Comparison of the development time at different temperatures of two Aleochara species, predator and parasitoid of the cabbage root fly

Two staphylinids, Aleochara bilineata Gyll. and A. bipustulata L., predator of eggs and parasites of the cabbage root fly pupae (Delia radicum L.), ar e observed in natural conditions in same proportion. To understand how thes e two sympatrical species can coexist and to bring some new data about thei r biology, the two staphylinids are reared at different temperature of 5, 9 , 12, 17, 20, 24 et 35 degrees C in laboratory. Development time and mortal ity were analyzed. Penetration rate in pupae by larva is higher in A. bilin eata than in A. bipustulata. The latter seems well tolerate low temperature . Development of the two staphylinids is effective and homogeneous between 12 et 24 DC. Optimum of development would be 17 degrees C for A. bilineata and 24 OC for A. bipustulata.