The effects of habitat, density, gender and duration on overwintering success in Bembidion lampros (Coleoptera: Carabidae)

Abstract

AbstractIn temperate climates, winter mortality is a key factor influencing insect survival. In Bembidion lampros (Coleoptera: Carabidae), an abundant polyphagous predator in arable farmland, we investigated how habitat, population density, gender and duration of overwintering affect the winter mortality and body condition of survivors. In a field experiment, we introduced beetles at two population densities into isolators placed either in the interior of the field or in the grassy boundary. Half of the isolators were collected in mid‐March, and the remaining half were collected in mid‐April. Across all treatments, 44–92% of the beetles survived until spring. Survival was significantly higher in the field interior than in the boundary. The longevity of individuals starved after overwintering was higher in females than in males and was positively related to the length of time spent at the overwintering site. Population density was positively related to percentage survival but did not affect body condition. Our results suggest that biotic factors such as population density and predation, though little studied, may have a similar significance as abiotic factors. Even ubiquitous carabid species inhabiting agroecosystems have specific requirements for overwintering. Understanding these requirements is useful for developing techniques to support their overwintering success.