Functional response of the assassin bug, Zelus tetracanthus, on larger tamarisk beetle Diorhabda carinata

The larger tamarisk beetle, Diorhabda carinata, was introduced into the western US as a classical biological control agent of invasive tamarisk. In the last several years, these beetles have crossed into Oklahoma. From previous surveys in tamarisk, it is likely that they will encounter the assassin bug Zelus tetracanthus. Previous laboratory studies have shown that the older nymphal stages and adults of Z.tetracanthus are capable of feeding on larval D. carinata. To further assess their potential predation rates on colonizing beetle populations, I performed a laboratory experiment assessing their functional response at increasing prey densities. I used the first and last nymphal stage as well as the adults of the predatory bug, and provided them first instar larval beetles at either 4, 6, 8, 12, or 16.