Evidence for direct oviposition into substrates by the New Zealand stick insect Spinotectarchus acornutus

Stick insects (Phasmatodea) have many different oviposition strategies, reflecting a range of adaptive behaviours and morphologies to best place and secure eggs in their environments. Oviposition strategies in Aotearoa New Zealand phasmids are not well documented, but the literature so far suggests that they drop individual eggs to the ground from their position in the foliage. Here, we present evidence for an oviposition strategy unique among the Ro stick insects of Aotearoa New Zealand. Individual female Spinotectarchus acornutus were observed inserting their eggs in a range of substrates, in particular the bark of trees and in spaces within the textured surfaces of tree fern trunks. We also highlight how the specific morphology of their eggs may be an adaptation to assist in substrate attachment, while their elongated secondary ovipositor could aid in egg insertion into substrates.

Automated summary

This article presents the oviposition strategies of stick insects in New Zealand. It suggests that phasmids in New Zealand drop individual eggs from their position in the foliage. In addition, a unique oviposition strategy of the Ro stick insects, Spinotectarchus acornutus, is highlighted, where the female insects insert their eggs into substrates like tree bark and textured surfaces of tree fern trunks. The study also emphasizes the morphological adaptations of their eggs and elongated secondary ovipositor.