Appunti di storia naturale sul coleottero ripicolo Carpelimus obesus (Kiesenwetter) (Staphylinidae Oxytelinae)

Abstract

SOME NOTES OF LIFE HISTORY ON THE LAKE SHORE DWELLING BEETLE, carpelimus obesus (KIESENWETTER) (STAPHYLINIDAE OXYTELINAE)

More than 200 adults of Carpelimus obesus were selected from plant debris on shores of the San Giuliano Lake in Matera (Basilicata, Southern Italy) and were fed in the laboratory. Here, females burrowed oviposition cells in the ground of vessels and released just 4 eggs at a time in every cell. After some 60 hours, eggs of single cells hatched at the same time, and 3 larval instars did follow. Larval development required about 25 days. Third instar larvae pupated into a hemielliptical cell, which they built by assembling small soil particles.

In the laboratory, both adults and larvae were observed to burrow tunnels, in the meantime they fed soil and released a remarkable amount of feces. Possibly, this behaviour does correspond to the feeding on the mud of the lake shore. So, masses of plant debris in the natural environment attract and recover beetles without directly providing them with food.

Author speculates about the factors impelling females to release a fixed number of egg in each cell; because neither the number of ovarioles nor vagina structure can explain this, he supposes a physiological regulation to be involved.

Key words: Carpelimus, laboratory observations, oviposition, feeding activity, anatomical features.