Stick insects or phasmids (Phasmatodea) and praying mantises or mantids (Mantodea) both belong to a taxonomic construct called “Orthopteroidea”, with albeit uncertain affiliations. In both groups, females are much larger then males. In mantids, this sexual dimorphism can even lead to the smaller male being consumed by the voracious female during mating. Whereas mantids feed on other insects, phasmids are herbivorous.
Phasmids usually mimic dead twigs, but can fight off predators by either scent, making noise or flashing bright colours when opening their wings. Most readily seen, especially on the underside of leaves of their favourite food plant, Harungana madagascariensis, is Leiophasma nigrotuberculatum.
Mantids usually mimic green leaves or flowers. Unlike stick insects, they don’t primarily use their camouflage to escape predators, but to lie in wait and ambushing their own prey. The most common species in Andasibe is Polyspilota aeruginosa. Interestingly, praying mantises (as well as other orthopterans) appear to be often infested with nematode horsehair worms.
Two French entomologists, Nicolas Cliquennois and Bruno Mériguet, have repeatedly collaborated with Mitsinjo, which has helped establish a preliminary list of the species occurring in Andasibe for both groups.
After several inventories over a couple of years, Nicolas Cliquennois, notorious (and dreaded by Mitsinjo staff) for extending his nightwalks in the search of stick insects until just before sunrise, has tirelessly produced a list of about 25 species of stick insects occurring in Andasibe’s forests. The botanical expertise of Youssouf has helped to identify the favourite foodplants of each of the species detected.
A renowned mantid specialist of the Office pour les Insectes et leur Environnement (OPIE), Bruno Mériguet has focused on the praying mantises of Andasibe. His data have been completed by German entomologist Kai Schütte of the University and Zoological Museum Hamburg.