Mobility and mating frequency in the scramble competition polygyny of a chrysomelid beetle

Abstract

In scramble competition polygyny, male and female mobility may be under strong selection as a result of fitness effects of searching for reproductive resources such as mates, oviposition sites, or resources for egg production. We analyzed the relationship between mating frequency, mobility, and body size in males and females of the chrysomelid beetle Leptinotarsa undecimlineata. We obtained a detailed data set of movement and mating frequency of an entire population (1037 adults) over a full reproductive season using individual tagging and direct behavioral observations. Unlike previous studies, we found a negative relationship between mobility and mating success for both sexes. Size was positively correlated to mating frequency in females, but negatively in males. High male mobility may be the result, and not a cause, of low mating success in scramble mating polygynies where rejected or displaced males switch plants more often searching for mating opportunities. More mobile females may be looking for competition-free oviposition substrate and thus experiencing fewer sexual encounters.