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opencc-zeroDec 2012View details →

Data from: Fine-scale genetic structure in a wild bird population: the role of limited dispersal and environmentally-based selection as causal factors

Individuals are typically not randomly distributed in space; consequently ecological and evolutionary theory depends heavily on understanding the spatial structure of populations. The central challenge of landscape genetics is therefore to link spatial heterogeneity of environments to population genetic structure. Here, we employ multivariate spatial analyses to identify environmentally induced genetic structures in a single breeding population of 1174 great tits Parus major genotyped at 4701 single-nucleotide polymorphism (SNP) loci. Despite the small spatial scale of the study relative to natal dispersal we found multiple axes of genetic structure. We built distance-based Moran's eigenvector maps to identify axes of pure spatial variation, which we used for spatial correction of regressions between SNPs and various external traits known to be related to fitness components (avian malaria infection risk, local density of conspecifics, oak tree density and altitude). We found clear evidence of fine-scale genetic structure, with 21, 7 and 9 significant SNPs respectively associated with infection risk by two species of avian malaria (Plasmodium circumflexum and P. relictum) and local conspecific density. Such fine-scale genetic structure relative to dispersal capabilities suggests ecological and evolutionary mechanisms maintain within-population genetic diversity in this population with the potential to drive micro-evolutionary change.

opencc-zeroDec 2014View details →

Data from: Differential proteomic responses of selectively bred and wild Sydney rock oyster populations exposed to elevated CO2

Previous work suggests that larvae from Sydney rock oysters that have been selectively bred for fast growth and disease resistance are more resilient to the impacts of ocean acidification than nonselected, wild-type oysters. In this study, we used proteomics to investigate the molecular differences between oyster populations in adult Sydney rock oysters and to identify whether these form the basis for observations seen in larvae. Adult oysters from a selective breeding line (B2) and nonselected wild types (WT) were exposed for 4 weeks to elevated pCO2 (856 μatm) before their proteomes were compared to those of oysters held under ambient conditions (375 μatm pCO2). Exposure to elevated pCO2 resulted in substantial changes in the proteomes of oysters from both the selectively bred and wild-type populations. When biological functions were assigned, these differential proteins fell into five broad, potentially interrelated categories of subcellular functions, in both oyster populations. These functional categories were energy production, cellular stress responses, the cytoskeleton, protein synthesis and cell signalling. In the wild-type population, proteins were predominantly upregulated. However, unexpectedly, these cellular systems were downregulated in the selectively bred oyster population, indicating cellular dysfunction. We argue that this reflects a trade-off, whereby an adaptive capacity for enhanced mitochondrial energy production in the selectively bred population may help to protect larvae from the effects of elevated CO2, whilst being deleterious to adult oysters.

opencc-zeroDec 2022View details →

Behavioural syndrome between boldness and aggressiveness and link with reproductive success in a wild bird population

Boldness, defined as the behavioural response of individuals when facing a risky situation, is a major personality trait and often phenotypically correlates with other behavioural traits, in particular aggressiveness, exploration behaviour and neophobia. Yet, whether such links result from among-individual correlations, i.e. form behavioural syndromes sensu stricto, is often ignored and whether such syndromes may yield individual fitness benefits, and thus be selected for, remains poorly explored. We measured boldness as the nest defence behaviour against a dummy nest predator in a natural population of a small passerine bird, the collared flycatcher, Ficedula albicollis, and investigated the existence of a behavioural syndrome between boldness and two other behavioural traits, aggressiveness (measured as the agonistic response to competitors) and neophobia (measured as the behavioural response to a novel object in a known environment). Then we assessed the links between this potential syndrome and reproductive success, measured as fledging and recruitment success. Boldness score differed between the sexes and depended on whether the partner was present during the test. Nevertheless, it was repeatable, showing that boldness can be considered as a personality trait in our population. We found a positive among-individual correlation between boldness and aggressiveness, showing the existence of a behavioural syndrome between both personality traits. This syndrome was related to reproductive success: the number of fledged young (but not recruitment probability) increased with one integrative value of the boldness–aggressiveness syndrome. Conversely, boldness score was not correlated with neophobia. Our results thus clearly reveal a behavioural syndrome between boldness and aggressiveness with possible consequences for reproductive success in the study population, and therefore raise the question of the evolutionary implications of such a behavioural syndrome.

opencc-zeroFeb 2023View details →

Data from: Use of an exotic host plant shifts immunity, chemical defense, and viral burden in wild populations of a specialist insect herbivore

Defense against natural enemies constitutes an important driver of herbivore host range evolution in the wild. Populations of the Baltimore checkerspot butterfly, Euphydryas phaeton (Nymphalidae), have recently incorporated an exotic plant, Plantago lanceolata (Plantaginaceae), into their dietary range. To understand the tritrophic consequences of utilizing this exotic host plant, we examined immune performance, chemical defense, and interactions with a natural entomopathogen (Junonia coenia densovirus, Parvoviridae) across wild populations of this specialist herbivore. We measured three immune parameters, sequestration of defensive iridoid glycosides (IGs), and viral infection load in field-collected caterpillars using either P. lanceolata or a native plant, Chelone glabra (Plantaginaceae). We found that larvae using the exotic plant exhibited reduced immunocompetence, compositional differences in IG sequestration, and higher in situ viral burdens compared to those using the native plant. On both host plants, high IG sequestration was associated with reduced hemocyte concentration in the larval hemolymph, providing the first evidence of incompatibility between sequestered chemical defenses and the immune response (i.e., the "vulnerable host" hypothesis) from a field-based study. However, despite this negative relationship between IG sequestration and cellular immunity, caterpillars with greater sequestration harbored lower viral loads. While survival of virus-infected individuals decreased with increasing viral burden, it ultimately did not differ between the exotic and native plants. These results provide evidence that (1) phytochemical sequestration may contribute to defense against pathogens even when immunity is compromised, and (2) herbivore persistence on exotic plant species may be facilitated by sequestration and its role in defense against natural enemies.

opencc-zeroMar 2023View details →

Data for: Immune genotypes, immune responses, and survival in a wild bird population

Individuals vary in their immune genotype, inbreeding coefficient f, immune responses, survival to adulthood, and adult longevity. However, whether immune genes predict survival or longevity, whether such relationships are mediated through immune responses, and how f affects immune genotype remain unclear. We use a wild song sparrow (Melospiza melodia) population in which survival to adulthood, adult longevity, and f were measured precisely, and in which immune responses have previously been assessed. We investigate four toll-like receptors (TLR) and the major histocompatibility complex (MHC) class IIB exon 2 genes. We test: a) whether immune genes predict fitness (survival to adulthood or adult longevity); b) whether immune genes predict immune response; c) whether immune response predicts fitness; and d) whether fitness, immune responses, or immune genotypes are correlated with f. We find that survival to adulthood is not associated with immune gene variation, but adult longevity is decreased by high MHC allele diversity (especially in birds that were relatively outbred), and by the presence of a specific MHC supertype. Immune responses were affected by specific immune genotypes. Survival to adulthood and adult longevity were not predicted by immune response, implying caution in the use of immune response as a predictor for fitness. We also found no relationship between f and immune genotype. This finding indicates that immune gene associations with longevity and immune response are not artefacts of f, and suggests that pathogen-mediated selection at functional loci can slow the loss of genetic variation arising from genetic drift and small population size.

opencc-zeroApr 2023View details →

Data from: Contrasting demographic responses to size-selective harvesting among neighboring wild fish populations

Sustainable harvesting of wild populations relies on evidence-based knowledge to predict harvesting outcomes for species and the ecosystems they inhabit. Although harvesting may elicit compensatory density-dependence, it is generally size-selective, which induces additional pressures that are challenging to forecast. Furthermore, responses to harvest may be population-specific and whether generalizable patterns exist remains unclear. Taking advantage of Parks Canada's mandate to remove introduced brook trout (Salvelinus fontinalis) to restore alpine lakes in Canadian parks, we experimentally applied standardized size-selective harvesting rates (the largest ~64% annually) for three consecutive summers in five populations with different initial size structures. Four unharvested populations were used as controls. At reduced densities, harvested and control populations exhibited similar density-dependent increases in specific growth, juvenile survival, and earlier maturation. However, size-selective harvesting simultaneously induced changes to size and age structure that contrasted among harvested populations. Average body length decreased in three of five harvested populations, whereas it tended to increase in control populations over the three years. We also detected contrasting, population-specific changes in body length variability and ultimately in length- and age-at-harvest in harvested populations but not controls. Overall, populations with smaller, more homogeneous body sizes, and living at high densities were most resilient to size-selective harvesting, exhibiting the smallest change in size-at-age. In contrast, large-bodied populations exhibited more substantial size-structure changes following selective harvesting: large-bodied populations experienced either stabilizing or disruptive pressures, when initial length variability was high or low, respectively. Synthesis and application: Our results show that within species, size-selective harvesting inherently leads to more risk and uncertainty when harvesting populations with larger and more varied body sizes than smaller-bodied populations with less range in body size. Our study supports prioritizing regulations that protect harvested populations with larger and more varied body sizes. Such a management strategy would reduce the likelihood of eliciting unpredictable or undesirable demographic changes to fish populations with these attributes.

opencc-zeroMay 2023View details →

Challenges of copro-parasitological surveys in wild Iberian ibex (Capra pyrenaica) populations addressed through a combination of molecular and statistical tools

Copro-parasitological surveys in wildlife face challenges due to the secretive nature of many species and the unknown performance of the diagnostic tests employed. To overcome these issues, we used a combination of hierarchical models (site-occupancy and N-mixture models) applied to copro-parasitological data obtained from faecal samples assigned to the host species by molecular methods in the Iberian ibex in north-western Iberian Peninsula. The aims were to compare the performance of four diagnostic tests (Mini-FLOTAC, McMaster, Willis flotation, and natural sedimentation) and to use this methodological approach (molecular analysis with hierarchical models) to better estimate positivity proportion and shedding intensity in a wild ibex population. Pooled faecal samples were collected, and those confirmed by molecular analyses to be the host species in question were included in the study. Hierarchical models confirmed different performances of each diagnostic test, with Mini-FLOTAC showing higher sensitivity for eimeriid coccidia, Willis flotation (for proportion positive) and McMaster (for shedding intensity) in gastrointestinal Strongylida, and equal performance of MiniFlotac/Willis flotation (for proportion positive) and MiniFlotac/McMaster (for shedding intensity) in Moniezia spp. This study employed a combination of molecular and statistical methods that improved the estimates of prevalence and shedding intensity and allowed us to compare the performance of four diagnostic tests while assessing the effect of covariates. Such improvements are critical to enhancing inference in non-invasive wildlife copro-parasitological studies.

FIGURE 4 in Lepanthes cordillerana (Orchidaceae) a new species and the landscape threats to its wild populations

FIGURE 4. Landscape-scale context analysis of Lepanthes cordillerana E.Restrepo, J.S.Moreno & Gal.-Tar. across the three Colombian Andean cordilleras. The boxplots show the median value, the 25th and 75th percentile range for locality (n= 5) across the 10 landscape size (100–2400 m radius). The circular dots represent the outliers in observed records of compositional turnover at each sampled plot. Each boxplot depicts A. Forest cover (percent of forest cover), B. fragmentation (number of patches in a landscape), and C. edge density (total length of forest edge divided by landscape size) context on each population. Prepared by Edicson Parra.

FIGURE 3 in Lepanthes cordillerana (Orchidaceae) a new species and the landscape threats to its wild populations

FIGURE 3. Distribution map of Lepanthes cordillerana E.Restrepo, J.S.Moreno & Gal.-Tar. and landscape-scale context of five populations. Green dots represent the recorded populations and digital elevation model from black 0–1000 m to light gray at 3500–5700 m in elevation. Insets show forest cover (dark green) and the matrix (light gray), white buffers depict the 10 landscape sizes where we calculated the habitat loss and configuration metrics. Prepared by Edicson Parra.

FIGURE 1 in Lepanthes cordillerana (Orchidaceae) a new species and the landscape threats to its wild populations

FIGURE 1. Illustration of Lepanthes cordillerana E.Restrepo, J.S.Moreno & Gal.-Tar. A. Habit. B. Flower C. Dissected perianth. D. Lip, lateral view. E. Expanded lip. F. pollinia and anther cap. Drawn by Sebastian Moreno from the plant that served as type (R. GalindoTarazona, P. Alzate & M. Espitia 1454).

FIGURE 2. Species comparison. A. Lepanthes cordillerana E.Restrepo, J.S in Lepanthes cordillerana (Orchidaceae) a new species and the landscape threats to its wild populations

FIGURE 2. Species comparison. A. Lepanthes cordillerana E.Restrepo, J.S.Moreno & Gal.-Tar. B. Lepanthes teres Luer. C. Lepanthes intonsa Luer. D. Lepanthes jubata Luer. E. Lepanthes protuberans Luer & R.P.Jesup. Photographs by Robinson Galindo-Tarazona (A), Luis Baquero (B). Sebastián Moreno (C, D) and Gerrit Verhellen (E). Prepared by Eugenio Restrepo.

opencc-zeroDec 2022View details →

Data from: probing variation in reaction norms in wild populations: the importance of reliable environmental proxies

Many traits are phenotypically plastic, i.e., the same genotype expresses different phenotypes depending on the environment. Genotypes and individuals can vary in their response to the environment and this genetic (G×E) and individual (I×E) variation in reaction-norm slopes can have important ecological or evolutionary consequences. Studies on I×E/G×E often fail to show slope variation, potentially due to the choice of the environmental covariate. Identifying the genuine environmental driver of phenotypic plasticity (the cue) is practically impossible and hence only proxies can be used. If the proxy is too weakly correlated with the cue, this may lead researchers to conclude there is little or no (variation in) plasticity, and hence lead to downwardly biased estimates of the potential for plastic responses (or evolutionary change in the slope) in response to environmental change. Alternatively, the Environment-Specific Mean phenotype (ESM) across individuals—which captures all environmental effects on the phenotype—as covariate should be less prone to such bias. We showed by simulation—after verifying the concept analytically—that using weakly correlated proxies indeed biased estimates of slope variation vis-à-vis the true cue downward but that ESM as a covariate held up well, even when multiple sources of I×E or an interaction between environments (I×E×E) existed in the data. Analysis of two real datasets revealed that estimated I×E and G×E, respectively, were more sizeable and precise when using ESM as opposed to reasonably informative environmental proxies. We argue that the ESM approach should be adopted by biologists as a yardstick in the study of (variation in) plasticity in the wild and that it may serve as a useful starting point for the search of better environmental proxies and unravelling complex I×E or G×E patterns.