Ecology and behavior of the desert burrowing cockroach,Arenivaga sp. (Dictyoptera, Polyphagidae)

Measurements were made of environmental conditions in the microhabitat ofArenivaga sp., and results were correlated with their diurnal migratory behavior. The animals live in sand dunes with less than 1% moisture most of the year. During the day in spring, summer and fall they borrow in the sand at a depth of 20-60 cm, while at night, when surface temperatures have cooled, they borrow within 1-3 cm of the surface. In winter they are rarely found near the surface, remaining active at lower levels during both night and day. Adult males were collected on the surface or at a depth of 20-60 cm, but they were never observed burrowing near the surface at 1-3 cm.The larvae and adult females are photonegative and remain at lower levels during the day, even though daytime temperature and humidity are sometimes favorable near the surface. In the summer, they migrate to the surface about 2 h later after darkness than in spring and fall. Temperature measurements indicated this was probably due to delayed nighttime cooling of the surface in the summer months. By burrowing near the surface the animals can experience cooler nighttime temperatures and water-loss may be reduced during the summer. This behavior may also facilitate disperasal and mating.The cockroaches feed on decaying leaves and the roots of desert shrubs. Since the latter have 35-38% moisture, they are probably the main source of water for these animals.