Publications by authors named "Jae Chun Choe"

Eggshell bacterial communities may affect hatching success and nestling's condition. Nest materials are in direct contact with the eggshells, but the relationships with the eggshell microbiome during incubation have not been fully elucidated. Here, we characterize eggshell and nest material bacterial communities and their changes during incubation in the Oriental Tit (Parus minor).

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Many eusocial insects, including ants, show complex colony structures, distributions, and reproductive strategies. In the ant Wheeler (Hymenoptera: Myrmicinae), queens and males are produced clonally, while sterile workers arise sexually, unlike other ant species and Hymenopteran insects in general. Furthermore, there is a wing length polymorphism in the queen caste.

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Cortisol is a well-known endogenous glucocorticoid that serves as a stress indicator. It is normally released under stressful condition to warn about imminent danger and thus is critical for survival of the species. However, it is unclear how cortisol relates to cognitive process under physiological condition in high-order primates such as non-human primates (NHP).

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Urban environments present novel and challenging habitats to wildlife. In addition to well-known difference in abiotic factors between rural and urban environments, the biotic environment, including microbial fauna, may also differ significantly. In this study, we aimed to compare the change in microbial abundance on eggshells during incubation between urban and rural populations of a passerine bird, the Eurasian Magpie (Pica pica), and examine the consequences of any differences in microbial abundances in terms of hatching success and nestling survival.

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Humans are thought to be unique in their ability to help others voluntarily even though it may sometimes incur substantial costs. However, there are a growing number of studies showing that prosocial behaviors can be observed, not only in humans, but also among nonhuman primates that live in complex social groups. Prosociality has often been described as a major factor that facilitates group living.

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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 elucidate the effect of incubation on the bacterial abundance and bacterial community composition on the eggshells of the Eurasian Magpie (Pica pica). We found that total bacterial abundance increased and diversity decreased on incubated eggs while there were no changes on non-incubated eggs.

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Many animal species form communal roosts in which they aggregate and sleep together. Several benefits of communal roost have been suggested, but due to lack of data on relatedness among group members, it is unknown whether these benefits can be amplified by the formation of kin-based communal roosts. We investigate the genetic composition of two winter roosts of Eurasian Magpies (Pica pica), using microsatellite markers on non-invasive samples.

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Historical geological events and climatic changes are believed to have played important roles in shaping the current distribution of species. However, sympatric species may have responded in different ways to such climatic fluctuations. Here we compared genetic structures of two corvid species, the Azure-winged Magpie Cyanopica cyanus and the Eurasian Magpie Pica pica, both widespread but with different habitat dependence and some aspects of breeding behavior.

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Rhinopithecus roxellana are generally seasonal breeders, although copulation can occur throughout the year. Previous studies suggest that estradiol modulates female sexual behavior during the mating season. However, the effects of social context on estrogen levels and behavior have not been fully explored.

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Background: A female preference for intense sexual visual signals is widespread in animals. Although the preferences for a signal per se and for the intensity of the signal were often regarded to have the identical origin, no study has demonstrated if this is true. It was suggested that the female fiddler crabs prefer males with courtship structures because of direct benefit to escape predation.

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We evaluated whether cytochrome c oxidase subunit I (COI) barcodes that have been previously suggested for birds are useful for identifying species of the genus Larus, which are resident or migratory birds in Korea. We found 31 intra- or interspecific COI haplotypes from 12 of 13 Larus species in Korea. Haplotype analyses showed that the COI barcodes could not distinguish some interspecific haplotypes from 6 of 12 Larus species because there were no nucleotide substitutions among their COI haplotypes.

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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 had accessed their nests.

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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 isolation between sympatric populations. Thus, the direction of change in reproductive characters may be arbitrary in relation to changes in other morphological characters.

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A growing body of evidence suggests that the costs and benefits involved in cleaning interactions can vary over space and time depending on the environmental conditions. However, whether the same cleaners actually induce variable net outcomes in terms of host fitness remains unclear to date. Branchiobdellid annelids are generally regarded as commensals or rarely parasites of their freshwater crayfish hosts, but a recent study suggests that they may also function as cleaning organisms.

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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 the opposite sex rather than the same sex. Observing 53 foals between April and October 1998, we recorded 113 mutual grooming events.

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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 that pre- or postnatal stress impaired learning and memory performance of rats.

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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 demonstrates that, contrary to former expectations, the ecological and genetic conditions favoring caste differentiation are far more restrictive than those favoring high skew. Caste differentiation cannot be selected in saturated, symmetrical relatedness groups unless the genetic relatedness among group members is extremely high.

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Korean populations of the genus Cryptocercus occur in forested mountains throughout South Korea. They live in monogamous associations in which parents care for their young in complex woody galleries. Single paired adults (23.

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