Meeting Abstract
Plant trichomes (sharp microscopic hairs) on leaves from bean plants pierce and entrap insect pests. Coincidentally, although bed bugs (Cimex lectularius L.) are not naturally found in association with bean plants, they are also pierced and entrapped by these trichomes. The trichomes pierce the cuticle of the bed bug tarsi as the bugs walk on the leaves. The mechanical properties of bed bug tarsi were investigated in order to evaluate their vulnerability to piercing. This information will help inform development of physical methods for control of insect pests such as bed bugs. In order to interpret the forces measured during nanoindentation of cuticle at different locations on the bed bug tarsi, scanning electron microscopy was used to visualize the process of indent formation while poking the cuticle with a nanomanipulator on live, restrained bed bugs. Focused ion beam milling (with gallium ions) was used to selectively remove cuticle from different parts of the tarsi to visualize the complex way in which cuticle varied in thickness for different regions including the pretarsal claws. Cuticle of the tarsal subsegments showed permanent (plastic) deformation for small indentation depths of only 1 micron, while the area of the pretarsal claws that is usually pierced (the “membrane with microtrichia”) showed no plastic deformation until a minimum indentation depth of 8 microns was reached. Therefore, the areas of the tarsi that differ in vulnerability to piercing also differ in mechanical properties and behavior.
