. A postpartum oestrus and mating following a birth was the normal pattern of reproduction.

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22

Dickman, CR, DH King, M. Adams e PR Baverstock. "Electrophoretic Identification of a New Species of Antechinus (Marsupialia, Dasyuridae) in Southeastern Australia". Australian Journal of Zoology 36, n. 4 (1988): 455. http://dx.doi.org/10.1071/zo9880455.

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Two electrophoretically distinct but morphologically cryptic forms of Antechinus 'stuartii', designated 'northern' and 'southern', occur together at Kioloa on the southern coast of New South Wales. These forms are distinguished by fixed allele differences in three proteins (albumin, glycollate oxidase and mannosephosphate isomerase) and by differences in allele frequencies for transferrin, and are separated by a Nei D of 0.11. The two forms are reproductively isolated in sympatry at Kioloa by asynchrony in the timing of reproduction, and may be considered separate biological species. Northern form populations were identified by screening for albumin and transferrin in seven localities on the central coast of New South Wales north of Kioloa. Southern form populations were identified similarly in 13 localities south of Kioloa and inland along the Great Dividing Range, and at a further locality in southern Victoria. Ovulation occurs at different rates of change of photoperiod in the two species, and may ensure that reproductive isolation is maintained in all potential areas of sympatry. The northern form represents A. stuartii sensu stricto and ranges from Kioloa north into south-eastern Queensland. The southern form is an undescribed species of Antechinus that appears to be widely distributed throughout southern New South Wales and Victoria.

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23

Renfree, Marilyn B. "Society for Reproductive Biology Founders' Lecture 2006 Life in the pouch: womb with a view". Reproduction, Fertility and Development 18, n. 7 (2006): 721. http://dx.doi.org/10.1071/rd06072.

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Abstract (sommario):

Marsupials give birth to an undeveloped altricial young after a relatively short gestation period, but have a long and sophisticated lactation with the young usually developing in a pouch. Their viviparous mode of reproduction trades placentation for lactation, exchanging the umbilical cord for the teat. The special adaptations that marsupials have developed provide us with unique insights into the evolution of all mammalian reproduction. Marsupials hold many mammalian reproductive ‘records’, for example they have the shortest known gestation but the longest embryonic diapause, the smallest neonate but the longest sperm. They have contributed to our knowledge of many mammalian reproductive events including embryonic diapause and development, birth behaviour, sex determination, sexual differentiation, lactation and seasonal breeding. Because marsupials have been genetically isolated from eutherian mammals for over 125 million years, sequencing of the genome of two marsupial species has made comparative genomic biology an exciting and important new area of investigation. This review will show how the study of marsupials has widened our understanding of mammalian reproduction and development, highlighting some mechanisms that are so fundamental that they are shared by all today’s marsupial and eutherian mammals.

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24

Woolley, PA. "Reproductive Pattern of Captive Boullanger Island Dibbers, Parantechinus apicalis (Marsupialia : Dasyuridae)". Wildlife Research 18, n. 2 (1991): 157. http://dx.doi.org/10.1071/wr9910157.

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The recent discovery in Western Australia of two island populations of the dibbler, Parantechinus apicalis, which is rare on the mainland, has provided an opportunity for further study of this species. Following the finding that all males in an island population died soon after the mating period in March, in contrast to mainland males which survive beyond their first breeding season in both the field and the laboratory, a study of the pattern of reproduction in captive island dibblers was made. Like mainland dibblers, island females were found to be monoestrous, and island males potentially capable of breeding in more than one season. Island dibblers are smaller than mainland dibblers but the estimated length of pseudopregnancy was found to be similar. The results of the study on captive island dibblers, together with observations made on the island population at the time it was discovered, suggest that the 'die-off' of males observed in each of the three years following their discovery may not be an inevitable event, as it is for the males of some other species of small dasyurid marsupials (e.g. Antechinus).

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25

Martins, Eduardo Guimarães, Vinícius Bonato, Cibele Queiroz da-Silva e Sérgio Furtado dos Reis. "Seasonality in reproduction, age structure and density of the gracile mouse opossum Gracilinanus microtarsus (Marsupialia: Didelphidae) in a Brazilian cerrado". Journal of Tropical Ecology 22, n. 4 (luglio 2006): 461–68. http://dx.doi.org/10.1017/s0266467406003269.

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Abstract (sommario):

The temporal pattern of reproduction and its consequences for age structure and density were investigated in a population of the gracile mouse opossum Gracilinanus microtarsus in south-eastern Brazil. Individuals of G. microtarsus were monitored through capture–mark–recapture methods from August 2000 to February 2003 in a remnant of cerradão, a forest-like physiognomy of the highly seasonal cerrado biome. The temporal pattern of reproduction of the population studied was highly seasonal with rearing of the offspring occurring in the first half of the warm-wet season, when the abundance of food resources – primarily insects – in the cerrado is high. Shortly after reproduction, the density of adults decreased sharply, possibly because of high post-mating mortality, leading to a gradual replacement of adults by their offspring in the following months and little overlap of generations. Our data suggest that climatic and environmental factors affect the onset of reproduction and interact with endogenous factors that decrease post-mating survival to produce the observed pattern of seasonal variation in age structure and density. It is suggested that the dynamics of populations of G. microtarsus may be driven primarily by food limitation and that long-term studies are needed to understand its feedback structure.

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26

Watt, Annemarie. "Population Ecology and Reproductive Seasonality in Three Species of Antechinus (Marsupialia : Dasyuridae) in the Wet Tropics of Queensland". Wildlife Research 24, n. 5 (1997): 531. http://dx.doi.org/10.1071/wr96033.

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Abstract (sommario):

The population and reproductive ecologies of three sympatric species of antechinus were examined in upland rainforests in the wet tropics of Queensland. The three species, Antechinus stuartii adustus, A. flavipes rubeculus and A. godmani, exhibited unusually low trapping success compared with that of sites in temperate regions of Australia. Spatial distributions were extremely patchy both between and within study sites. Comparison with trapping data for temperate populations of A. stuartii and A. flavipes suggests that densities in the wet tropics are among the lowest in Australia. The reproductive season was similar for the three species, commencing during the mid-dry season with juveniles weaned by the early to mid-wet season. The phenomenon of male die-off was observed in the three species. However, the highly synchronous two- week breeding season observed in temperate populations of A. stuartii and A. flavipes was not observed in the tropical populations. The breeding season of the tropical species extended over a six- week period. Timing of reproduction in A. s. adustus and A. f. rubeculus was more similar to temperate than to subtropical populations of A. s. stuartii and A. f. flavipes.

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27

Friend, G. R., B. W. Johnson, D. S. Mitchell e G. T. Smith. "Breeding, Population Dynamics and Habitat Relationships of Sminthopsis dolichura (Marsupialia : Dasyuridae) in Semi-arid Shrublands of Western Australia". Wildlife Research 24, n. 3 (1997): 245. http://dx.doi.org/10.1071/wr96070.

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Abstract (sommario):

Demographic data were gathered from two populations of the little long-tailed dunnart, Sminthopsis dolichura, inhabiting semi-arid nature reserves in the Western Australian wheatbelt in order to place the ecology of this species (formerly part of the Sminthopsis murina complex) in perspective. In all respects, S. dolichura is similar to S. murina from south-eastern Australia, and, indeed, to most other species of the Sminthopsis group. High mobility and transiency rates, an extended seasonal pattern of reproduction, relatively rapid development of the young and the probable existence of polyoestry characterise the life history of S. dolichura and most other species within the group that have been studied. These attributes enable a high degree of reproductive flexibility and permit these species to opportunistically invade new habitats and ephemeral post-fire seral stages. The observed sympatry with highly seasonal monoestrous dasyurids of the genus Antechinus is postulated to occur through spatial and temporal selection of different microhabitats, but also suggests that phylogenetic factors may be at least as important as the predictability of climate and food resources in explaining the evolution of different reproductive strategies.

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28

Johnson, PM, e K. Vernes. "Reproduction in the red-legged pademelon, Thylogale stigmatica Gould (Marsupialia : Macropodidae), and age estimation and development of pouch young". Wildlife Research 21, n. 5 (1994): 553. http://dx.doi.org/10.1071/wr9940553.

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Abstract (sommario):

The reproduction of Thylogale stigmatica in captivity was studied and a predictive growth equation for age determination of the pouch young was developed. The general pattern of reproduction involved an oestrous cycle of 29-32 days, a gestation period of 28-30 days and a mean pouch life of 184 days. A post-partum oestrus and mating generally followed birth. Births were observed in all months in captivity, and from October to June in the wild. Mean age of weaning of young was 66 days following permanent pouch emergence, and the mean ages at maturity for females and males was 341 and 466 days, respectively.

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29

Crowther, M. S., P. B. S. Spencer, D. Alpers e C. R. Dickman. "Taxonomic status of the mardo, Antechinus flavipes leucogaster (Marsupialia : Dasyuridae): a morphological, molecular, reproductive and bioclimatic approach". Australian Journal of Zoology 50, n. 6 (2002): 627. http://dx.doi.org/10.1071/zo02030.

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Abstract (sommario):

This paper uses a combined morphological, molecular and ecological approach to assess the taxonomic status of Antechinus flavipes leucogaster from Western Australia, and its relationship to A. flavipes flavipes from eastern Australia. Morphological analyses show that A. flavipes leucogaster is smaller and finer than its eastern Australian counterpart in both cranial and dental dimensions. Phylogenetic analyses of partial cytochrome-b sequences showed that A. flavipes flavipes and A. flavipes leucogaster form reciprocally monophyletic clades that have a relatively high level of divergence (approximately 6%). Analysis of the timing of reproduction indicates that the two subspecies show opposite responses to latitude, with A. flavipes leucogaster ovulating later at high latitudes and A. flavipes flavipes ovulating later in more northerly parts of its range. The combined data and the entirely allopatric distributions of the two subspecies confirm their distinctive status. Bioclimatic analysis suggests further that A. flavipes leucogaster occupies wetter but seasonally more variable environments than its eastern relative. It is clear from the level of morphological, molecular, reproductive and distributional differences that A. flavipes flavipes and A.�flavipes leucogaster should be regarded as separate taxa for the purposes of conservation management, and their current subspecific status should be maintained.

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30

Sunnucks, Paul, e Andrea C. Taylor. "Sex of Pouch Young Related to Maternal Weight in Macropus eugenii and M. parma (Marsupialia: Macropodidae)". Australian Journal of Zoology 45, n. 6 (1997): 573. http://dx.doi.org/10.1071/zo97038.

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Competing theories of sex allocation in mammals may best be reconciled in the light of data from diverse species. The tammar wallaby (Macropus eugenii) is potentially a particularly interesting study animal because females wean only one young per year, and exhibit extreme synchronicity in the annual onset of breeding. By contrast, reproduction in the closely related parma wallaby (M. parma) is almost asynchronous. These two Australian species are found sympatrically only on Kawau Island, New Zealand, where they were introduced in about 1870. We sampled wallabies on Kawau Island in April of 1996, when both species were breeding. Although the sex ratios in both species were not significantly different from unity, offspring of M. eugenii were very significantly more likely to be male with increasing maternal weight (logistic regression χ2 = 16.8, P < 0.0001), and the fewer M. parma data showed a non-significant trend in the same direction (χ2 = 1.9, P= 0.16). These data, at least for M. eugenii, are consistent with the Trivers–Willard hypothesis, and warrant further investigation in wild and captive populations under different measured or manipulated ecological conditions. We suggest an approach utilising the characteristics of M. eugenii which might help determine whether the sex bias is determined close to conception, or is effected later in the reproductive cycle by differential survival of the sexes.

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31

Selwood, L. "Synchronization of oestrus, ovulation and birth in female Antechinus stuartii (Marsupialia: Dasyuridae)." Australian Mammalogy 8, n. 2 (1 aprile 1985): 91–96. http://dx.doi.org/10.1071/am85007.

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Abstract (sommario):

Reproduction and development were studied during six annual breeding seasons in 80 female Antechinus stuartii in laboratory colonies and in 34 females which were pregnant when trapped. Oestrus, ovulation and births were each highly synchronized within any one population from a specific locality in Victoria. Before ovulation, epithelial cells were present in the urine of the females for a mean of 20.0 clays ± 4.0 (S.D.) (N=72). Matings occurred in this period. In the colonies of animals from Kinglake, the first females came into oestrus over a 4-clay period in mid-July of 1976, 1982 and 1983. In laboratory colonies, ovulations in each year occurred over a 9 to 22-day period in the first half of August for Kinglake and Cement Creek and at later dates in August and September for animals from higher altitudes. In these colonies, half the animals or more ovulated within one week. Births were also synchronized. A similar pattern was found for field animals. Synchronization of breeding and the rate of development in A. stuartii were related to events in the life history.

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32

Geiser, Fritz. "Daily torpor and thermoregulation in antechinus (Marsupialia): influence of body mass, season, development, reproduction, and sex". Oecologia 77, n. 3 (1988): 395–99. http://dx.doi.org/10.1007/bf00378050.

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33

Smith, Meredith J. "Establishment of a captive colony of Bettongia tropica (Marsupialia: Potoroidae) by cross-fostering; and observations on reproduction". Journal of Zoology 244, n. 1 (gennaio 1998): 43–50. http://dx.doi.org/10.1111/j.1469-7998.1998.tb00005.x.

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34

Fletcher, TP. "Aspects of Reproduction in the Male Eastern Quoll, Dasyurus viverrinus (Shaw) (Marsupialia: Dasyuridae), with Notes on Polyoestry". Australian Journal of Zoology 33, n. 2 (1985): 101. http://dx.doi.org/10.1071/zo9850101.

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Abstract (sommario):

In captivity, mating activity of quolls reached a peak in late May-early June. Weights of the male accessory glands peaked about the time of mating, after which the glands regressed; in September they weighed considerably less. Weights of testes and epididymides did not vary so much, but by September spermatorrhoea had ceased and the seminiferous tubules had become aspermic. The disseminate prostate gland was divisible histologically into three segments: the anterior and posterior 2 segments had a single cell type in the tubule epithelium; but prostate 1 had two types. The three pairs of Cowper's glands had similar, simple, columnar epithelium. The seminiferous tubules, supported by numerous interstitial cells, were of diameter 360-506 �m. The mature spermatozoon was large, 232 �m long; its flagellum, oval in cross-section, was inserted midway along the wedge-shaped head at the anterior margin of a ventral groove. The gestation period varied from 20 to 24 days; if the first litter was lost early in lactation, the females might return to oestrus. The species is, therefore, polyoestrous. The oestrous cycle of one animal was 34 days.

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35

Craig, SA. "Social Organization, Reproduction and Feeding Behaviour of a Population of Yellow-Bellied Gliders, Petaurus Australis (Marsupialia: Petauridae)." Wildlife Research 12, n. 1 (1985): 1. http://dx.doi.org/10.1071/wr9850001.

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Population dynamics, habitat use and feeding behaviour in a small population of P. australis were studied in 190 ha of Tall Open Forest in the Victorian Central Highlands. Between October 1979 and December 1982, 13 marked individuals were trapped on 71 occasions during 1223 trap-nights. Gliders formed relatively stable family groups, each comprising a single resident pair living in a monogamous relationship with or without dependent offspring. They bred between August and October. Four females were observed with a single pouch young. Each pair occupied substantially separate ranges of between 30 and 55 ha. The maximum number of individuals estimated to be present during any month was eight. Den hollows were located only in living trees and one family group of three individuals used at least eight den trees within their home area. All sap-site trees were located mid-slope and were used mainly during the winter-spring months. Analysis of faeces and direct observation of feeding animals indicated that the bulk of this glider's diet is made up of arthropods, supplemented with insect and plant exudates. Some management implications, based on the life-history requirements of this glider, are discussed.

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36

Lundie-Jenkins, G. "Reproduction and growth to sexual maturity in the rufous hare-wallaby, Lagorchestes hirsutus Gould (Marsupialia: Macropodidae) in captivity." Australian Mammalogy 16, n. 1 (1993): 45. http://dx.doi.org/10.1071/am93009.

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37

Bradley, A. J. "Reproduction and life history in the red-tailed phascogale,Phascogale calura(Marsupialia: Dasyuridae): the adaptive-stress senescence hypothesis". Journal of Zoology 241, n. 4 (aprile 1997): 739–55. http://dx.doi.org/10.1111/j.1469-7998.1997.tb05745.x.

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38

Chen, Xiaolin, Chris R. Dickman e Michael B. Thompson. "Diet of the mulgara, Dasycercus cristicauda (Marsupialia : Dasyuridae), in the Simpson Desert, central Australia". Wildlife Research 25, n. 3 (1998): 233. http://dx.doi.org/10.1071/wr97087.

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Abstract (sommario):

The diet of the mulgara, Dasycercus cristicauda, from the Simpson Desert in Queensland, was analysed using scats collected between 1990 and 1995. Insects, arachnids and rodents were the main classes of prey of D. cristicauda, but reptiles, centipedes and small marsupials were also consumed. Insects represented 92% by percentage frequency of occurrence in scats, while rodents represented 33% by percentage frequency. Invertebrate prey ≥6 mm in length and vertebrate prey occurred frequently in scats, but small prey ( 1–5 mm), when present, occurred in large numbers. D. cristicauda ate more individual prey items in spring and winter than in autumn, and more large-sized prey in spring than in autumn. In autumn, D. cristicauda consumed mostly insects (100% by frequency) and few rodents (8%), but in winter and spring, switched to rodents (38% and 47% respectively) and insects (88% and 93% respectively). Seasonal shifts in diet may reflect changes in the availability of different groups of prey, or changes in prey selectivity by D. cristicauda in response to costs imposed by seasonal reproduction. The dietary flexibility of D. cristicauda may allow individuals to occupy stable ranges, and has perhaps also promoted the persistence of the species in arid areas that have been subjected to changes in land use since European settlement.

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39

Friend, GR. "Ecological Studies of a Population of Antechinus bellus (Marsupialia : Dasyuridae) in Troprical Northern Australia". Wildlife Research 12, n. 2 (1985): 151. http://dx.doi.org/10.1071/wr9850151.

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A population of the fawn antechinus, Antechinus bellus, was monitored in tropical open-forest of the Northern Territory between June 1980 and January 1983. Sixty males and 66 females were captured and marked over 9525 trap-nights. The species exhibits the typical Antechinus life-history strategy, characterized by a highly synchronized mating period after which all males die. This field evidence supports earlier speculation based on laboratory studies and limited museum collections. Mating occurs over 2 weeks in late August and parturitions about a month later. Young remain attached to the nipples for 4-5 weeks and are suckled in the nest until weaned in early January. Reproduction patterns, population dynamics and changes in relative abundance resemble those in A. stuartii from south-eastern Australia. The life-history strategy of A. bellus contrasts with that of the regionally sympatric Parantechinus bilarni, in which fecundity is lower and males may survive to breed a second time. The strategy exemplified by A. bellus does not seem optimal for the wet-dry tropics, given the erratic nature of rainfall in the early wet season, which may influence the relative abundance of the insect food resource available for lactating females and newly weaned juveniles. However the existence of patches of structurally diverse open-forest may moderate environmental fluctuations and enhance resource availability, and thus be of critical importance for the survival of local populations.

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40

Johnson, P. M. "Reproduction of the whiptail wallaby, Macropus parryi Bennett (Marsupialia : Macropodidae), in captivity with age estimation of the pouch-young". Wildlife Research 25, n. 6 (1998): 635. http://dx.doi.org/10.1071/wr97128.

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Reproduction of the whiptail wallaby, Macropus parryi, was studied in captivity. The mean length of the oestrous cycle was 41.8 days while the mean length of the gestation period was 38.0 days. M. parryi bred throughout the year and post-partum oestrus was not recorded although mating did occur during the pouch life when the pouch-young was 118–168 days of age. The length of the pouch-life was 256–267 days and weaning occurred 104–215 days after emergence from the pouch. Sexual maturity for females occurred at 509–647 days of age. An age-determination table was produced and found useful for predicting age of pouch-young using body measurements.

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41

McKenzie, LM, e DW Cooper. "Low MHC class II variability in a marsupial". Reproduction, Fertility and Development 6, n. 6 (1994): 721. http://dx.doi.org/10.1071/rd9940721.

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Abstract (sommario):

The major histocompatibility complex (MHC) loci have been shown to be highly polymorphic in most eutherian ('placental') species studied. Several hypotheses have been advanced for the maintenance of this exceptional level of genetic variation, one of which suggests that it is necessary for successful eutherian reproduction. Marsupials (metatherians) and eutherians are the only two groups of viviparous mammals, but their modes of reproduction are quite distinct. Although marsupials have placentae, they are generally shorter lived and less invasive than in eutherians. Other investigations have shown that genetic variation at marsupial MHC class I loci is probably high. Weak or non-existent mixed lymphocyte culture responses previously reported in several marsupial species have suggested a lack of class II variation. Data have therefore been collected on the level of restriction fragment length polymorphism at MHC class II beta-chain encoding loci of a marsupial, Macropus eugenii (the tammar wallaby). This level is shown to be low, between the level of MHC variation found in cheetahs and a population of lions with a restricted genetic base. Attention is drawn to the need to collect more data on the level of class II variability in both eutherians and marsupials, and to the potential of marsupials for understanding the relation, if any, between mode of reproduction and MHC variability.

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42

Cockburn, A. "Sex-Ratio Variation in Marsupials". Australian Journal of Zoology 37, n. 3 (1989): 467. http://dx.doi.org/10.1071/zo9890467.

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Abstract (sommario):

Many marsupials produce sex ratios biased towards male or female young. In several cases these changes are comfortably accommodated in the existing theory of sex allocation. Local resource competition and the Trivers-Willard hypothesis have been usefully applied to several data sets, and preliminary experimental work has supported the main tenets of theory. By contrast, several data sets lack explanation, and provide challenges to theoreticians. The high frequency of bias in marsupials does not result from data-dredging, as bias is usually reported in descriptive accounts of marsupial reproduction, without recourse to any theoretical or mechanistic explanations. It is not possible to distinguish whether the marsupial mode of reproduction is well suited to manipulate sex allocation, or whether it facilitates measurement of biased sex allocation. As for most eutherians and birds, the mechanism of prenatal sex allocation is unknown for any marsupial. However, the current interest in sex-determining mechanisms in marsupials suggests a profitable avenue for collaboration between geneticists, physiologists and evolutionary ecologists.

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43

Edwards, Melanie J., e Janine E. Deakin. "The marsupial pouch: implications for reproductive success and mammalian evolution". Australian Journal of Zoology 61, n. 1 (2013): 41. http://dx.doi.org/10.1071/zo12088.

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Abstract (sommario):

Extant mammals are divided into sub- and infraclasses that are distinguished by their mode of reproduction. The monotremes lay eggs, the marsupials give birth to altricial young that typically develop in a pouch, and the eutherians have prolonged in utero development, resulting in well developed young at birth. The three groups exhibit what appears to be a nice progression of evolution towards the well developed newborn young of eutherian mammals. However, marsupials do not represent a step in the progression of producing well developed young, but maintain a reproductive strategy that has evolved to prosper in their specific niche. The production of undeveloped young with increased development in the pouch (or counterpart) provides specific advantages to those species living in diverse environments. The evolution of this reproductive strategy provides a clever solution to the uncertain and often adverse conditions encountered by many species, and the survival of the developing young in a pouch containing potentially harmful microorganisms is truly remarkable. In this review, we explore the unique features of the pouch, highlight the research questions that remain unanswered regarding this unique marsupial attribute and discuss the advantages of the marsupial reproductive strategy and the potential role of the pouch in mammalian diversification.

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44

Tyndale-Biscoe, CH, e LA Hinds. "Influence of the immature testis on sexual differentiation in the tammar wallaby, Macropus eugenii (Macropodidae: Marsupialia)". Reproduction, Fertility and Development 1, n. 3 (1989): 243. http://dx.doi.org/10.1071/rd9890243.

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Abstract (sommario):

Reproduction in the tammar wallaby, Macropus eugenii (Desmarest), is highly seasonal in the females but not the males. This study was designed to determine whether the difference is established during early life as a result of exposure to the developing testes. At day 10 after birth, when the sex can be distinguished externally, testes were removed from males and placed under the flank skin of females, while other groups of males and females were subjected to surgery without interfering with the gonads. The testis grafts remained palpable for 3-6 months. Sex-chromosome constitution was confirmed by karyotyping. At 3 years of age, the body weights and dimensions of the grafted females were not significantly different from those of the sham-operated females, whereas those of the castrated males were significantly larger and were equal to those of the sham-operated males, indicating that there is genetical control of growth independent of the testis in this species of marsupial. During 5 years of observations, none of the grafted females ever produced young, whereas all of the sham-operated females produced young each year from the second year. The grafted females had a mixture of male and female reproductive structures. The pouch and mammary glands developed normally, as did the Mullerian duct derivatives, the vaginal complex, the uteri and the oviducts. The ovaries were either devoid of oocytes and follicles or had reduced numbers, the Wolffian ducts were retained to varying degrees, the urogenital strand had developed into a prostate indistinguishable in size and structure from that of intact males, and the genital tubercle had developed into a normal-sized penis with a crus penis and Cowper's glands. In the castrated males, the scrotum developed normally and contained the gubernaculum and vas deferens. There was no evidence of Mullerian duct derivatives, and the urogenital strand was a simple canal, as in females. There were no Cowper's glands and no penis or erectile tissue. In one hemicastrated male, there was no development of the penis, although the remaining testis occupied the scrotum and showed compensatory hypertrophy. These findings indicate that the testis, at day 10, has a profound influence on the early differentiation of the Wolffian ducts, prostate and penis but cannot influence the differentiation of the Mullerian duct derivatives. The testis does not have any effect on the development of the pouch, mammary glands or scrotum or on somatic growth, all of which are apparently under independent genetical control.

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45

Johnson, Peter M., e Steven Delean. "Reproduction in the northern bettong, Bettongia tropica Wakefield (Marsupialia: Potoroidae), in captivity, with age estimation and development of pouch young". Wildlife Research 28, n. 1 (2001): 79. http://dx.doi.org/10.1071/wr00007.

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Abstract (sommario):

Reproduction in the northern bettong, Bettongia tropica, was studied in captivity. B. tropica is capable of breeding throughout the year, and mating behaviour is similar to that reported for other Bettongia species. The length of the oestrous cycle was 21–23 days, and the period of gestation was 20–23 days. Birth was usually followed by an oestrus and mating, and a subsequent lactation-controlled embryonic diapause. The interval between loss of pouch young and birth was 19–20 days. Permanent emergence from the pouch occurred at 102–112 days, and young at foot were weaned at 166–185 days of age. Linear mixed-effects models were used to describe polynomial growth equations for age determination of pouch young using both head and pes length. The relationship between error in age prediction and each body measurement was also defined. Pes measurements provided the most accurate estimates of the age of pouch young.

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46

Johnson, Peter M., e Steven Delean. "Reproduction of Lumholtz's tree-kangaroo, Dendrolagus lumholtzi (Marsupialia : Macropodidae) in captivity, with age estimation and development of the pouch young". Wildlife Research 30, n. 5 (2003): 505. http://dx.doi.org/10.1071/wr02090.

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Abstract (sommario):

Reproduction in Lumholtz's tree kangaroo, Dendrolagus lumholtzi, was studied in captivity. The length of the oestrous cycle was 47–64 days and the gestation period was 42–48 days. Post partum oestrus and embryonic diapause were not observed in this study. The interval between loss of a pouch young and a return mating was 22 days. Pouch life was 246–275 days long and weaning occurred 87–240 days later. Sexual maturity was obtained in females as early as 2.04 years and in males at 4.6 years. Linear mixed-effects models are used to describe polynomial growth equations for age determination of pouch young using both head and pes length. The relationship between error in age prediction and each body measurement is also defined. Head and pes measurements provide equally accurate estimates of the age of pouch young.

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47

Short, Jeff, J. D. Richards e Bruce Turner. "Ecology of the western barred bandicoot (Perameles bougainville) (Marsupialia: Peramelidae) on Dorre and Bernier Islands, Western Australia". Wildlife Research 25, n. 6 (1998): 567. http://dx.doi.org/10.1071/wr97131.

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Abstract (sommario):

Population structure, reproduction, condition, movements and habitat preference were assessed for western barred bandicoots (Perameles bougainville) on Dorre and Bernier Islands over seven trapping sessions between 1988 and 1995. Data comes from 372 captures of bandicoots in 2535 trap-nights (an average of 14·7 captures per 100 trap-nights). Trap success was 5.7–25.8% on Dorre and 5.7–7.6% on Bernier. Recaptures within a trip made up 29% of bandicoot captures. The overall sex ratio (excluding recaptures) was skewed heavily towards males at 1.7: 1 for trapped animals, but varied between male and female dominance at any time according to reproductive status of females. Sex ratio of pouch young was 1.2: 1. Production of young was concentrated in the wetter winter months. The smallest western barred bandicoot with pouch young weighed 175 g. Bandicoots showed a pattern of increasing litter size with size of mother. Females with young had an average litter size of 1.8, with young reaching independence at about 100 g body weight. Large testes size relative to body size in males suggested a promiscuous mating system. Body condition could be predicted by sex (females were typically in better condition than males) and by rainfall over the previous 2 months. Some sexual dimorphism was evident, with females having longer heads and typically being heavier than males. There was no detected dimorphism between island populations. Movements of bandicoots appeared limited, with the median distance moved by animals captured more than once within a 9–11-day trapping session being 154 m. There was no significant difference in movements between the sexes, with males moving a median distance of 160 m and females 138 m within trapping sessions. The greatest movement by a male was 1020 m while the greatest distance moved by a female was 490 m. Only 13% of recorded movements were greater than 400 m. Home ranges overlapped, with 51% of traps catching more than one individual and as many as five males being caught at the same trap site. Bandicoots were widely dispersed through all habitats surveyed. Bandicoots appeared to suffer a substantial reduction in numbers on Dorre Island in a prolonged drought extending from October 1986 to April 1989, reducing overall trap success to less than 6% in the 1988 survey.

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48

Cowan, PE. "Changes in milk composition during lactation in the common brushtail possum, Trichosurus vulpecula (Marsupialia: Phalangeridae)". Reproduction, Fertility and Development 1, n. 4 (1989): 325. http://dx.doi.org/10.1071/rd9890325.

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Abstract (sommario):

The milk constituents of Trichosurus vulpecula, a folivorous marsupial, showed marked quantitative and qualitative changes during the course of lactation. The milk produced in the early stages of lactation was dilute, with about 9-13% (w/w) solids during the first 3 weeks, comprising mostly carbohydrate and protein (35-40%). At 20 weeks, about three-quarters of the way through lactation, the milk was much more concentrated, about 28% solids, with lipid the predominant fraction (30-35%), after a marked decline in carbohydrate content (20-25%). Concentrations of the electrolytes sodium and potassium also underwent marked changes. The changes in milk composition of T. vulpecula during the first three-quarters of lactation were similar to those described for a range of herbivorous, insectivorous and carnivorous marsupials. In the last quarter of lactation, however, brushtail possum milk maintained a relatively stable composition, with higher levels of carbohydrate and lower levels of lipid than for other marsupials. There appears to be a uniform pattern of changes in milk composition throughout the Marsupialia over most of lactation, with family differences evident only in the latter stages.

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49

Johnson, Peter M., e J. Steven C. Delean. "Reproduction in the Proserpine rock-wallaby, Petrogale persephone Maynes (Marsupialia : Macropodidae), in captivity, with age estimation and development of pouch young". Wildlife Research 26, n. 5 (1999): 631. http://dx.doi.org/10.1071/wr98049.

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Abstract (sommario):

Reproduction in the Proserpine rock-wallaby, Petrogale persephone, was studied in captivity. Sexual maturity, defined as age at first fertility, was attained at 20.5 months in females whereas males were not mature until 24.8 months. P. persephone is capable of breeding throughout the year. The length of the oestrous cycle was 33–38 days, while the period of gestation was 30–34 days. Birth was usually followed by an oestrus and mating, and a subsequent lactation-controlled embryonic diapause. The mean interval between loss of a pouch young and birth was 31.5 days. Pouch life was 203–215 days and young at foot were weaned 105–139 days after permanent emergence from the pouch. Linear mixed-effects models were used to describe polynomial growth equations for age determination of pouch young using both head and pes length. The relationship between error in age prediction and each body measurement was defined. Head measurements provided the most accurate estimates of the age of pouch young.

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50

Renfree, MB. "Monotreme and marsupial reproduction". Reproduction, Fertility and Development 7, n. 5 (1995): 1003. http://dx.doi.org/10.1071/rd9951003.

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Abstract (sommario):

Marsupials were regarded as curiosities by their early European discoverers, animals to be wondered at. Monotremes were even more surprising; the platypus was such an amalgam of characters that it was thought to be a hoax. They were recognized very early as mammals that could make a major contribution to our understanding of reproductive processes, and work on marsupials at the turn of the century was much in evidence. It is, however, only in the past two decades, and especially in the past few years that marsupial research has regained this position. There is no doubt that future research will strengthen this contribution, but we are faced with serious conservation questions that must be solved if we are to maintain these wonderful animals as a resource for future generations.

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