Annual activity density of groundbeetles (Coleoptera: Carabidae) of a Celtis ehrenbergiana (Rosales: Celtidaceae) forest of Buenos Aires province, Argentina.

The aim of this study was to describe the annual activity cycle, the sex ratio, and the relationship between the weather variables and activity density of the 16 most abundant carabid species of a typical southeastern region of Pampasia, Argentina. The study focused on the southernmost Celtis ehrenbergiana (Klotzsch) Liebmann ( = C. tala Guillies ex Planch) native forest of the region, from March 2008 to March 2009, a period during which there was a marked draught associated with the La Niña phenomenon. Forty-five pitfall traps were emptied once every 2 wk, and the occurrence of larvae, tenerals, and subtenerals was recorded. Photoperiod, temperature, and precipitations explained 35% of the total variation in the catch. Total carabid activity was high in early autumn and late spring. Eight species reached their maximum activity in spring, five in winter, two in summer, and one in autumn. Possible reproductive strategies, the influence of different variables involved in the life cycles of the species, and the sex ratio and their limitations are discussed.