Morphological variability of Bembidion aspericolle (Coleoptera, Carabidae) populations in conditions of anthropogenic impact

Abstract

Bembidion (Talanes) aspericolle (Germar, 1829) is a Western Palearctic species which lives on the shores of the Atlantic Ocean, the Mediterranean, Black and Caspian Seas and saline inland habitats from Central Europe to Central Asia. Anthropogenic impact is one of the most important environmental factors affecting the morphological variability of ground beetles. The objective of our research is assessment of the morphological variability of this species in three ecosystems differing by intensity of anthropogenic impact. 13 linear characteristics, one angular characteristic, density of pores on the prothorax and elytra, contrast of spots on the beetles’ elytra were measured, and 6 morphometric indices were calculated. The mean value of body length in females is more than in males in the studied populations. In the ecosystem with high anthropogenic pressure, female body length is shorter by 3.7% and elytra length is shorter by 6.0% than in females in the ecosystem with low anthropogenic impact. Differences between populations in the body length of males are not significant. In the ecosystem with high anthropogenic transformation, sexual dimorphism is observed only on head and prothorax width. The ratio of maximum width of elytra to maximum prothorax width decreases significantly with increasing anthropogenic load. The impact of anthropogenic factors on the ecosystem produces significant changes in elytra length and head width of B. aspericolle and in four of the six morphometric indices. It is reasonable to use these morphometric characteristics of B. aspericolle adults in bioindication. The complex of anthropogenic factors does not have a significant impact on the value of anterior and posterior angles of prothorax, density of prothorax and elytra puncturing and contrast of the light spots at the top of the elytra. The sex of the specimen influences all linear characteristics. The absence of significant differences in morphometric indices between males and females shows that the body proportions of the beetles remain unchanged and only linear dimensions vary. Research on the morphological variability of B. aspericolle is important for understanding microevolutionary processes in populations of beetles under anthropogenically induced changes in the environment.