Defensive behaviour in Ghanaian praying mantids

The defensive behaviour of 25 species of praying mantids from Ghana is described. All have camouflage as the primary defence mechanism, either a general resemblance to vegetation, or a specific resemblance to bark, sticks, leaves or grass. Secondary defence mechanisms include running, flying, thanatosis, secretion of fluid from the mouth, startle display and flash colouration. The early instars of several species are ant-mimics. The female Taracbodes afzelii often guards her ootheca and also the young nymphs, and she can distinguish her nymphs from intruding ants which are attacked. Some mantids have a green/brown polymorphism and there is evidence that the frequencies of the two forms vary seasonally. Other mantids are stick, grass or bark mimics, and the possible ways in which the adaptations of these forms have evolved are outlined. The startle display is probably a bluff which protects the mantid to some extent from avian predators. It does not appear to be directed against predaceous mammals. A curious “boxing display” is described from Oxypilus, Anasigerpes and Catasigerpes. It probably functions to space out individuals, not to discourage attacks from predators. The occurrence of this display is used as taxonomic evidence for the close relationship of these three genera.