A Kicking Butterfly Chrysalis

One of the primary characteristics of the pupal stage of most holometabolous insects is their immobility. This paper describes a previously unknown example of mobility in a pierid pupa from SE Asia. The movements of the pupae of Catopsilia pomona assume the form of a vigorous kicking motion when disturbed. Their sensitivity to touch was found to decrease with time since ecdysis, but detachment of the silk girdle was sufficient to solicit kicking in all pupae. Microscopic analysis indicated that the kicks are generated at the posterior of the abdomen by the retention of freedom of movement in two abdominal segments (A5 and A6). Video analysis suggests that the kicks are probably products of general cutaneous sensitivity rather than specialized sensilla and generate both ‘surprise’ and force by their extreme speed (<1s). The hypothesis that this is an anti-predator defense is supported by field observations and video of attempted predation by weaver ants (Oecophylla smaragdina) in which individual attackers boarding the pupae were shaken off and thrown to the ground.