Common Spiny Flower Mantis

The adult has spiny structures on the underside of its abdomen, giving it its name. It is variable in colour, being typically light green, but it can equally be tinted yellow, pink, or red. It has a large eyespot on its forewings, which is black, green and cream and is surrounded by a green patch. The inner hind wings are orange and the outer hind wings are transparent. Nymphs are black until the third instar.

Sexual dimorphism. P. wahlbergi exhibits sexual dimorphism. Females have small spines towards the base of their wings and six to seven segments on their abdomen. Females also tend to have slightly shorter antennae, longer wings, and take seven moults to reach maturity. On the other hand, males lack the spines found near females' wings, have eight abdominal segments, shorter wings, longer antennae and require six moults to reach maturity.

P. wahlbergi has a deimatic display in which it spreads its forewings, making itself appear larger and prominently displaying its eyespots to startle would-be predators. While at rest it is well camouflaged, and is a sufficiently good aggressive mimic of a flower that prey insects can attempt to pollinate it, at which moment the mantis seizes and eats them. They prefer to prey on flying insects and spiders, but if unavailable, will eat virtually any insect. Like with many mantis species, P. wahlbergi females practice sexual cannibalism; however, nymphs are not cannibalistic until their fourth instar.