High fidelity: extra-pair fertilisations in eight Charadrius plover species are not associated with parental relatedness or social mating system

Extra-pair paternity is a common reproductive strategy in many bird species. However, it remains unclear why extra-pair paternity occurs and why it varies among species and populations. Plovers (Charadrius spp.) exhibit considerable variation in reproductive behaviour and ecology, making them excellent models to investigate the evolution of social and genetic mating systems. We investigated inter- and intra-specific patterns of extra-pair parentage and evaluated three major hypotheses explaining extra-pair paternity using a comparative approach based on the microsatellite genotypes of 2049 individuals from 510 plover families sampled from twelve populations that constituted eight species. Extra-pair paternity rates were very low (0 to 4.1% of chicks per population). No evidence was found in support of the sexual conflict or genetic compatibility hypotheses, and there was no seasonal pattern of extra-pair paternity (EPP). The low prevalence of EPP is consistent with a number of alternative hypotheses, including the parental investment hypothesis, which suggests that high contribution to care by males restricts female plovers from engaging in extra-pair copulations. Further studies are needed to critically test the importance of this hypothesis for mate choice in plovers

RAD sequencing sheds new light on the genetic structure and local adaptation of European scallops and resolves their demographic histories.

Recent developments in genomics are advancing our understanding of the processes shaping population structure in wild organisms. In particular, reduced representation sequencing has facilitated the generation of dense genetic marker datasets that provide greater power for resolving population structure, investigating the role of selection and reconstructing demographic histories. We therefore used RAD sequencing to study the great scallop Pecten maximus and its sister species P. jacobeus along a latitudinal cline in Europe. Analysis of 219 samples genotyped at 82,439 single nucleotide polymorphisms clearly resolved an Atlantic and a Norwegian group within P. maximus as well as P. jacobeus, in support of previous studies. Fine-scale structure was also detected, including pronounced differences involving Mulroy Bay in Ireland, where scallops are commercially cultured. Furthermore, we identified a suite of 279 environmentally associated loci that resolved a contrasting phylogenetic pattern to the remaining neutral loci, consistent with ecologically mediated divergence. Finally, demographic inference provided support for the two P. maximus groups having diverged during the last glacial maximum and subsequently expanded, whereas P. jacobeus diverged around 95,000 generations ago and experienced less pronounced expansion. Our results provide an integrative perspective on the factors shaping genome-wide differentiation in a commercially important marine invertebrate

Extremely low Plasmodium prevalence in wild plovers and coursers from Cape Verde and Madagascar

Martínez-de la Puente J, Eberhart-Phillips L, Cristina Carmona-Isunza M, et al. Extremely low Plasmodium prevalence in wild plovers and coursers from Cape Verde and Madagascar. Malaria Journal. 2017;16(1): 243

Chemical fingerprints encode mother-offspring similarity, colony membership, relatedness and genetic quality in fur seals

Chemical communication underpins virtually all aspects of vertebrate social life, yet remains poorly understood because of its highly complex mechanistic basis. We therefore used chemical fingerprinting of skin swabs and genetic analysis to explore the chemical cues that may underlie mother–offspring recognition in colonially breeding Antarctic fur seals. By sampling mother–offspring pairs from two different colonies, using a variety of statistical approaches and genotyping a large panel of microsatellite loci, we show that colony membership, mother–offspring similarity, heterozygosity, and genetic relatedness are all chemically encoded. Moreover, chemical similarity between mothers and offspring reflects a combination of genetic and environmental influences, the former partly encoded by substances resembling known pheromones. Our findings reveal the diversity of information contained within chemical fingerprints and have implications for understanding mother–offspring communication, kin recognition, and mate choice

Sex-specific early survival drives adult sex ratio bias in snowy plovers and impacts mating system and population growth

Eberhart-Phillips L, Küpper C, Miller TEX, et al. Sex-specific early survival drives adult sex ratio bias in snowy plovers and impacts mating system and population growth. Proceedings of the National Academy of Sciences of the United States of America. 2017;114(27):E5474-E5481.Adult sex ratio (ASR) is a central concept in population biology and a key factor in sexual selection, but why do most demographic models ignore sex biases? Vital rates often vary between the sexes and across life history, but their relative contributions to ASR variation remain poorly understood—an essential step to evaluate sex ratio theories in the wild and inform conservation. Here, we combine structured two-sex population models with individual-based mark–recapture data from an intensively monitored polygamous population of snowy plovers. We show that a strongly male-biased ASR (0.63) is primarily driven by sex-specific survival of juveniles rather than adults or dependent offspring. This finding provides empirical support for theories of unbiased sex allocation when sex differences in survival arise after the period of parental investment. Importantly, a conventional model ignoring sex biases significantly overestimated population viability. We suggest that sex-specific population models are essential to understand the population dynamics of sexual organisms: reproduction and population growth are most sensitive to perturbations in survival of the limiting sex. Overall, our study suggests that sex-biased early survival may contribute toward mating system evolution and population persistence, with implications for both sexual selection theory and biodiversity conservation

High fidelity: extra-pair fertilisations in eight Charadrius plover species are not associated with parental relatedness or social mating system

Extra-pair paternity is a common reproductive strategy in many bird species. However, it remains unclear why extra-pair paternity occurs and why it varies among species and populations. Plovers (Charadrius spp.) exhibit considerable variation in reproductive behaviour and ecology, making them excellent models to investigate the evolution of social and genetic mating systems. We investigated inter- and intra-specific patterns of extra-pair parentage and evaluated three major hypotheses explaining extra-pair paternity using a comparative approach based on the microsatellite genotypes of 2049 individuals from 510 plover families sampled from twelve populations that constituted eight species. Extra-pair paternity rates were very low (0 to 4.1% of chicks per population). No evidence was found in support of the sexual conflict or genetic compatibility hypotheses, and there was no seasonal pattern of extra-pair paternity (EPP). The low prevalence of EPP is consistent with a number of alternative hypotheses, including the parental investment hypothesis, which suggests that high contribution to care by males restricts female plovers from engaging in extra-pair copulations. Further studies are needed to critically test the importance of this hypothesis for mate choice in plovers

Consequences of individual variation on population dynamics: a behavioural, molecular, and demographic study of Charadrius plovers

Eberhart-Phillips L. Consequences of individual variation on population dynamics: a behavioural, molecular, and demographic study of Charadrius plovers. Bielefeld; 2017

Conservation challenges of a sink: the viability of an isolated population of the Snowy Plover

Eberhart-Phillips L, Colwell M. Conservation challenges of a sink: the viability of an isolated population of the Snowy Plover. Bird Conservation International. 2014;24(3):327-341.Source-sink dynamics are easily overlooked when formulating recovery objectives for threatened species. This could lead to unrealistic criteria imposed on sink populations, which in turn might restrict an entire metapopulation from being delisted. Therefore, an understanding of the viability of subpopulations within the context of a metapopulation is needed to develop appropriate recovery objectives. Consequently, we used 11 years of mark-recapture, productivity, and movement data to analyse the viability of a small, geographically isolated population of the Snowy Plover Charadrius nivosus, a shorebird listed as threatened under the U.S. Endangered Species Act. Simulations confirmed that the focal population in northern California is a sink that relies upon immigrants from neighbouring populations. Furthermore, these source populations will increase within the next 50 years and are likely to achieve the delisting requirements. However, the northern California population is unlikely to reach the delisting criteria given the current vital rate estimations. Management scenarios demonstrated that lethal predator removal and reducing human disturbance facilitate population recovery and may partially alleviate the reliance upon immigration. However, the use of nest exclosures reduced population growth because they are known to compromise adult survival. These results highlight the importance of maintaining viable source populations and re-evaluating the recovery objectives of metapopulations with active sinks

Apparent Survival of Snowy Plovers (Charadrius nivosus) Varies with Reproductive Effort and Year and between Sexes

Life history theory predicts a tradeoff between reproductive effort and survival, which suggests that some management practices aimed at increasing productivity may compromise population growth. We analyzed a 10-year data set of 225 individually marked Snowy Plovers (Charadrius nivosus), a threatened shorebird, to determine whether individual reproductive effort was correlated with low apparent survival. Most adults resided in the population an average of 2 years (range: 1–10 years), during which females laid 3–60 eggs, and both males and females invested considerable time in incubation and brooding. Apparent survival varied annually and was higher for males than for females. Contrary to theory, we found no evidence that increased reproductive effort, either current or cumulative, compromised survival. Instead, apparent survival was correlated positively with incubation time, which may be related to either high-quality individuals having high reproductive rates and high survival or permanent emigration of failed breeders (who incubated for shorter intervals). Although our results suggest that some predator management practices (e.g., nest exclosures) aimed at increasing productivity will not compromise survival in a subsequent year, we caution that these same practices may have serious negative consequences for population growth if (1) reproductive effort does not translate into higher per capita fledging success and (2) direct mortality of adults results from the practice.This article is from Auk 130 (2013): 725, doi:10.1525/auk.2013.13147. Poste with permission.</p