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Cheilomenes sexmaculata (Coleoptera: Coccinellidae) is widely distributed from intermediate latitude to equatorial regions. Here, we examined its genetic structure and diversity based on a 627 bp region of the mitochondrial COI gene. We then estimated its demographic changes over the past 30 000 years. We observed 22 haplotypes in 339 individuals from 29 sites in Japan and Taiwan. The 22 haplotypes were integrated into two haplotype groups: one group exists at higher frequencies in lower latitudes (22-26°N), whereas the other group appears at higher frequencies in higher latitudes (30-37°N). The effective population size of the group that predominates in higher latitudes increased from 15 000 to 10 000 years before present. In contrast, the size of the lower-latitude group has remained constant for 30 000 years. These data suggest that C. sexmaculata might have expanded its distribution northwards and could be increasing its population size since the last glacial period. [ABSTRACT FROM AUTHOR]

Differences in the time of occurrence of both sexes of adult ladybirds, which reflect differences in the longevity and reproductive strategies of the sexes, is important from the perspective of applied entomology, including biological control, as well as basic entomology. Nevertheless, there is little field census data on this topic. We investigated the seasonal occurrence of both sexes of Cheilomenes sexmaculata (Fabricius) in Osaka City, central Japan, from 2003 to 2011. Female adults tended to appear earlier than males after hibernation or aestivation. That males never appeared earlier than females during the nine year period of this study indicate that protogyny occurs after hibernation and aestivation in this species. [ABSTRACT FROM AUTHOR]

The ladybird beetle, Cheilomenes sexmaculata (Fabricius), has been extending its distribution in and around urban areas at higher latitudes in Japan over the past 100 years. Between 2003 and 2011, we investigated the seasonal occurrence, aphid prey and population dynamics of this species in an urban park in Osaka City, central Japan. We found that C. sexmaculata completes three generations a year in Osaka. Overwintered adults emerge in March or April and produce two (or rarely one) generations by summer. Second-generation adults aestivate and subsequently produce another generation in autumn. This species feeds on five species of aphids that infest planted shrubs and alien weeds throughout the vegetative season. We analyzed the association between accumulated temperature and when overwintered adults first emerged. In addition, we determined the association between their time of emergence, peak abundance and last occurrence, and meteorological conditions. There was no association between the sum of effective temperatures and termination of adult overwintering. There was, however, an association between first occurrence and peak abundance, and climatic conditions, such as warm temperatures or low humidity. This species maintained a stable population in an urban park by becoming quiescent when climatic conditions were unfavourable or prey was scarce. We discussed these findings in relation to urban environmental factors, such as climate, food conditions and vegetation. [ABSTRACT FROM AUTHOR]