The biology of four sympatric Poecilus species

Abstract

During a intensive investigation of the epigeal fauna of a 22 ha winter rye field in Berlin, large numbers of four Poecilus species were caught dur- ing the years 1984-1986 by pitfall traps, time- sorting pitfall traps and window traps. These four species, Poecilus lepidus, P. cup reus , P. versic- olor and P. punctulatus represented more than 53% (n = 13588) of all Carabidae caught in the pitfall traps. The most abundant species, P. lep- idus, represented 39.9% (n = 10224) of all ground beetles. Spatial distribution showed a clear separation of these four species within the field, which cannot be explained by their known ecological requirements. Furthermore phenol- ogy, hibernating behaviour, diurnal activity, dry weights and flight activity were compared. Rear- ing experiments in the laboratory yielded further information on larval development.