Interspecific interactions between egg parasitoids: foraging behavior of two egg parasitoids of the stink bug Piezodorus guildinii (Hemiptera: Pentatomidae)

CINGOLANI, M.F.; COLAZZA, S.; LILJESTHRÖM, G.G.; BARAKAT, M.C.

Perugia, Italia

Congreso; 6th INTERNATIONAL ENTOMOPHAGOUS INSECTS CONFERENCE; 2019

Universidad de Perugia

In the search for hosts, parasitoids may experience competition between adults exploiting the same host (extrinsic), or between larvae developing inside the host (intrinsic competition). An intrinsically inferior competitor may coexist with an intrinsically superior one, if it has better abilities to locate host. Adult parasitoids´ abilities to find, parasitize and defend hosts determine their resource´s retention potential. In soybean, two egg parasitoid species, Telenomus podisi and Trissolcus urichi (Hymenoptera: Platygastridae), compete on the egg masses of Piezodorus guildinii (Hemiptera: Pentatomidae) one of the major pest of this crop in Argentina. We evaluated parasitoid´s foraging abilities performing two different experiments: (1) we exposed parasitoids to chemical cues not directly associated with the presence of host eggs, and (2) we exposed parasitoids directly to a host egg mass. Both arena residence time and retention time were similar for T. podisi and T. urichi on male or female host footprints. In its turn, T. urichi reentered the area contaminated with P. guildinii more times and staid longer in it than T. podisi. Moreover, when parasitoids were exposed directly to host eggs, both species took the same amount of time to find and contact eggs, and to start parasitizing them. In the laboratory, both species exhibited similar abilities in locating hosts and manipulating, although there are many factors that can affect parasitoids behavior in field, and that cannot be adequately represented in the microcosm of laboratory experiments. Besides, both parasitoid species compared in this study are closely related, having very similar life history strategies. These could have covered up other aspects of the host foraging abilities of each species, which can make differences when searching for hosts in the field. This study provides information about the potential interspecific competition between these parasitoids, which contributes to evaluate the compatibility of multiple natural enemies? biological control programs for stink bugs.