Academic literature on the topic 'Zebra finch mating behaviour'

A recent study on a captive zebra finch population suggested that variation in digit ratio (i.e. the relative length of the second to the fourth toe) might be an indicator of the action of sex steroids during embryo development, as is widely assumed for human digits. Zebra finch digit ratio was found to vary with offspring sex, laying order of eggs within a clutch, and to predict aspects of female mating behaviour. Hence, it was proposed that the measurement of digit ratio would give insights into how an individual's behaviour is shaped by its maternal environment. Studying 500 individuals of a different zebra finch population I set out to: (1) determine the proximate causes of variation in digit ratio by means of quantitative genetics and (2) to search for phenotypic and genetic correlations between digit ratio, sexual behaviour and aspects of fitness. In contrast to the earlier study, I found no sexual dimorphism in digit ratio and no effect of either laying order or experimentally altered hatching order on digit ratio. Instead, I found that variation in digit ratio was almost entirely additive genetic, with heritability estimates ranging from 71 to 84%. The rearing environment (from egg deposition to independence) explained an additional 5–6% of the variation in digit ratio, but there was no indication of any maternal effects transmitted through the egg. I found highly significant phenotypic correlations (and genetic correlations of similar size) between digit ratio and male song rate (positive correlation) as well as between digit ratio and female hopping activity in a choice chamber (negative correlation). Rather surprisingly, the strength of these correlations differed significantly between subsequent generations of the same population, illustrating how quickly such correlations can appear and disappear probably due to genotype–environment interactions.

In socially monogamous species, low availability of sexually active unpaired individuals in the local population may constrain mate choice, resulting in mating with sub-optimal partners. Here we experimentally investigate whether female reproductive behaviour is different when paired with a preferred or a non-preferred male in the zebra finch (Taeniopygia guttata). First, we assessed female mating preferences using a four-way choice apparatus, then females were caged together with either their preferred or least-preferred male. Female reproductive motivation, assessed by the propensity of laying eggs within two weeks from pairing and clutch mass, did not differ between the two experimental groups. Females responded to mate removal by either increasing their care, so as to compensate for the lost care of their mate, or by significantly reducing incubation. This bimodal response was not explained by mate preference, nevertheless, we found that females with lower baseline (i.e., pre-manipulation) incubation effort were more likely to cease incubation during mate removal. Taken together, we found no evidence that female reproductive behaviour varies along with mate preference.

Birds choose mates on the basis of colour, song and body size, but little is known about the mechanisms underlying these mating decisions. Reports that zebra finches prefer to view mates with the right eye during courtship, and that immediate early gene expression associated with courtship behaviour is lateralized in their left hemisphere suggest that visual mate choice itself may be lateralized. To test this hypothesis, we used the Gouldian finch, a polymorphic species in which individuals exhibit strong, adaptive visual preferences for mates of their own head colour. Black males were tested in a mate-choice apparatus under three eye conditions: left-monocular, right-monocular and binocular. We found that black male preference for black females is so strongly lateralized in the right-eye/left-hemisphere system that if the right eye is unavailable, males are unable to respond preferentially, not only to males and females of the same morph, but also to the strikingly dissimilar female morphs. Courtship singing is consistent with these lateralized mate preferences; more black males sing to black females when using their right eye than when using their left. Beauty, therefore, is in the right eye of the beholder for these songbirds, providing, to our knowledge, the first demonstration of visual mate choice lateralization.

Quality differences between offspring sired by the social and by an extra-pair partner are usually assumed to have a genetic basis, reflecting genetic benefits of female extra-pair mate choice. In the zebra finch ( Taeniopygia guttata ), we identified a colour ornament that is under sexual selection and appears to have a heritable basis. Hence, by engaging in extra-pair copulations with highly ornamented males, females could, in theory, obtain genes for increased offspring attractiveness. Indeed, sons sired by extra-pair partners had larger ornaments, seemingly supporting the genetic benefit hypothesis. Yet, when comparing ornament size of the social and extra-pair partners, there was no difference. Hence, the observed differences most likely had an environmental basis, mediated, for example, via differential maternal investment of resources into the eggs fertilized by extra-pair and social partners. Such maternal effects may (at least partly) be mediated by egg size, which we found to be associated with mean ornament expression in sons. Our results are consistent with the idea that maternal effects can shape sexual selection by altering the genotype–phenotype relationship for ornamentation. They also caution against automatically attributing greater offspring attractiveness or viability to an extra-pair mate's superior genetic quality, as without controlling for differential maternal investment we may significantly overestimate the role of genetic benefits in the evolution of extra-pair mating behaviour.

Birdsong is a classic example of a learned social behaviour. Song behaviour is also influenced by genetic factors, and understanding the relative contributions of genetic and environmental influences remains a major goal. In this study, we take advantage of captive zebra finch populations to examine variation in a population-level song trait: song variability. Song variability is of particular interest in the context of individual recognition and in terms of the neuro-developmental mechanisms that generate song novelty. We find that the Australian zebra finch Taeniopygia guttata castanotis ( TGC ) maintains higher song diversity than the Timor zebra finch T. g. guttata ( TGG ) even after experimentally controlling for early life song exposure, suggesting a genetic basis to this trait. Although wild-derived TGC were intermediate in song variability between domesticated TGC populations and TGG , the difference between domesticated and wild TGC was not statistically significant. The observed variation in song behaviour among zebra finch populations represents a largely untapped opportunity for exploring the mechanisms of social behaviour.

Songbirds are important models for the study of social behaviour and communication. To complement the recent genome sequencing of the domesticated zebra finch, we sequenced the brain transcriptome of a closely related songbird species, the violet-eared waxbill ( Uraeginthus granatina ) . Both the zebra finch and violet-eared waxbill are members of the family Estrildidae, but differ markedly in their social behaviour. Using Roche 454 RNA sequencing, we generated an assembly and annotation of 11 084 waxbill orthologues of 17 475 zebra finch genes (64%), with an average transcript length of 1555 bp. We also identified 5985 single nucleotide polymorphisms (SNPs) of potential utility for future population genomic studies. Comparing the two species, we found evidence for rapid protein evolution ( ω ) and low polymorphism of the avian Z sex chromosome, consistent with prior studies of more divergent avian species. An intriguing outlier was putative chromosome 4A, which showed a high density of SNPs and low evolutionary rate relative to other chromosomes. Genome-wide ω was identical in zebra finch and violet-eared waxbill lineages, suggesting a similar demographic history with efficient purifying natural selection. Further comparisons of these and other estrildid finches may provide insights into the evolutionary neurogenomics of social behaviour.

AbstractThis paper examined the relative importance of visual and vocal cues for song tutor choice. In the first study zebra finches, Taeniopygia guttata, and Bengalese finches, Lonchura striata, were housed with two song tutors at independence, a zebra finch singing Bengalese finch song and a Bengalese finch singing zebra finch song. All the males tended to learn from the conspecific song tutor, irrespective of whether they had been raised by a pair of conspecifics, the female alone or cross-fostered to a pair of the other species. In the second study zebra finches were housed at independence with two conspecific song tutors, one with a normal song and one which sang Bengalese finch song elements. There was no tendency to learn zebra finch elements which suggests that species-specific elements are not important for song tutor choice in zebra finches. Other vocal differences between the tutors such as length of the song phrase and species-specific call notes might bias learning in favour of the conspecific. Visual differences between the two species, both in appearance and behaviour, seem to be important. Parental cues before independence appear to be relatively uninfluential. However, siblings may be important, both the species and number per clutch: this is a factor which has been overlooked in previous studies of song learning.

ct: I orally exposed zebra finch, Taeniopygia guttata, to 4.7 or 720 mug estradiol/g diet for eight days to test the hypothesis that estrogens can affect their behaviour. In a two choice preference test, low estradiol males spent (P = 0.01) more time near other males after six days of treatment and their courtship also diminished. Singing scores decreased (P = 0.01) in both treated groups, dancing score (P = 0.01) in the high estradiol and mounting in the low estradiol males were lower (P = 0.02) compared to controls on day 4 of the treatment period. Pecks and chases targeting males were lower in both treatment groups. More high estradiol females performed tail quivering on day 4 (P < 0.01) and their score for this behaviour was also significantly higher (P < 0.01). These females also accepted mounts by the stimulus male more often.

Due to mounting evidence that the early environment experienced by a juvenile can affect the morphology and physiology of the adult, there is currently great interest in how environmental variability may shape the behavioural phenotype, and whether such shaping has adaptive benefits. It is clear for example that the developmental environment will have immediate effects on an animal in terms of its survival and performance. Individuals with access to little food or exposed to high levels of predation will have lower survival, and resource-poor surroundings may mean that a young individual is unable to forage successfully, or disperse as normal. However, there is now increasing evidence to suggest that early environmental conditions are also important in determining the success of the adult, meaning that experiences during early development can have significant long-term effects. In this thesis, I consider the effects of diet quality and exposure to stress in postnatal life on behavioural traits in adulthood, using the zebra finch (Taeniopygia guttata) as a model species. There is already evidence to suggest that the early environment can shape behaviour, and consequently, many aspects of behaviour may have important developmental origins that are not a direct result of the genotype. Two populations of birds were used throughout this collection of studies. The first was raised under different diet regimes, in which both diet quality and consistency were manipulated during the first weeks of life. The second did not undergo any diet manipulation, but were given oral doses of the stress hormone corticosterone or a peanut oil control in the nestling phase. Both populations then underwent a variety of behavioural tests to determine the effects of their early life experiences. In examining the behaviour of zebra finches, I found that these birds displayed distinct and repeatable behavioural traits, and discuss the idea that they may even exhibit behavioural syndromes, since I was able to show strong correlations between various responses. I studied the effect of both exposure to varying diet quality and consistency in early life on various behavioural traits in adulthood, and found evidence to suggest that certain behavioural responses are linked to the consistency of the nutritional environment experienced by the chick. When tested in adulthood, birds that had experienced a consistent early environment (regardless of food quality) showed a strong trend towards being bolder than birds raised on a variable diet, and this result was replicated in a subset of the original population over a year later, suggesting real longitudinal effects. Such an outcome may suggest that certain behavioural traits are developed in response to environmental sampling, so as to maximise fitness in the anticipated environment. Similarly, I investigated the behaviour of birds exposed to corticosterone in early life, but found no evidence to suggest that their behavioural traits had been directly shaped by exposure to this hormone. Interestingly however, relative growth rate was linked to individual boldness, a finding which could again possibly be explained through adaptive environmental shaping, in which growth rate is used as a proxy for environmental richness. Using subsets of the populations of birds that were examined for personality traits, I also considered the effects of the early environment on adult performance in two simple memory tests; specifically studying the ability of birds to search for and remember the location of a food item using environmental cues. In both the diet and hormone manipulated groups, I was able to show that those individuals that had experienced a sub-optimal early environment were compromised in their performance on these simple learning and memory tasks. Again, these were long term effects, since the tests were carried out many months after the birds became adult, suggesting they could not be compensated for, and consequently, since spatial and visual memory are important throughout life, could not be said to be adaptive under any circumstances. Finally, I also looked for effects of the diet and hormone treatments on the ability of the birds to become dominant. In tests using the birds raised on the different diet regimes, results again suggested that diet consistency was important, as birds raised on a consistent diet were generally more aggressive than those raised on a variable diet, and also showed a trend towards winning more of their individual interactions. Consequently, in this study, nutritional stability made individuals generally more successful in conspecific interactions and thus more likely to hold a higher dominance position, though this is complicated by the fact that dominance was not linked to priority of access to other desirable resources such as potential mates. Using the same experimental design on the birds raised under the hormone treatment, there were trends to suggest that exposure to corticosterone could have negative effects on dominance-related behaviour under certain environmental conditions, but sample sizes were too small to allow firm conclusions. Overall, this study provides strong evidence for the idea that behaviour can be modified by the environmental conditions an individual experiences in early life. Since behavioural traits will impinge significantly on individual fitness, such effects are of general interest. Since there are also studies that suggest that environmental shaping can be adaptive, I discuss the costs and benefits involved in the different behavioural phenotypes that arise as a result of environmental variation.

A surge of recent work elucidating a role for learning and memory in avian nest-building behaviour has challenged the long-standing assumption that nest building develops under genetic control. Whereas that work has been addressed at describing the cognitive mechanisms underpinning nest-building behaviour, almost nothing is known about either the neurobiological processes controlling nest building or the selection pressures responsible for the diversity in avian nest-building behaviour. Here, I sought to identify both the neural substrates involved in nest-building behaviour and some of those selection pressures. First, I used expression of the immediate early gene product Fos, an indirect marker of neuronal activity, to identify brain regions activated during nest-building behaviour in the brains of nest-building and control zebra finches (Taeniogypia guttata). I found that neural circuits involved in motor control, social behaviour, and reward were activated during nest building. Furthermore, I found that subpopulations of neurons that signal using the nonapeptides vasotocin and mesotocin and the neurotransmitter dopamine located within some of these neural circuits were also activated during nest building, suggesting these cell-signalling molecules may be involved in controlling nest-building behaviour. Next, I found that variation in the amount of folding in the cerebellum, a brain structure thought to be involved in manipulative skills, increased with increasing nest structural complexity, suggesting that the cerebellum is also involved in nest building. Finally, using evolutionary statistical models, I found support for the hypothesis that nest-site competition off-ground and increased predation pressure on the ground in Old World babblers (Timaliidae) led to the co-evolution of building domed nests on the ground. Here, then, I provide the first evidence of potential neural substrates controlling and selection pressures contributing to variation in nest-building behaviour.

S’approvisionner en nourriture est essentiel à la survie et au succès reproducteur. Lorsque les animaux font face à des changements environnementaux brutaux, ils doivent s’ajuster rapidement à leur nouvel environnement et parfois même innover dans leur façon de s’approvisionner. Des processus comportementaux et cognitifs, tels que l’innovation et l’apprentissage, permettent aux animaux d'intégrer de nouveaux comportements à leur répertoire comportemental afin de s'adapter de façon optimale. Les performances cognitives varient entre les individus d’une même population et bien que des études récentes se soient intéressées aux causes de ce phénomène, de convaincantes évidences sont manquantes afin d’expliquer pourquoi ces variations sont maintenues. Au cours de ce mémoire, les questions des pressions de sélection s'exerçant sur les performances d’alimentation par une tâche motrice nouvelle sont abordées afin de mieux comprendre l'évolution des capacités cognitives au sein d'une population captive de diamants mandarins (Taeniopygia guttata). Nous avons tout d'abord testé si les femelles diamants mandarins modifient leurs préférences d'accouplement après avoir observé la performance d'alimentation par une tâche motrice nouvelle des mâles. Afin de déterminer si les femelles sont capables de discriminer entre les mâles sur la base de leur capacité cognitive, nous avons également évalué les performances d’apprentissage de chacune d’elles. En effet, des études ont suggéré qu’il peut être coûteux, spécialement en terme de temps, de discriminer entre des partenaires potentiels sur cette base. La généralisation d’une préférence pour un mâle performant à d’autres mâles possédant le même phénotype permettrait la réduction de ces coûts. Nous avons donc finalement testé si les femelles diamants mandarins peuvent généraliser leur préférence après avoir observé les performances d’alimentation pour une tâche motrice nouvelle d’un mâle. Nos résultats suggèrent que les femelles diamants mandarins ne peuvent évaluer les capacités cognitives d’un mâle par l’intermédiaire de traits indicateurs. Toutefois, nous avons démontré qu’une observation directe des performances d’alimentation d’un mâle guide le choix d’appariement des femelles. Également, nous avons montré que les femelles peuvent généraliser l’apparence du mâle le plus performant et utiliser cette information lors de l’évaluation de nouveaux mâles. La relation entre les performances cognitives et le choix de partenaire pourraient s’expliquer par exemple par une meilleure exploitation de l’habitat, mais nécessite des études plus approfondies.
Successful foraging is essential for survival and reproductive success. When animals face rapidly change due to climate change or anthropogenic habitat destruction, they are force to quickly adjust their behaviour such as foraging. Innovation and learning, two processes related to cognitive functions, are know to allow animals to incorporate novel behaviours into their behavioural repertoires and thus to facilitate optimal responses to environmental change. Cognitive performance vary between and within individuals and although several studies have rencently addressed the causes, convicing evidences for why inter-individual variations in cognitive performance are maintained in a population are still lacking. During my Masters, I investigated different selective pressures acting on foraging performance on a novel motor task to better understand the evolution of cognitive abilities in a captive population of zebra finch (Taeniopygia guttata). Firstly, we investigated whether female zebra finches modify their mating preferences after having observed the foraging performance of males on a novel motor task. We also assessed each bird’s learning performance in a color associative task in order to check whether females could discriminate between the two males based on their learning performance. Discriminating among mates based on their cognitive ability might be very costly for females, especially in terms of time. Therefore, one way to reduce the cost of assessing mate would be to generalize their preferences to any male with the same phenotype as the most efficient observed individual. We finaly investigated whether female zebra finches can generalize their mating preferences after having observed a male’s foraging performance on a novel motor task. Our findings suggest that female zebra finches would be unable to assess male cognitive ability indirectly via morphological traits. However our results demonstrate that direct observation of the males’ performance on a foraging task can guide female mating preferences. We also demonstrates that female zebra finches can generalize the appearance of the male that is the most efficient at solving a motor task and then use this information to assessing new males. The relationship between cognitive performance and mating preference might be mediated throught habitat exploitation for example, but requires further investigation.