Biology subjects

Kempenaers, B.

Publications and source records attributed to Kempenaers, B..

25 records · Page 2Linked to original sources

bioRxiv2019

Timing of arrival in the breeding area is repeatable and affects reproductive success in a non-migratory population of blue tits

O_LIEvents in one part of the annual cycle often affect the performance (and subsequently fitness) of individuals later in the season (carry-over effects). An important aspect of this relates to the timing of activities. For example, many studies on migratory birds have shown that relatively late spring arrival in the breeding area reduces both the likelihood of getting a mate or territory and reproductive success.\nC_LIO_LIIn contrast, relatively little is known about movements of individuals in non-migratory populations during the non-breeding season. Few studies have investigated the timing of arrival at the breeding area in such species, possibly due to the assumption that most individuals remain in the area during the non-breeding season.\nC_LIO_LIIn this study, we used four years of data from a transponder-based automated recording system set up in a non-migratory population of blue tits (Cyanistes caeruleus) to describe individual variation in arrival at the breeding site. We investigated whether this variation can be explained by individual characteristics (sex, body size, or status), and we assessed its effect on aspects of reproductive success in the subsequent breeding season.\nC_LIO_LIWe found substantial variation in arrival date and demonstrate that this trait is individual-specific (repeatable). Females arrived later than males, but the arrival dates of social pair members were more similar than expected by chance. Arrival predicted both whether an individual would end up breeding that season, and several aspects of its breeding success.\nC_LIO_LIOur study suggests that non-migratory species show a form of incipient migration behaviour in that they leave the breeding area during the non-breeding season. We conclude that the timing of pre-breeding events, in particular arrival date, may be an overlooked, but important, fitness-relevant trait in non-migratory species.\nC_LI

animal behavior and cognition↗

bioRxiv2019

The role of genetic constraints and social environment in explaining female extra-pair mating

Why females of socially monogamous species copulate with males other than their partner has been a long-standing, unresolved puzzle. We previously reported that female promiscuity appears to be a genetic corollary of male promiscuity (intersexual pleiotropy hypothesis). Here we put this earlier finding to a critical test using the same population of zebra finches Taeniopygia guttata. After three generations of artificial selection on male courtship rate, a correlate of extra-pair mating, we assess whether female promiscuity changed by indirect selection and we re-examine the crucial genetic correlations. Our new analyses with substantially increased statistical power clearly reject the hypothesis that male and female promiscuity are genetically homologous traits. Our study highlights that individual females show low repeatability in extra-pair mating behavior across different social environments. This emphasizes the potential importance of pair bond strength and the availability of favored extra-pair males as factors explaining variation in patterns of female promiscuity.

evolutionary biology↗

bioRxiv2019

The great tit HapMap project: a continental-scale analysis of genomic variation in a songbird

A major aim of evolutionary biology is to understand why patterns of genomic diversity vary among populations and species. Large-scale genomic studies of widespread species are useful for studying how the environment and demographic history shape patterns of genomic divergence, and with the continually decreasing cost of sequencing and genotyping, such studies are now becoming feasible. Here, we carry out one of the most geographically comprehensive surveys of genomic variation in a wild vertebrate to date; the great tit (Parus major) HapMap project. We screened ca 500,000 SNP markers across 647 individuals from 29 populations, spanning almost the entire geographic range of the European great tit subspecies. We found that genome-wide variation was consistent with a recent colonisation across Europe from a single refugium in South-East Europe, with bottlenecks and reduced genetic diversity in island populations. Differentiation across the genome was highly heterogeneous, with clear "islands of differentiation" even among populations with very low levels of genome-wide differentiation. Low local recombination rate in the genome was a strong predictor of high local genomic differentiation (FST), especially in island and peripheral mainland populations, suggesting that the interplay between genetic drift and recombination is a key driver of highly heterogeneous differentiation landscapes. We also detected genomic outlier regions that were confined to one or more peripheral great tit populations, most likely as a result of recent directional selection at the range edges of this species. Haplotype-based measures of selection were also related to recombination rate, albeit less strongly, and highlighted population-specific sweeps that likely resulted from positive selection. These regions under positive selection contained candidate genes associated with morphology, thermal adaptation and colouration, providing promising avenues for future investigation. Our study highlights how comprehensive screens of genomic variation in wild organisms can provide unique insights into evolution.

evolutionary biology↗

bioRxiv2018

RECONCILING ECOGEOGRAPHICAL RULES: RAINFALL AND TEMPERATURE PREDICT GLOBAL COLOUR VARIATION IN THE LARGEST BIRD RADIATION

Ecogeographical rules that associate climate with organismal form and function can reveal patterns of climatic adaptation. Two rules link animal coloration with climate: Glogers rule (darker coloration where wet and warm), and Bogerts rule (darker coloration where cold). Whereas Glogers rule was proposed for endotherms, and Bogerts rule for ectotherms, both rules may apply more broadly, despite their seemingly opposing effects. Here we test this contradiction on a global scale across passerine birds. Consistent with Glogers rule, birds were darker in wetter areas and, following Bogerts rule, lighter where warm, although birds became lighter again at very low temperatures. Rainfall and temperature had antagonistic or additive effects depending on their pattern of covariation, and this predicted whether birds followed the rules. We integrate both rules into a general framework to explain heterogeneity in climatic effects on coloration, which has implications to understand patterns of diversification, climatic adaptation and climate change impacts.

evolutionary biology↗

bioRxiv2018

Meta-analysis challenges a textbook example of status signalling: evidence for publication bias

The status signalling hypothesis aims to explain conspecific variation in ornamentation by suggesting that some ornaments signal dominance status. Here, we use multilevel meta-analytic models to challenge the textbook example of this hypothesis, the black bib of house sparrows (Passer domesticus). We conducted a systematic review, and obtained raw data from published and unpublished studies to test whether dominance rank is positively associated with bib size across studies. Contrary to previous studies, our meta-analysis did not support this prediction. Furthermore, we found several biases in the literature that further question the support available for the status signalling hypothesis. First, the overall effect size of unpublished studies was zero, compared to the medium effect size detected in published studies. Second, the effect sizes of published studies decreased over time, and recently published effects were, on average, no longer distinguishable from zero. We discuss several explanations including pleiotropic, population- and context-dependent effects. Our findings call for reconsidering this established textbook example in evolutionary and behavioural ecology, raise important concerns about the validity of the current scientific publishing culture, and should stimulate renewed interest in understanding within-species variation in ornamental traits.

evolutionary biology↗

bioRxiv2017

Temporary mate removal during incubation leads to variable compensation in a biparental shorebir

Biparental care for offspring requires cooperation, but it is also a potential source of conflict, since one parent may care less at the expense of the other. How, then, do parents respond to the reduction of their partners care? Theoretical models predict that parents that feed offspring should partially compensate for the reduced care of their partner. However, for incubating birds partial compensation is unlikely the optimal strategy, because the entire brood can fail with reduced care. Although biparental incubation dominates in non-passerine birds, short-term manipulations of parental care and evaluations of individual differences in the response, both crucial to our understanding of parental cooperation, are scarce. Here, we describe the response of semipalmated sandpiper (Calidris pusilla) parents to a 24-hour removal of their partner during the incubation period, explore factors that can explain individual variation in the response, and describe how incubation rhythms changed after the removed parent returned. On average, the parents compensated partially for the absence of their partners care (59%; 95%CI: 49-70%, N = 25 individuals). The level of compensation did not differ between the sexes. However, individual responses varied from no to full compensation (2-101%). In seven nests where the removed parent never returned, the widowed parent attended the nest for 0-10 days (median: 4 days). In contrast to patterns observed in undisturbed nests or in uniparental species, nest attendance during compensation tended to be higher during the warmer part of the day. Although the level of compensation was not related to the before-experimental share of incubation, more responsive parents (that left the nest earlier upon human approach) compensated more. The quality of incubation in the after-experimental period was lower than usual, but improved quickly over time. Our findings suggest that full compensation might be limited by energetic constraints or by variation in responsiveness to the absence of the partner. Nevertheless, semipalmated sandpiper parents are able to adjust their subsequent incubation behaviour to take full responsibility for the nest when widowed. Because (nearly) full compensation was the most common response, we speculate that all individuals attempt full compensation, but that some fail because their energy stores get depleted, or because they are less responsive to the absence of their partner.

animal behavior and cognition↗

bioRxiv2017

Flexible Parental Care: Uniparental Incubation In Biparentally Incubating Shorebirds

Recent findings suggest that relative investment of females and males into parental care depends on the populations adult sex-ratio. For example, all else being equal, males should be the more caring sex if the sex ratio is male biased. Whether such outcomes are evolutionary fixed (i.e. related to the species typical sex-ratio) or whether they arise through flexible responses of individuals to the current population sex-ratio remains unclear. Nevertheless, a flexible response might be limited by evolutionary history when one sex loses the ability to care or when a single parent cannot successfully care. Here, we demonstrate that after the disappearance of one parent, individuals from 8 out of 15 biparentally incubating shorebird species were able to incubate uniparentally for 1-19 days (median = 3, N = 69). Such uniparental phases often resembled the incubation rhythm of species with obligatory uniparental incubation. Although it has been suggested that females of some shorebirds desert their brood after hatching, our findings indicate that either sex may desert prior to hatching. Strikingly, in 27% of uniparentally incubated clutches - from 5 species - we document successful hatching. Our data thus reveal the potential for a flexible switch from biparental to uniparental care.

evolutionary biology↗