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BACKGROUND In ecological character displacement, traits involved in reproductive isolation may not evolve in arbitrary directions when changes in these traits are by-products of adaptation to an ecological niche. In reproductive character displacement, however, selection acts directly on reproductive characters to enhance the degree of reproductive(More)
The ability to distinguish among heterospecific individuals has been reported in only a few animal species. Humans can be viewed as a special type of heterospecifics because individuals differ widely in behavior, ranging from non-threatening to very threatening toward animals. In this study, we asked whether wild magpies can recognize individual humans who(More)
When females search for mates and their perceived risk of predation increases, they less often express preferences for males that use conspicuous courtship signals, relaxing sexual selection on production of these signals. Here, we report an apparent exception to this general pattern. Courting male fiddler crabs Uca beebei sometimes build pillars of mud at(More)
We investigated the phylogenetic relationships of species and subspecies of the cosmopolitan genus Pica using 813 bp of the mitochondrial genome (including portions of 16s rDNA, tRNA-Leu, and ND1). The phylogenetic relationships within the genus Pica revealed in our molecular analyses can be summarized as follows: (1). the Korean magpie (Pica pica sericea)(More)
Many environmental factors during the pre- or postnatal period can affect an individual's cognitive function and neural development throughout life. Little is known, however, about the combined effects of the pre- and postnatal environments on cognitive function of adult offspring and structural alterations in the adult brain. In this study, we confirmed(More)
These authors contributed equally to this study. ABSTRACT Many environmental factors during the pre-or postnatal period can affect an individual's cognitive function and neural development throughout life. Little is known, however, about the combined effects of the pre-and postnatal environments on cognitive function of adult offspring and structural(More)
We investigated mutual grooming by Jeju pony (Equus caballus) foals to determine whether male foals preferentially interact with potential future sexual partners or competitors. We predicted that relative to female foals, male foals would exchange grooming more frequently with young mares and that in general, foals would mutually groom more frequently with(More)
Predation is generally thought to constrain sexual selection by female choice and limit the evolution of conspicuous sexual signals. Under high predation risk, females usually become less choosy, because they reduce their exposure to their predators by reducing the extent of their mate searching. However, predation need not weaken sexual selection if, under(More)
Inhibitory effect of incubation on microbial growth has extensively been studied in wild bird populations using culture-based methods and conflicting results exist on whether incubation selectively affects the growth of microbes on the egg surface. In this study, we employed culture-independent methods, quantitative PCR and 16S rRNA gene pyrosequencing, to(More)
Reproductive skew theory has not heretofore formally addressed one of the most important questions in evolutionary biology: How can whole-life sterile castes evolve? We construct a transactional skew model investigating under what conditions a subordinate in a multimember group is favored to develop into a morphologically specialized worker caste. Our model(More)