Biology of Harmonia axyridis (Coleoptera: Coccinellidae) in Winter Aggregations

Abstract

Adults of the introduced coccinellid Harmonia axyridis (Pallas) were collected at aggregation sites in the autumn of 1993 and 1994 and described in terms of sex, size, and phenotype. Mating status and ovariole numbers of females and parasitism rates of both sexes were obtained by dissection. Females were larger than males, and beetles of both sexes from high elevations were larger and darker than their counterparts from lower elevations. In 1993, 11.8% of females had sperm in their spermathecae but 41.4% of females were mated in 1994. Adults were parasitized by Strongygaster triangulifera (Loew) (Tachinidae) at rates of 14.2 and 1.4% in 1993 and 1994, respectively.