D3360: Description of the unique defensive behaviors of the radiant sun beetle Prionotheca coronata (Tenebrionidae)

We describe the unique anti-predator defenses of this species using 50 individual beetles that were captured in pit traps the night before their behavior trials. This species possesses sharp spines along the margin of their abdomen, and along the inner edge of their rear legs. When it is disturbed, it often assumes a head-down posture, with its rear legs spread open. 84% of beetles assumed this defensive posture immediately after being removed from the pit traps and prodded. Beetles often quickly rotate themselves in this posture to the left or right if the sand on either side of it is disturbed, but generally will not rotate if the sand directly behind it is disturbed. Beetles rotated left or right 58% of the time if the sand was touched to the left or right, but only 2% of the time if it was touched directly behind the beetle. If its rear legs and abdomen are touched simultaneously between them, it will often pinch your finger between the spines of its abdomen and rear legs, with a surprising amount of force. This pinching behavior occurred 78% of the time when the abdomen and rear legs were touched simultaneously, but occurred less frequently (31% of the time) if it was touched elsewhere (top, bottom and sides of the abdomen) without touching the legs. This pinching defense can draw blood in some cases. A link to a video documenting these behaviors is: https://www.youtube.com/watch?v=TxSS9UAHOOU .