Find research datasets worth reusing

Data from: Workforce effects and the evolution of complex sociality in wild Damaraland mole rats

Explaining the evolution of eusocial and cooperatively breeding societies demands that we understand the effects of workforce size on the reproductive success of breeders. This challenge has yet to be addressed in the family that arguably exhibits the most extreme outcomes of vertebrate social evolution, the African mole rats (Bathyergidae), leaving the ultimate causes of their many unusual adaptations open to debate. Here we report—using a 14-year field study of wild Damaraland mole rats, Fukomys damarensis—that workers appear to have strong but unusual effects on offspring. Groups with larger workforces exhibited substantially higher rates of offspring recruitment while maintaining high juvenile survival rates, relationships that may have favored the evolution of the delayed dispersal, cooperation, morphological specialization, and unusual patterns of longevity that characterize such societies. Offspring reared by larger workforces also showed slower growth, however. That reduced offspring growth in larger groups has also been documented under ad lib. food conditions in the laboratory raises the possibility that this reflects socially induced growth restraint rather than simple constraints on resource availability. Our findings shed new light on the evolution of complex sociality in this enigmatic clade and highlight further departures from the norms reported for other cooperative vertebrates.

Data from: No evidence for MHC class I based disassortative mating in a wild population of great tits

Genes of the major histocompatibility complex (MHC) are regarded as a potentially important target of mate choice due to the fitness benefits that may be conferred to the offspring. According to the complementary genes hypothesis, females mate with MHC dissimilar males to enhance the immunocompetence of their offspring or to avoid inbreeding depression. Here, we investigate whether selection favours a preference for maximally dissimilar or optimally dissimilar MHC class I types, based on MHC genotypes, average amino acid distances and the functional properties of the antigen-binding sites (MHC supertypes); and whether MHC type dissimilarity predicts relatedness between mates in a wild great tit population. In particular, we explore the role that MHC class I plays in female mate choice decisions while controlling for relatedness and spatial population structure, and examine the reproductive fitness consequences of MHC compatibility between mates. We find no evidence for the hypotheses that females select mates on the basis of either maximal or optimal MHC class I dissimilarity. A weak correlation between MHC allele sharing and relatedness, and between MHC supertype sharing and relatedness suggests that MHC dissimilarity at functional variants may not provide an effective index of relatedness. Moreover the reproductive success of pairs did not vary with MHC dissimilarity. Our results provide no support for the suggestion that selection favours, or that mate choice realises, a preference for complimentary MHC types.

Data from: Oxidative damage and antioxidant defence are assay and tissue dependent both in captive and in wild-caught bank voles (Myodes glareolus) before and after reproduction

1. Reproduction is costly and life-history theory predicts that current parental investment will result in lower survival or decreased future reproduction. The physiological mechanisms mediating the link between reproduction and survival are still under debate and elevated oxidative damage during reproduction has been proposed as a plausible candidate. 2. Previous studies of oxidative stress during reproduction in animals under natural conditions have been restricted to analyses of blood. Herein, we measured the level of oxidative damage to lipids (thiobarbituric-acid-reactive substances) and proteins (carbonyls) in the liver, kidneys, heart and skeletal muscles in free-living bank vole females from spring and autumn generations, before and after reproduction. Antioxidant defence in the liver and kidneys was also determined. We expected oxidative damage to tissues and hypothesized that the damage would be more uniform between tissues in wild animals compared to those breeding under laboratory conditions. 3. Considering all combinations of markers/tissues/generations, oxidative damage in females did not differ before and after reproduction in 12 comparisons, was lower after reproduction in 3 comparisons, and was higher after breeding in one comparison. The total glutathione was significantly increased after reproduction only in the liver of the autumn generation and there was no change in catalase activity. 4. Our results confirm – for the first time in the field – previous observations from laboratory studies that there is no simple link between oxidative stress and reproduction and that patterns depend on the tissue and marker being studied. Overall however, our study does not support the hypothesis that the cost of reproduction in bank voles is mediated by oxidative stress in these tissues.

Data from: Negative effects of pesticides on wild bee communities can be buffered by landscape context

Wild bee communities provide underappreciated but critical agricultural pollination services. Given predicted global shortages in pollination services, managing agroecosystems to support thriving wild bee communities is, therefore, central to ensuring sustainable food production. Benefits of natural (including semi-natural) habitat for wild bee abundance and diversity on farms are well documented. By contrast, few studies have examined toxicity of pesticides on wild bees, let alone effects of farm-level pesticide exposure on entire bee communities. Whether beneficial natural areas could mediate effects of harmful pesticides on wild bees is also unknown. Here, we assess the effect of conventional pesticide use on the wild bee community visiting apple (Malus domestica) within a gradient of percentage natural area in the landscape. Wild bee community abundance and species richness decreased linearly with increasing pesticide use in orchards one year after application; however, pesticide effects on wild bees were buffered by increasing proportion of natural habitat in the surrounding landscape. A significant contribution of fungicides to observed pesticide effects suggests deleterious properties of a class of pesticides that was, until recently, considered benign to bees. Our results demonstrate extended benefits of natural areas for wild pollinators and highlight the importance of considering the landscape context when weighing up the costs of pest management on crop pollination services.

Data from: How maternal investment varies with environmental factors and the age and physiological state of wild tsetse Glossina pallidipes and Glossina morsitans morsitans

Theory suggests females should optimize resource allocation across reproductive bouts to maximize lifetime reproduction, balancing current and future reproductive efforts according to physiological state and projected survival and reproduction. Tests of these ideas focus on long-lived vertebrates: few measure age-related reproductive output in iteroparous invertebrates, or partition reserves between those allocated to offspring versus mothers. We investigated how maternal age, and environmental and physiological factors influence reproductive investment in wild tsetse, Glossina pallidipes Austen and G. morsitans morsitans Westwood. Tsetse provide a tractable system to measure reproductive allocation. Females exhibit high maternal investment, producing single, large offspring that rely exclusively on maternal reserves. We find that mothers in better physiological condition and experiencing cooler temperatures produce larger offspring. Pupal size increases significantly but weakly with age. In both species, females with less fat invest proportionately more in offspring. Post-partum fat decreases in flies with badly frayed wings: poor flight capability may limit their feeding efficiency, or they may sacrifice more reserves as a terminal investment. Our results support evidence that offspring size increases with maternal size, investment depends on the environment, and females with lower chances of future reproduction invest more into current offspring. We discuss the implications of maternal effects for predicting vector population responses to environmental change.

opencc-zeroDec 2010View details →

Data from: Spatial and temporal patterns of neutral and adaptive genetic variation in the endangered African wild dog (Lycaon pictus)

Deciphering patterns of genetic variation within a species is essential for understanding population structure, local adaptation and differences in diversity between populations. Whilst neutrally evolving genetic markers can be used to elucidate demographic processes and genetic structure, they are not subject to selection and therefore are not informative about patterns of adaptive variation. As such, assessments of pertinent adaptive loci, such as the immunity genes of the Major Histocompatibility Complex (MHC), are increasingly being incorporated into genetic studies. In this study we combined neutral (microsatellite, mtDNA) and adaptive (MHC class II DLA-DRB1 locus) markers to elucidate the factors influencing patterns of genetic variation in the African wild dog (Lycaon pictus); an endangered canid that has suffered extensive declines in distribution and abundance. Our genetic analyses found all extant wild dog populations to be relatively small (Ne < 30). Furthermore, through coalescent modelling, we detected a genetic signature of a recent and substantial demographic decline, which correlates with human expansion, but contrasts with findings in some other African mammals. We found strong structure of wild dog populations, indicating the negative influence of extensive habitat fragmentation and loss of gene flow between habitat patches. Across populations we found that the spatial and temporal structure of microsatellite and MHC diversity were correlated, and strongly influenced by demographic stability and population size, indicating the effects of genetic drift in these small populations. Despite this correlation, we detected signatures of selection at the MHC, implying that selection has not been completely overwhelmed by genetic drift.

opencc-zeroFeb 2020View details →

Data from: Gradual replacement of wild bees by honeybees in flowers of the Mediterranean Basin over the last 50 years

<p>Evidence for pollinator declines largely originates from mid-latitude regions in North America and Europe. Geographical heterogeneity in pollinator trends combined with geographical biases in pollinator studies, can produce distorted extrapolations and limit understanding of pollinator responses to environmental changes. In contrast to the declines experienced in some well-investigated European and North American regions, honeybees seem to have increased recently in some areas of the Mediterranean Basin. Since honeybees can have negative impacts on wild bees, it was hypothesized that a biome-wide alteration in bee pollinator assemblages may be underway in the Mediterranean Basin involving a reduction in the relative number of wild bee pollinators. This hypothesis was tested using published quantitative data on bee pollinators of wild and cultivated plants from studies conducted between 1963-2017 in 13 Mediterranean countries. The density of honeybee colonies increased exponentially and wild bees were gradually replaced by honeybees in flowers of wild and cultivated plants. The proportion of wild bees at flowers was four times greater than that of honeybees at the beginning of the period, the proportions of both groups becoming roughly similar fifty years later. The Mediterranean Basin is a world biodiversity hotspot for wild bees and wild bee-pollinated plants, and the ubiquitous rise of honeybees to dominance as pollinators could in the long run undermine the diversity of plants and wild bees in the region.</p>

opencc-zeroJul 2019View details →

When more is not merrier: using wild population dynamics to understand the effect of density on ex situ seahorse mating behaviors

Seahorses are one of the most iconic examples of a monogamous species in the animal kingdom. Documenting monogamous behaviors of seahorses have proven to be quite complicated to study in the wild because of their low population densities and cryptic habits. Another challenge involves interpreting these behaviors in captivity because recreating realistic densities of wild populations in the laboratory can be difficult due to their patchy distributions. This study investigates the relationship between stocking density and mating and competitive behavior from the context of the field biology of the dwarf seahorse, Hippocampus zosterae (Jordan & Gilbert). Animals were housed in 38 liter tanks at a range of densities and sex ratios (from 2-8 animals per tank), and their reproductive and other social behaviors were monitored from tank introduction through copulation. At low tank densities and even sex ratios but comparatively high field densities, activity level in trials was low. A higher level of males in tanks across all densities increased competition, activity levels, and aggression leading to partial egg transfers and failed pregnancies, resulting in lower reproductive success. Across seahorse species, mean and maximum wild densities were consistently lower than those used in captive breeding, with adult sex ratios that were significantly female biased. However, significant variation exists in wild seahorse densities across species, with higher densities detected in focal/mark recapture studies and on artificial habitat structures than reported with belt transect sampling techniques. Interchange of knowledge gained in both captive and wild contexts will allow us to better understand the biology of this genus, and improve reproduction in captivity. Interpreting captive reproductive behaviors of seahorses within various densities reported from natural populations will help us predict the impact of conservation efforts and increase the likelihood of long-term persistence of populations for this threatened genus.

opencc-zeroDec 2015View details →

Data from: Cumulative early life adversity predicts longevity in wild baboons

In humans and other animals, harsh circumstances in early life predict morbidity and mortality in adulthood. Multiple adverse conditions are thought to be especially toxic, but this hypothesis has rarely been tested in a prospective, longitudinal framework, especially in long-lived mammals. Here we use prospective data on 196 wild female baboons to show that cumulative early adversity predicts natural adult lifespan. Females who experience ≥3 sources of early adversity die a median of 10 years earlier than females who experience ≤1 adverse circumstances (median lifespan is 18.5 years). Females who experience the most adversity are also socially isolated in adulthood, suggesting that social processes partially explain the link between early adversity and adult survival. Our results provide powerful evidence for the developmental origins of health and disease and indicate that close ties between early adversity and survival arise even in the absence of health habit and health care-related explanations.

opencc-zeroDec 2012View details →

Data from: Evolutionary and dispersal history of Eurasian wild mice Mus musculus clarified by more extensive geographic sampling of mitochondrial DNA

We examined sequence variation of mitochondrial DNA control region and cytochrome b gene of the house mouse (Mus musculus sensu lato) drawn from ca. 200 localities, with 290 new samples drawn primarily from previously unsampled portions of their Eurasian distribution and with the objective of further clarifying evolutionary episodes of this species before and after the onset of human-mediated long-distance dispersals. Phylogenetic analysis of the expanded data detected five equally distinct clades, with geographic ranges of northern Eurasia (musculus, MUS), India and Southeast Asia (castaneus, CAS), Nepal (unspecified), western Europe (domesticus, DOM), and Yemen (gentilulus). Our results confirm previous suggestions of Southwestern Asia as the likely place of origin of M. musculus and the region of Iran, Afghanistan, Pakistan, and northern India, specifically as the ancestral homeland of CAS. The divergence of the subspecies lineages and of internal sublineage differentiation within CAS were estimated to be 0.37-0.47 and 0.14-0.23 million years ago (mya), respectively, assuming a split of M. musculus and Mus spretus at 1.7 mya. Of four CAS sublineages detected, only one extends to eastern parts of India, Southeast Asia, Indonesia, Philippines, South China, Northeast China, Primorye, Sakhalin and Japan, implying a dramatic range expansion of CAS out of its homeland during an evolutionary short time, perhaps associated with the spread of agricultural practices. Multiple and non-coincident eastward dispersal events of MUS sublineages to distant geographic areas, such as northern China, Russia, and Korea, are inferred, with the possibility of several different routes.

opencc-zeroDec 2016View details →

Data from: Species integrity enhanced by a predation cost to hybrids in the wild

Species integrity can be challenged, and even eroded, if closely related species can hybridize and produce fertile offspring of comparable fitness to that of parental species. The maintenance of newly diverged or closely related species therefore hinges on the establishment and effectiveness of pre- and/or post-zygotic reproductive barriers. Ecological selection, including predation, is often presumed to contribute to reduced hybrid fitness, but field evidence for a predation cost to hybridization remains elusive. Here we provide proof-of-concept for predation on hybrids being a postzygotic barrier to gene flow in the wild. Cyprinid fishes commonly produce fertile, viable hybrid offspring and therefore make excellent study organisms to investigate ecological costs to hybrids. We electronically tagged two freshwater cyprinid fish species (roach Rutilus rutilus and bream Abramis brama) and their hybrids in 2005. Tagged fish were returned to their lake of origin, exposing them to natural predation risk from apex avian predators (great cormorant, Phalacrocorax carbo). Scanning for regurgitated tags under cormorant roosts 3–4 years later identified cormorant-killed individual fish and allowed us to directly test for a predation cost to hybrids in the wild. Hybrid individuals were found significantly more susceptible to cormorant predation than individuals from either parental species. Such ecological selection against hybrids contributes to species integrity, and can enhance species diversification.

Data from: Prediction and attenuation of seasonal spillover of parasites between wild and domestic ungulates in an arid mixed-use system

1.Transmission of parasites between host species affects host population dynamics, interspecific competition, and ecosystem structure and function. In areas where wild and domestic herbivores share grazing land, management of parasites in livestock may affect or be affected by sympatric wildlife due to cross-species transmission. 2.We develop a novel method for simulating transmission potential based on both biotic and abiotic factors in a semi-arid system in Botswana. Optimal timing of antiparasitic treatment in livestock is then compared under a variety of alternative host scenarios, including seasonally migrating wild hosts. 3.In this region, rainfall is the primary driver of seasonality of transmission, but wildlife migration leads to spatial differences in the effectiveness of treatment in domestic animals. Additionally, competent migratory wildlife hosts move parasites across the landscape. 4.Simulated transmission potential matches observed patterns of clinical disease in the study area. Increased wildlife contact is correlated with a decrease in disease, suggesting that noncompetent wild hosts may attenuate transmission by removing infective parasite larvae from livestock pasture. 5.Optimising the timing of treatment according to within-year rainfall patterns was considerably more effective than treating at a standard time of year. By targeting treatment in this way, efficient control can be achieved, mitigating parasite spillover from wildlife where it does occur. 6.Synthesis and applications: This model of parasite transmission potential enables evidence-based management of parasite spillover between wild and domestic species in a spatio-temporally dynamic system. It can be applied in other mixed-use systems to mitigate parasite transmission under altered climate scenarios or changes in host ranges.

opencc-zeroDec 2013View details →

Data from: Does human-induced hybridization have long-term genetic effects? Empirical testing with domesticated, wild and hybridized fish populations

Current conservation practices exclude human-generated hybridized populations from protection, as the genetic effects of hybridization in the wild have been observed to be long-lasting based on neutral genetic markers and are considered potentially irreversible. Theory, however, predicts otherwise for genes under selection. We transplanted combinations of wild, domesticated and hybridized populations of a fish species to new environments. We then compared survival, phenotypic variation and plasticity to determine whether hybridization affects adaptive potential after multiple generations of selection in the wild. Although the fitness of our hybridized populations at the onset of hybridization cannot be assessed, our results suggest that within five to eleven generations, selection can remove introduced foreign genes from wild populations that have hybridized with domesticated conspecifics. The end result is hybridized populations that, in terms of survival, phenotypic plasticity, mean trait expression and overall general responses to environmental change, closely resemble neighbouring wild populations. These results have important implications for considering the potential conservation value of hybridized populations and illustrate the effectiveness of selection in a local environment.

opencc-zeroDec 2010View details →

Data from: Predation-associated differences in sex-linkage of wild guppy coloration

Evolutionary theory predicts that the sex-linkage of sexually selected traits can influence the direction and rate of evolutionary change, and also itself be subject to selection. Theory abounds on how sex-specific selection, mate choice, or other phenomena should favor different types of sex-linked inheritance, yet evidence in nature remains limited. Here we use hormone assays in Trinidadian guppies to explore the extent to which linkage of male coloration differs among populations adapted to varying predation regimes. Results show there is consistently higher degree of X- and autosomal linkage in body coloration among populations adapted to low-predation environments. More strikingly, analyses of an introduced population of guppies from a high to a low predation environment suggest that this difference can change in 50 years or less.

opencc-zeroDec 2016View details →

Data from: Host resistance and pathogen aggressiveness are key determinants of coinfection in the wild

Coinfection, whereby the same host is infected by more than one pathogen strain, may favor faster host exploitation rates as strains compete for the same limited resources. Hence, coinfection is expected to have major consequences for pathogen evolution, virulence and epidemiology. Theory predicts genetic variation in host resistance and pathogen infectivity to play a key role in how coinfections are formed. The limited number of studies available have demonstrated coinfection to be a common phenomenon, but little is known about how coinfection varies in space, and what its determinants are. Our aim is to understand how variation in host resistance and pathogen infectivity and aggressiveness contribute to how coinfections are formed in the interaction between fungal pathogen Podosphaera plantaginis and Plantago lanceolata. Our phenotyping study reveals that more aggressive strains are more likely to form coinfections than less aggressive strains in the natural populations. In the natural populations most of the variation in coinfection is found at the individual plant level, and results from a common garden study confirm the prevalence of coinfection to vary significantly among host genotypes. These results show that genetic variation in both the host and pathogen populations are key determinants of coinfection in the wild.

opencc-zeroDec 2015View details →

Data from: Socioecological predictors of immune defenses in wild spotted hyenas

Social rank can profoundly affect many aspects of mammalian reproduction and stress physiology, but little is known about how immune function is affected by rank and other socioecological factors in free-living animals. In this study, we examine the effects of sex, social rank and reproductive status on immune function in long-lived carnivores that are routinely exposed to a plethora of pathogens, yet rarely show signs of disease. Here, we show that two types of immune defences, complement-mediated bacterial killing capacity (BKC) and total IgM, are positively correlated with social rank in wild hyenas, but that a third type, total IgG, does not vary with rank. Female spotted hyenas, which are socially dominant to males in this species, have higher BKC, and higher IgG and IgM concentrations, than do males. Immune defences are lower in lactating than pregnant females, suggesting the immune defences may be energetically costly. Serum cortisol and testosterone concentrations are not reliable predictors of basic immune defences in wild female spotted hyenas. These results suggest that immune defences are costly and multiple socioecological variables are important determinants of basic immune defences among wild hyenas. The effects of these variables should be accounted for when attempting to understand disease ecology and immune function.

opencc-zeroDec 2016View details →

Data from: Linking innate immunogenetic variation with phenotypic traits in a wild population of tree swallows, Tachycineta bicolor

Unravelling the genetic basis of phenotypic variation among individuals is an important step in our understanding of evolution. Recent studies of innate immune genes, such as β -defensins, revealed that these genes had high levels of polymorphism. However, researchers have yet to quantify the effects of such variability on immune responses and fitness-related traits in wild populations. In this study, we assessed how the variability at six avian β -defensin (AvBD) genes was linked to an immune function and reproductive success in adult tree swallows (Tachycineta bicolor). We investigated the links between genetic variations using single nucleotide polymorphisms at AvBD genes, immune function as the bacterial killing ability (BKA) and fledging success. We assessed how female immunogenetics were linked to the presence of eggshell bacteria in their clutches and hatching success. We found weak associations between the presence of AvBD genes, BKA and eggshell bacteria. Our results suggested that homozygosity at some loci may be advantageous for defence against bacteria. Variability at β -defensin genes was not related to either hatching or fledging success. BKA of parents was positively linked with fledging success. More studies are needed to assess whether or not β -defensin genes are significantly affecting fitness-related traits in wild populations.

Data from: Structure and extent of DNA methylation-based epigenetic variation in wild emmer wheat (T. turgidum ssp. dicoccoides) populations

Background: The genetic structure and differentiation of wild emmer wheat suggests that genetic diversity is eco-geographically structured. However, very little is known about the structure and extent of the heritable epigenetic variation and its influence on local adaptation in natural populations. Results: The structure and extent of the heritable methylation-based epigenetic variation were assessed within and among natural populations of Triticum turgidum ssp. dicoccoides. We used methylation sensitive amplified polymorphism (MSAP) and transposon methylation display (TMD) techniques, to assess the methylation status of random genomic CCGG sites and CCGG sites flanking transposable elements (TEs), respectively. Both techniques were applied to the DNA of 50 emmer accessions which were collected from five different geographically isolated regions. In order to ensure the assessment of heritable epigenetic variation, all accessions were grown under common garden conditions for two generations. In all accessions, the difference in methylation levels of CCGG sites, including CCGG sites that flanked TEs, were not statistically significant and relatively high, ranging between 46 and 76 %. The pattern of methylation was significantly different among accessions, such that clear and statistically significant population-specific methylation patterns were observed. Conclusion: In this study, we have observed population-unique heritable methylation patterns in emmer wheat accessions originating from five geographically isolated regions. Our data indicate that methylation-based epigenetic diversity might be eco-geographically structured and might be partly determined by climatic and edaphic factors.

Data from: Impact of sexually antagonistic genital morphologies on female reproduction and wild population demography

Sexual conflict is a strong driver of evolution. The evolutionary outcomes of sexual conflict can, in turn, influence ecological processes within populations, e.g., demography. However, evidence for the latter hypothesis is scarce, especially in the wild. Here, we show that sexual conflict is associated with demographic processes determining population size in the ground beetle Carabus insulicola with elaborate male and female genitalia, based on individual- and population-level analyses. We found that sexually antagonistic selection can operate on the genitalia: longer male genitalia can be beneficial in sperm competition but decrease female reproductive success with increased egg dumping, while longer female genitalia are resistant to this male harassment via decreased egg dumping and increased fertilization rate. As expected from sexually antagonistic coevolution due to sexual conflict, we detected coevolutionary divergence between male and female genital sizes among populations. In parallel with decrease in female reproductive success, more harmful males with longer genitalia and less resistant females with shorter genitalia were related to small effective population sizes. Thus, sexual conflict may promote coevolutionary diversification between sexual traits, and this was associated with a demographic process. Our findings provide an insight into sex-driven eco-evolutionary dynamics in the wild.