Knappbryan7120

Overall, our results indicate that spatial structure is a relevant factor in predicting where sexually antagonistic alleles might be observed. We suggest that sex-specific dispersal ecology and demography can contribute to interspecific and intragenomic variation in sexual antagonism.AbstractGroups of social animals are often organized into dominance hierarchies that are formed through pairwise interactions. There is much experimental data on hierarchies, examining such things as winner, loser, and bystander effects, as well as the linearity and replicability of hierarchies, but there is a lack evolutionary analyses of these basic observations. Here I present a game theory model of hierarchy formation in which individuals adjust their aggressive behavior toward other group members through reinforcement learning. Individual traits such as the tendency to generalize learning between interactions with different individuals, the rate of learning, and the initial tendency to be aggressive are genetically determined and can be tuned by evolution. AD-5584 inhibitor I find that evolution favors individuals with high social competence, making use of individual recognition, bystander observational learning, and, to a limited extent, generalizing learned behavior between opponents when adjusting their behavior toward other group members. The results are in qualitative agreement with experimental data, for instance, in finding weaker winner effects compared to loser effects.AbstractEcogeographic rules provide a framework within which to test evolutionary hypotheses of adaptation. Gloger's rule predicts that endothermic animals should have darker colors in warm/rainy climates. This rule also predicts that animals should be more rufous in warm/dry climates, the so-called complex Gloger's rule. Empirical studies frequently demonstrate that animals are darker in cool/wet climates rather than in warm/wet climates. Furthermore, sensory ecology predicts that, to enhance crypsis, animals should be darker in darker light environments. We aimed to disentangle the effects of climate and light environments on plumage color in the large Neotropical passerine family Furnariidae. We found that birds in cooler and rainier climates had darker plumage even after controlling for habitat type. Birds in darker habitats had darker plumage even after controlling for climate. The effects of temperature and precipitation interact so that the negative effect of precipitation on brightness is strongest in cool temperatures. Finally, birds tended to be more rufous in warm/dry habitats but also, surprisingly, in cool/wet locales. We suggest that Gloger's rule results from complementary selective pressures arising from myriad ecological factors, including crypsis, thermoregulation, parasite deterrence, and resistance to feather abrasion.AbstractTheory predicts that allometric constraints on sound production should be stronger for the lower frequencies of vocalizations than for the higher frequencies, which could originate from an allometry for sound frequency bandwidth. Using song recordings of approximately 1,000 passerine species (from >75% passerine genera), we show a significantly steeper allometry for the lower song frequencies than for the higher song frequencies, resulting in a positive allometry of frequency bandwidth larger species can use wider bandwidths than smaller species. The bandwidth allometry exists in songbirds (oscines) but not in nonoscine passerines, indicating that it emerges from a combination of constraints to sound frequency production or transmission and the evolved behavior of oscines unlike the narrow bandwidths of most nonoscine songs, the learned songs of oscines often use wide bandwidths that can be limited by both lower and upper constraints to sound frequency. This bandwidth allometry has implications for several research topics in acoustic communication.AbstractIn angiosperms, perennials typically present much higher levels of inbreeding depression than annuals. One hypothesis to explain this pattern stems from the observation that inbreeding depression is expressed across multiple life stages in angiosperms. It posits that increased inbreeding depression in more long-lived species could be explained by differences in the way mutations affect fitness, through the life stages at which they are expressed. In this study, we investigate this hypothesis. We combine a physiological growth model and multilocus population genetics approaches to describe a full genotype-to-phenotype-to-fitness map. We study the behavior of mutations affecting growth or survival and explore their consequences in terms of inbreeding depression and mutation load. Although our results agree with empirical data only within a narrow range of conditions, we argue that they may point us toward the type of traits capable of generating high inbreeding depression in long-lived species-that is, traits under sufficiently strong selection, on which selection decreases sharply as life expectancy increases. Then we study the role deleterious mutations maintained at mutation-selection balance may play in the joint evolution of growth and survival strategies.AbstractNiche expansion is a critical step in the speciation process. Large brains linked to improved cognitive ability may enable species to expand their niches and forage in new ways, thereby promoting speciation. Despite considerable work on ecological divergence in brain size and its importance in speciation, relatively little is known about how brain shape relates to behavioral, ecological, and taxonomic diversity at macroevolutionary scales. This is due in part to inherent challenges with quantifying brain shape across many species. Here we present a novel, semiautomated approach for rapidly phenotyping brain shape using semilandmarks derived from X-ray computed microtomography scans. We then test its utility by parsing evolutionary trends within a diverse radiation of birds kingfishers (Aves Alcedinidae). Multivariate comparative analyses reveal that rates of brain shape evolution (but not beak shape) are positively correlated with lineage diversification rates. Distinct brain shapes are further associated with changes in body size and foraging behavior, suggesting both allometric and ecological constraints on brain shape evolution.