Impact of Latitude on Sexual Size Dimorphism in Ground Beetle Poecilus Cupreus L

Sexual dimorphism is a common phenomenon in insects, and it may be expressed in various traits including body size and body shape. Sexual selection is the main factor shaping such differences between males and females in insects, even if they depend also on food availability during larval stages. Body size can differ geographically between particular populations of one animal species, both with latitude and altitude, and it was undoubtedly shown for ground beetles. The latter are considered excellentbioindicators and model organisms for evolutionary studies. We have investigated ground beetle Pocilus cupreus body size variation practically throughout its entire range and have found that the curve of its body size variation was saw-tooth in latitude gradient and in longitude as well. Using that base set we estimates sexual size dimorphism (SSD) variation in geographical gradients.We have measured more than 8000 specimen of males and females in ground beetle Poecilus cupreus L. sampled in 14 large regions of Eurasia. Sexual Size Dimorphism changed drastically in latitude gradient not showing any trend to decrease or to increase. We conclude that several dominating factors affected SSD presentation in species studied, among which climatic factors at the sites where beetles have been sampled.