Meeting Abstract
Insects associated with plants have had hundreds of millions of years to coevolve against plant defenses. Non-chemical (physically-based) plant defenses include both sticky exudates and non-sticky entrapping microstructures on the plant surface. Biomimetic entrapment technologies have been used as non-chemical methods of insect pest control, and vary in their effectiveness against different target pest species. For example, sticky traps are not considered particularly effective in bed bug control efforts, in part because bed bugs are reluctant to walk on these surfaces and will avoid them. In order to quantify this reluctance, individual bed bugs were placed in arenas, surrounded by a border of sticky surface or a non-sticky but entrapping surface for comparison (fresh leaves from bean plants, which are known to entrap bed bugs). We quantified how many times a bed bug would touch a surface with its tarsi and back off before taking more steps on the surface, and how many steps a bed bug would take before getting stuck on a surface. We did these assays with both a single choice for material and two-choice tests. We found that in the absence of choice, an individual bed bug would usually end up getting stuck on any of the surfaces within the 5-minute evaluation time window. We found that bed bugs given a choice, usually backed off from the sticky material, but not from the fresh bean leaves, and therefore usually got entrapped on the bean leaves regardless of which surface was encountered first. These results suggest that a non-sticky entrapment material is more likely to be effective in insect entrapment than a sticky material that generates an avoidance response from the bed bug.
