Introgression and Habitat Segregation in a Pair of Ladybird Beetle Species in the Genus Propylea (Coccinellidae, Coccinellinae) in Northern Japan.

The ladybird beetles Propylea quatuordecimpunctata and P. japonica have largely overlapping distributions in northern Japan, and in the laboratory produce fertile hybrids. In this study, we surveyed the distribution and morphological differentiation of these species and the hybrids in natural populations, with a focus on western Hokkaido, northern Japan.

Phylogeny of epilachna, henosepilachna, and some minor genera of phytophagous ladybird beetles (coleoptera: coccinellidae: coccinellinae: epilachnini), with an analysis of ancestral biogeography and host-plant utilization.

Ladybird beetles in the tribe Epilachnini include notorious crop pests and model species studied intensively in various fields of evolutionary biology. From a combined dataset of mitochondrial (ND2) and nuclear (28S) DNA sequences, we reconstructed the phylogeny of 46 species of Epilachnini from Asia, Africa, America, and the Australian region: 16 species in Epilachna, 24 species in Henosepilachna, and one species each in Adira, Afidenta, Afidentula, Afissula, Chnootriba, and Epiverta. In our phylogenetic trees, both Epilachna and Henosepilachna were reciprocally polyphyletic.

Contribution of multiple isolating barriers to reproductive isolation between a pair of phytophagous ladybird beetles.

Reproductive isolation between species may often be attained by multiple isolating barriers, but the components are rarely studied in animal taxa. To elucidate the nature of multiple isolating barriers, we quantified the strength of three premating barriers, including ecologically based ones (seasonal, habitat, and sexual), two postmating-prehatching barriers (reduced egg hatchability and conspecific sperm precedence [CSP]), and one posthatching barrier, including four components of F(1) hybrid reduced fitness, between two phytophagous ladybird beetles, Henosepilachna vigintioctomaculata and H. pustulosa.