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Parasitism generally imposes costs on victims, yet many victims appear to tolerate their parasites. We suggest that in some cases this may be because parasites provide victims with mitigating benefits, paradoxically giving rise to selection for advertisement rather than concealment by parasites. We investigate this possibility using the interaction between an avian kleptoparasite, the fork‐tailed...
Resurgent interest in the genetics of population divergence and speciation coincides with recent critical evaluation of species concepts and proposals for species delimitation. An important result of these parallel trends is a slight but important conceptual shift in focus away from species diagnoses based on prior species concepts or definitions, and toward analyses of the processes acting on lineages...
Recent work on the evolution of behaviour is set in a structured population, providing a systematic way to describe gene flow and behavioural interactions. To obtain analytical results one needs a structure with considerable regularity. Our results apply to such “homogeneous” structures (e.g., lattices, cycles, and island models). This regularity has been formally described by a “node‐transitivity”...
The telencephalon is proportionately larger in parrots than in galliformes (chicken‐like birds), whereas the midbrain tectum is proportionately smaller. We here test the hypothesis that the adult species difference in midbrain proportion is due to an evolutionary change in early brain patterning. In particular, we compare the size of the early embryonic midbrain between parakeets (Melopsittacus undulatus...
The honey bee population of South Africa is divided into two subspecies: a northern population in which queenless workers reproduce arrhenotokously and a southern one in which workers reproduce thelytokously. A hybrid zone separates the two, but on at least three occasions the northern population has become infested by reproductive workers derived from the southern population. These parasitic workers...
Mutual mate choice for homologous sexual display traits has been demonstrated in several recent studies yet little attention has been given to quantitative comparison of the strength and form of mate preferences between the sexes. Such comparisons may provide important insight into the evolution of mate choice for honest signals. In particular, because females generally provide the majority of resources...
The goal of this study is to develop a unifying theoretical framework to quantify the strength of reproductive isolation. We propose the use of the “effective recombination rate,” which measures how fast associations of genes are broken by interlocus recombination. Applying the well‐established theory of the effective migration rate, we derive two techniques to investigate the effective recombination...
DM‐W is a dominant, female‐specific, regulator of sex determination in the African clawed frog Xenopus laevis. This gene is derived from partial duplication of DMRT1, a male‐related autosomal gene. We set out to better understand sex determination in Xenopus by studying this pair of genes. We found that DM‐W evolved in Xenopus after divergence from the sister genus Silurana but before divergence of...
Multihost pathogens occur widely on both natural and agriculturally managed hosts. Despite the importance of such generalists, evolutionary studies of host–pathogen interactions have largely focused on tightly coupled interactions between species pairs. We characterized resistance in a collection of Arabidopsis thaliana hosts, including 24 accessions collected from the Midwest USA and 24 from around...
A link between urban living and disease is seen in recent and historical records, but the presence of this association in prehistory has been difficult to assess. If the transition to urban living does result in an increase in disease‐based mortality, we might expect to see evidence of increased disease resistance in longer‐term urbanized populations, as the result of natural selection. To test this,...
In a seasonal environment, there are multiple aspects of timing, or phenology, that contribute to an individual's fitness. Several studies have shown a genetic basis to variation between individuals in breeding time, but we know little about the heritability of other phenological traits in wild populations. Furthermore, the presence of genetic correlations between phenological variables could act...
Ongoing debate centers on whether certain types of mutations are fixed preferentially during adaptive evolution. Although there has been much discussion, no quantitative framework currently exists to test for these biases. Here, we describe a method for distinguishing between the two processes that likely account for biased rates of substitution: variation in mutation rates and variation in the probability...
C4 photosynthesis is a series of biochemical and structural modifications to C3 photosynthesis that has evolved numerous times in flowering plants, despite requiring modification of up to hundreds of genes. To study the origin of C4 photosynthesis, we reconstructed and dated the phylogeny of Molluginaceae, and identified C4 taxa in the family. Two C4 species, and three clades with traits intermediate...
Molecular phylogenies contribute to the study of the patterns and processes of macroevolution even though past events (fossils) are not recorded in these data. In this article, I consider the general time‐dependent birth–death model to fit any model of temporal variation in speciation and extinction to phylogenies. I establish formulae to compute the expected cumulative distribution function of branching...
Between‐individual variance in potential reproductive rate theoretically creates a load in reproducing populations by driving sexual selection of male traits for winning competitions, and female traits for resisting the costs of multiple mating. Here, using replicated experimental evolution under divergent operational sex ratios (OSR, 9:1 or 1:6 ♀:♂) we empirically identified the parallel reproductive...
We tested the hypothesis that forest and prairie populations of the gall‐inducing fly, Eurosta solidaginis, have diverged in response to variation in selection by its host plant Solidago altissima, and its natural enemies. A reciprocal cross infection design experiment demonstrated that fly populations from the prairie and forest biomes had higher survival on local biome plants compared to foreign...
The evolution of sexual dimorphism depends in part on the additive genetic variance–covariance matrices within females, within males, and across the sexes. We investigated quantitative genetics of floral biomass allocation in females and hermaphrodites of gynodioecious Schiedea adamantis (Caryophyllaceae). The G‐matrices within females (Gf), within hermaphrodites (Gm), and between sexes (B) were compared...
Understanding the factors that promote or inhibit species formation remains a central focus in evolutionary biology. It has been difficult to make generalities about the process of ecological speciation in particular given that each example is somewhat idiosyncratic. Here we use a case study of replicated ecological speciation in the same selective environment to assess factors that account for similarities...
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