Javier Pérez-González

Female‐biased dispersal under conditions of low male mating competition in a polygynous mammal

Sex‐biased dispersal is a common phenomenon in birds and mammals. Competition for mates has been argued to be an important selective pressure favouring dispersal. Sexual differences in the level of intrasexual competition may produce asymmetries in the costs‐benefits balance of dispersal and philopatry for males and females, which may favour male‐biased dispersal in polygynous species such as most mammals. This being the case, condition‐dependent dispersal predicts that male‐bias should decrease if mating competition relaxes. We test this expectation for red deer, where male‐biased dispersal is the norm. In southwestern Spain, red deer populations located in nonfenced hunting estates presented altered structures with sex ratio strongly biased to females and high proportion of young males. As a consequence, mate competition in these populations was lower than in other, most typical red deer populations. We found that, under such conditions of altered population structure, dispersal was female‐biased rather than male‐biased. Additionally, mate competition positively related to male dispersal but negatively to female dispersal. Other factors such as resource competition, age of individuals and sex ratio were not related to male or female dispersal. Males may not disperse if intrasexual competition is low and then females may disperse as a response to male philopatry. We propose hypotheses related to female mate choice to explain female dispersal under male philopatry. The shift of the sex‐biased dispersal pattern along the gradient of mate competition highlights its condition‐dependence as well as the interaction between male and female dispersal in the evolution of sex‐biased dispersal.

Polygyny can increase rather than decrease genetic diversity contributed by males relative to females: evidence from red deer

Polygyny is expected to erode genetic variability by reducing the diversity of genetic contribution of males to the next generation, although empirical evidence shows that genetic variability in polygynous populations is not lost as rapidly as expected. We used microsatellite markers to study the genetic variability transmitted by mothers and fathers to offspring during a reproductive season in wild populations of a polygynous mammal, the red deer. Contrary to expectations, we found that males contributed more genetic diversity than females. Also, we compared study populations with different degrees of polygyny to find that polygyny was not related to a decrease in genetic diversity contributed by males. On the contrary, when population genetic diversity was relatively low, polygyny associated with higher genetic diversity of paternal lineage. Our results show that sexual selection, by favouring heterozygote individuals, may compensate the potential reduction of effective population size caused by polygyny, thus contributing to explain why genetic diversity is not depleted in polygynous systems.

Low Heterozygosity at Microsatellite Markers in Iberian Red Deer with Small Antlers

Deer antlers are costly structures subjected to directional sexual selection that may be sensitive to heterozygosity. However, a relationship between heterozygosity and antler development has only been found for select protein-coding loci and MHC genes in one deer species (the white-tailed deer Odocoileus virginianus). Here, we study the relationship between multilocus heterozygosity at 11 microsatellite markers and antler size (AS) in a sample of 367 Iberian red deer males (Cervus elaphus hispanicus) from two study areas with different ecological and genetic conditions. We found that males with very small antlers (10% of the sampled individuals with the lowest values of AS) had lower levels of heterozygosity than those with bigger antlers (significant effect in an analysis of variance, P = 0.011). This relationship was noticeable mainly in situations of low genetic diversity, where the differences in heterozygosity between groups of males were greater. Finally, we conducted analyses to address the hypotheses proposed by the heterozygosity-fitness correlation, and we found the local effect as the most likely hypothesis. Our findings reveal an expected but not previously detected association between low heterozygosity and reduced AS, with implications for red deer evolution and management.

Parents' genetic dissimilarity and offspring sex in a polygynous mammal.

Offspring quality may benefit from genetic dissimilarity between parents. However, genetic dissimilarity may trade‐off with additive genetic benefits. We hypothesized that when sexual selection produces sex‐specific selective scenarios, the relative benefits of additive genetic vs. dissimilarity may differ for sons and daughters. Here we study a sample of 666 red deer (Cervus elaphus) microsatellite genotypes, including males, females and their foetuses, from 20 wild populations in Spain (the main analyses are based on 241 different foetuses and 190 mother‐foetus pairs). We found that parental lineages were more dissimilar in daughters than in sons. On average, every mother was less related to her mate than to the sample of fathers in the population when producing daughters not sons. Male foetuses conceived early in the rutting season were much more inbred than any other foetuses. These differences maintained through gestation length, ruling out intrauterine mortality as a cause for the results, and indicating that the potential mechanism producing the association between parents’ dissimilarity and offspring sex should operate close to mating or conception time. Our findings highlight the relevance of considering the sex of offspring when studying genetic similarity between parents.

Selective culling of Iberian red deer stags (Cervus elaphus hispanicus) by selective montería in Spain

Hunting can affect animal populations not only by increasing mortality but also by introducing selection components associated with particular features of individuals. In addition to the most widespread hunting system in Spain for Iberian red deer stags (Cervus elaphus hispanicus) called montería, there are also selective monterías aimed at culling poor-trophy males in order to improve the average quality of the trophies for commercial hunt. This way of removing poor-trophy males contrasts with the most common procedure of shooting individual males by selective stalking that is used in other areas of Europe. Also, due to the hunting procedure by which most deer are shot while running chased by dogs, it is doubtful whether hunters are actually producing a selective impact on deer populations. In this paper, we compare data of males shot in commercial montería and in selective montería in Southern Spain. We found that males in selective montería were smaller in body size and in antler size than in commercial hunts, even correcting by age, although the selective effect was stronger at some ages. We discuss the implications of this practice for sustainable use and conservation.

Microsatellite markers for identification and parentage analysis in the European wild boar (Sus scrofa)

BackgroundThe wild boar (Sus scrofa) is among the most widespread mammal species throughout the old world. Presently, studies concerning microsatellites in domestic pigs and wild boars have been carried out in order to investigate domestication, social behavior and general diversity patterns among either populations or breeds. The purpose of the current study is to develop a robust set of microsatellites markers for parentage analyses and individual identification.FindingsA set of 14 previously reported microsatellites markers have been optimized and tested in three populations from Hungary, Portugal and Spain, in a total of 167 samples. The results indicate high probabilities of exclusion (0.99999), low probability of identity (2.0E-13 – 2.5E-9) and a parentage assignment of 100%.ConclusionsOur results demonstrate that this set of markers is a useful and efficient tool for the individual identification and parentage assignment in wild boars.

Relative Effect of Food Supplementation and Natural Resources on Female Red Deer Distribution in a Mediterranean Ecosystem

Abstract Supplementary feeding is a widespread game management practice in several red deer (Cervus elaphus) populations, with important potential consequences on the biology of this species. In Mediterranean ecosystems food supplementation occurs in the rutting period, when it may change mating system characteristics. We studied the role of food supplementation relative to natural resources in the spatial distribution, aggregation, and mean harem size of females in Iberian red deer (Cervus elaphus hispanicus) during the rut. We studied 30 red deer populations of southwestern Spain, 63% of which experienced supplementary feeding. Using multivariate spatial analyses we found that food supplementation affected distribution of females in 95% of the populations in which it occurred. Green meadows present during the mating season acted as an important natural resource influencing female distribution. Additionally, the level of female aggregation and mean harem size were significantly higher in those populations in which food supplementation determined female distribution than in populations in which female distribution did not depend on supplementary feeding. Because female aggregation and mean harem size are key elements in sexual selection, supplementary feeding may constitute an important anthropogenic element with potential evolutionary implications for populations of Iberian red deer.

Population structure, habitat features and genetic structure of managed red deer populations

Management of game ungulates alters population structure and habitat features, with potential effects on genetic structure. Here, we study 26 red deer (Cervus elaphus) populations in Spain. We used census data and habitat features as well as genetic information at 11 microsatellite markers from 717 individuals. We found that metapopulations presented a distribution associated with forest interruptions. Within metapopulations, fences did not have a significant effect on red deer genetic structure. The metapopulations we studied presented similar population structure, but they differed in habitat features and genetic structure. The metapopulation with higher resource availability showed a genetic structure pattern in which genetic relatedness between geographically close individuals was high while relatedness between geographically distant individuals was low. Contrarily, the metapopulation with lower resource availability presented a genetic structure pattern in which the genetic relatedness between individuals of different populations was independent of the geographic distance. We discuss the possible connection between resource availability and genetic structure. Finally, we did not find any population or environmental variable related to genetic differentiation within metapopulations.

Combined Effects of Drought and Density on Body and Antler Size of Male Iberian Red Deer Cervus Elaphus Hispanicus: Climate Change Implications

Hunting management of red deer Cervus elaphus populations may tend to increase population densities to maximise annual yield. Some studies have shown that density and low winter temperatures affect red deer populations in central and northern Europe, but these results cannot be extrapolated to red deer populations in the Mediterranean region where the limiting season is summer instead of winter. The two regions are predicted to experience different climate change effects: while rainfall may increase in northern latitudes, heavier droughts are expected in the Mediterranean region. We studied red deer populations of different densities on 19 hunting estates in southern Spain during two years with contrasting precipitation levels. Our aim was to quantify the combined effects of drought and population density on the development of stags, which is the main economic objective of hunting management in these areas. We found that drought affected body and antler size negatively, and that the effects were more severe in populations of high density. On the basis of our results, we recommend reducing the current densities of red deer in southern Spain to maintain the economic and environmental sustainability of hunting exploitation in the context of global climate change.

Genetic Structure and Effective Population Sizes in European Red Deer (Cervus elaphus) at a Continental Scale: Insights from Microsatellite DNA

We analyzed more than 600 red deer (Cervus elaphus) from large parts of its European distribution range at 13 microsatellite loci, presenting the first continent-wide study of this species using nuclear markers. Populations were clearly differentiated (overall F ST = 0.166, Josts D est = 0.385), and the BAPS clustering algorithm yielded mainly geographically limited and adjacent genetic units. When forced into only 3 genetic clusters our data set produced a very similar geographic pattern as previously found in mtDNA phylogeographic studies: a western group from Iberia to central and parts of Eastern Europe, an eastern group from the Balkans to Eastern Europe, and a third group including the threatened relict populations from Sardinia and Mesola in Italy. This result was also confirmed by a multivariate approach to analyzing our data set, a discriminant analysis of principal components. Calculations of genetic diversity and effective population sizes (linkage disequilibrium approach) yielded the lowest results for Italian (Sardinia, Mesola; N e between 2 and 8) and Scandinavian red deer, in line with known bottlenecks in these populations. Our study is the first to present comparative nuclear genetic data in red deer across Europe and may serve as a baseline for future analyses of genetic diversity and structuring in this widespread ungulate.