Influence of the harborages in increasing of German cockroach, Blattella germanica, in laboratory condition

Abstract

The harborage material and the void number of the harborages influenced increasing in German cockroach population in a laboratory condition. In case of the harborage free the cockroach numbers were rather small compared with the existence of the harborages. The cockroach numbers increased notably with the harborages made of plywood, ceramic tile or plastic, and less numbers in metallic one. The void numbers were also related to increasing in the cockroach population. The initial numbers of three pair of the cockroaches increased up to 780 in total after three months with 5 void plywood harborages, whereas a similarly reared colony without any harborage attained only 94 individuals. In three months after, the young stage of nymphs was the majority in each condition. The results suggest that cockroach populations can recover quickly after incomplete control in case of abundant of cracks and crevices.