The effects of body size on mating and reproduction in Brachinus lateralis (Coleoptera: Carabidae)

Abstract

Abstract. 1. The causes and reproductive consequences of body size variation of Brachinus lateralis Dejean, a parasitic carabid beetle, were investigated. 2. Body size variation occurs within and between sites. Host size has a major influence on body size of the adult. 3. Fecundity is positively correlated with body size. Egg size is not correlated with body size. 4. Mating males tend to be larger than non‐mating males. There is a positive correlation of body sizes in mating pairs. 5. Limited opportunity for host choice may maintain size variation despite the advantages of large size. 6. The non‐random patterns of mating for a species without obvious intrasexual aggression suggest that subtle means of male‐male competition or female choice may be important.