Aerial righting in wingless stick insects

First instar Extatosoma tiaratum, ~1.7 cm long.
Analysis of velocity vectors with respect to rotational aerodynamics.

Following my discovery of gliding behaviors of nymphal Extatosoma tiaratum stick insect at UW greenhouse in fall 2005, I conducted a series of researches on gliding behavior of nymphal stick insects as an undergrad. It was extended into my PhD thesis research, which addressed key issues in insect flight evolution by using the stick insects as a model system.

The newly published paper on Interface Focus studied how wingless nymphal stick insects perform mid-air righting through leg movements. A 2 cm-long stick insect baby can perform controlled mid-air righting with rapid rotations followed by a sudden deceleration, finishing reorientation within 0.3 seconds. This remarkable righting performance is achieved through leg movements interacting with local airflow, and by regulating leg-flow interactions asymmetrically.

A pop-science article explaining the details can be found here

(Left: Anand Varna; Right: Yu Zeng)