Post doc Research
My second post doc research focuses on the spill over effects of learning the color of aposematic preys on mate choice preferences in cannibalistic female jumping spiders.
Habronattus pyrrithrix courtship display. Photo: Daniel Zurek
My first post doc research focuses on the consequences of behavioural compatibility on fitness and divorce in a wild population of bird.
For many decades research on mate choice has focused on preferences for quality indicators, yet in some species mating preferences are largely idiosyncratic (with little consensus about attractiveness), suggesting that such preferences might target at genetic or behavioral compatibility. In a previous study I conducted on a socially monogamous species (the zebra finch – see below), I found, by the mean of cross-fostering, that the specific combination of the rearing parents was what determined offspring survival, and that pairs that were allowed free choice obtain higher fitness. I now study this parental phenotypic interaction, or behavioural compatibility, in more details, by looking at the provisioning behaviour of house sparrows from a wild island population monitored for 15 years. More precisely, I am testing whether behavioural compatibility, in terms of coordination, i.e. synchrony and alternation, in parental care, affects the fitness of pairs. In addition, I am analysing whether birds directly assess partner behaviour as their criterion for divorcing, or whether they respond to outcomes in term of reproductive success.
My PhD research focuses on the benefits of mate choice and extra-pair behaviour in the zebra finch.
My aim is to experimentally test some of the fundamental hypotheses of the sexual selection theory. To do this, I conduct experiments on a captive population of recently wild derived zebra finches (Taeniopygia guttata).
Mate choice can bring direct or indirect fitness benefits which may either arise from the overall quality of the chosen partner or from the compatibility between partners. The zebra finch is a life‐long monogamous species that breeds opportunistically in Australia, exhibits bi‐parental care and shows surprisingly high rates of embryo mortality and low rates of extra-pair paternity. Moreover, females show strong preferences but little consensus regarding what constitutes male attractiveness. In such a species, mate choice is expected to be crucial and could target both absolute quality and relative compatibility.
Females could choose a social or an extra-pair partner based on
1) Surely, the most fundamental assumption of the sexual selection theory is that individuals involved in a mate choice process aim to obtain a partner of the best possible quality, for instance to gain better paternal care and/or better genes for their offspring. Nevertheless, there is little consensus on what constitutes a quality indicator. Inbred birds, compared to outbred birds, show a much lower fitness and have altered phenotypic traits. Therefore, they appear to be of low genetic quality. Under mutual mate choice we expect assortative pairing for quality (inbreeding status) or, if only one sex is choosy, we expected the low quality individuals of the other sex to become paired last. In several free choice experiments conducted both on our domesticated population of zebra finches and our recently wild derived one, we analyzed pair formation and 70% of all courtships happening in communal breeding aviaries. A parallel experiment involved forced pairs breeding in aviaries (bonds were formed by setting up pairs in cages for several months) in order to see if females paired to a low quality male would engage more in extra-pair copulations. Another experiment tested in a two-way choice chamber apparatus the repeatability of female preferences for beak colour, trait strongly condition dependent and therefore affected by inbreeding depression.
We have now accumulated extensive (lack of) evidence, thanks to the help of our masters’ students, we will hopefully soon present to what extent female zebra finches discriminate against low quality males. Results might be really surprising !
2) Mating between close relatives nearly always leads to inbreeding depression, which should promote the evolution of inbreeding avoidance mechanisms, especially in sexually monogamous species. The zebra finch has been shown to suffer strongly from inbreeding depression, and this species has been used repeatedly in studies of inbreeding avoidance. However, no conclusive evidence for such avoidance has emerged. We summarized the previous research in a small meta-analysis showing that zebra finches appear to mate randomly with regard to relatedness (odds ratio for full-sibling mating = 0.96). Nevertheless, we notice that kin recognition by direct familiarization might have been prevented in all the previous studies because siblings had always been experimentally separated before puberty and only reunited during adulthood. Recognizing individuals across different life stages may be cognitively demanding; therefore, in this species, it may require that siblings stay in contact throughout development. We conducted an experiment where birds were given the choice between a full sibling that stayed with them without interruption from hatching until adulthood and an unrelated bird familiar from independence (35 days of age) to adulthood. In contrast to all earlier studies, we found a significant avoidance of inbreeding (odds ratio = 0.50). Although other mechanisms cannot be excluded, we suggest that zebra finches avoid inbreeding only if birds can keep track of their kin. Implications for the design of follow-up studies should be considered. Behavioral Ecology.
3) In socially monogamous species, the reasons for female infidelity are still controversial. A popular hypothesis is that females could seek extra-pair copulations as an insurance against hatching failure caused by male infertility or incompatibility. In species where couples breed repeatedly, females could use previous hatching success as a cue to assess their partner’s infertility (or incompatibility). Hence, it has been predicted that females should increase their infidelity after experiencing hatching failures, but this hypothesis has never been tested experimentally. We manipulated hatching success of pairs of zebra finches and measured female willingness to engage in extra-pair copulations. By experimentally cross-fostering fertile and infertile eggs, couples either experienced 100% or cica 35% hatching success in each of three consecutive clutches. Contrary to our prediction, females that experienced repeated hatching failure did not increase their responsiveness toward extra-pair males relative to those females with 100% hatching success. Moreover, there was no difference in female calling rate for the partner after male removal and no occurrence of divorce when the opportunity was given. These findings seem to contradict the common view that reproductive failure weakens the pair bond. Furthermore, a critical review of the literature suggests that there is no convincing evidence supporting this hypothesis in other species either. We highlight that this fundamental area of behavioural ecology research is still much in need of specific experimental work that controls for confounding factors. Behavioral Ecology.
4) In some species like the zebra finch, mating preferences are largely idiosyncratic (with little consensus about attractiveness), suggesting that such preferences might target genetic or behavioural compatibility. Very few studies have attempted to quantify the fitness consequences of allowing versus preventing such idiosyncratic mate choice. In our populations of zebra finches, when freshly laid eggs are individually cross-fostered for incubation and rearing, embryo mortality (before hatching) primarily depends on the identity of the genetic parents, while offspring mortality during the chick-rearing period depends on foster-parent identity. Therefore, when mate choice is prevented, we expect to see an increase in embryo mortality if mate choice targets genetic compatibility (for embryo viability), and an increase in chick mortality if mate choice is aiming at behavioural compatibility (for better chick rearing). In communal breeding aviaries, we monitored the fitness and behaviour of zebra finches in experimental pairings resulting from either free mate choice or forced pairings, using a design where variation in overall partner quality is not a confounding factor. Contrary to the compatible genes hypothesis, pairs from both treatments showed equal rates of embryo mortality. Yet, in line with the behavioural compatibility hypothesis, chosen pairs were better at raising chicks and overall achieved a 37% higher fitness. Further exploratory analyses reveal several interesting differences in behaviour and fitness components between such ‘love’ versus ‘arranged marriages’. Poster Ecology & Behaviour 2014 Montpellier