Rhinoceros beetles of the species Oryctes boas and O. monoceros were used in this investigation. Both species are large, weighing about 3*5 g and having a wing span of about 10 cm. There appears to be no difference in the flight motors of the two species. The beetles are common in sugar-cane fields and in well-established compost and manure heaps in Natal. The animals were kept in compost in me...