Parastizopus armaticeps, a nocturnal detritivorous tenebrionid associated with itsmajor foodplant Lebeckia in the southern Kalahari, forms aggregations in burrows around this bush at all dune elevations. Both sexes migrate downslope after rain to breed, especially females from higher dune elevations, but not all beetles are reproductively active simultaneously. During drought, beetles inhabit deeper burrows located downslope in shaded areas and form larger groups. Mortality is highest during drought amongst beetles in shallow burrows. The importance of burrow selection for thermoregulation and associated evaporative water loss are discussed. Keywords: nocturnal tenebrionid, aggregation, reproductive success, burrow selection, thermoregulation; mortality.