Behavioral responses of the egg parasitoid Anastatus orientalis (Hymenoptera: Eupelmidae) towards adult ‘footprints’ of target and non-target hosts

The spotted lanternfly, Lycorma delicatula, is native to eastern Asia and is now an invasive agricultural pest in the U.S. The egg parasitoid Anastatus orientalis, which is native to Asia, is a candidate biological control agent of L. delicatula. As part of candidate suitability evaluations, we investigated the parasitoid’s behavioral responses to chemical traces (‘footprints’) deposited by its target, L. delicatula, and by two potential non-target host species, Poblicia fuliginosa (a North American native lanternfly species) and Halyomorpha halys (an invasive stinkbug species from eastern Asia). Motion tracking software (EthoVision) was employed to record and analyze the behaviors of A. orientalis on non-target and target host-marked and control substrates. Wasps exhibited a ‘motivated searching’ behavior (i.e., longer residence time, slower walking velocity, and coverage of greater distances) when in contact with traces originating from females of the target pest compared to blank controls. However, this searching behavior was not significantly different than controls when exposed to footprints of the non-target hosts. These results are discussed in the context of host preference and risk in importation biological control.