Male Physadesmia globosa beetles spend much of their active time following females, searching for single females, or contesting with other males for position behind females. Once paired with a female, a male does not feed, can seldom stay paired for more than a few min, and can mate only if the female stops moving. Females rarely stop moving unless they find a large food item, or burrow into the sand and become inactive. Thus, males expend great effort positioning themselves for opportunities to mate, which seldom arise. However, males do not display any alternative mating strategies, and none appear to be available, for females are scarce in relation to males, and do not become receptive to mating at any predictable times or places. Keywords: Namibia, Namib Desert, Kuiseb River, desert beetles, tenebrionid beetles, reproduction, insect behaviour, mate guarding, sexual selection, reproductive behaviour, mating behaviour.