Effect of shelter on reproduction, growth and longevity of the German cockroach, Blattella germanica (Dictyoptera: Blattellidae)

Abstract

German cockroaches spend most of the day in aggregations within shelters, which they leave in nocturnal foraging trips; cockroaches are rarely seen outside shelters during daylight hours. However, when population density exceeds shelter availability, diurnal aggregations form in exposed, unsheltered locations. To determine if shelter availability affects fitness of B. germanica, we reared cohorts of nymphs in laboratory arenas with or without shelters, and measured reproduction and longevity of tagged adults. When shelters were available in arenas, nymphs developed faster, adults gained more body mass, and females produced more fertile oothecae than when arenas lacked shelters. Therefore, shelter alone has a significant positive effect on growth and reproduction of B. germanica, and reducing or eliminating shelters should affect population growth of B. germanica in residential and industrial settings.

This project was supported in part by the National Research Initiative of the USDA National Institute of Food and Agriculture grant number 2004-35302-14880, the Risk Avoidance and Mitigation Program of the USDA-NIFA grant number 2005-51101-02388, the Blanton J. Whitmire endowment at North Carolina State University, and a scholarship from the North Carolina Pest Management Association.