Reproduction strategies in promiscuous ladybird beetles.

Ladybird beetles (Coleoptera: Coccinellidae) mate often and change many partners during their lives. We were interested how many males really contributed to the progeny of a single female of the invasive ladybird species, Harmonia axyridis. We investigated whether frequency of mating and paternity varied according to the colour form of the male in this polymorphic species, according to the order of mating in a controlled laboratory experiment, and with the male body size. We let a female to mate sequentially with two or three males of different colour morphs. We were then able to score the father of each individual of the next generation according to the colour of elytra. In the field, we counted number of males and females, single and copulating, of diverse colour morphs.

Melanic individuals mated somewhat more often than light individuals. Microsatellite analysis revealed that progeny of a single female from the field was sired by more than five males in average. Colour forms differed in their paternity success. First male had advantage over the later males. Larger males had more progeny than small ones. However, females in the field mated with males regardless of size.