Patch dispersal and parasitism efficiency of the parasitoid Telenomus podisi are influenced by host abundance and release accuracy

Habitat quality is an important factor linked to decision-making in female parasitoids, whether related to the infestation patch quality or the availability of resources in the area. Host abundance, together with the spatial location of the infested patch, is known to be directly linked to the foraging time and parasitism efficiency of parasitoids. Within this context, this study aimed to investigate how host abundance affects patch residence time by Telenomus podisi (Hymenoptera: Scelionidae) and whether the accuracy of its spatial release in the field influences parasitism rates upon eggs of Euschistus heros (Hemiptera: Pentatomidae). Two separate experiments were conducted according to our objectives. The first, a microcosm experiment, evaluated the patch residence time in relation to host abundance. The second, a semi-field experiment, evaluated parasitism of E. heros eggs in relation to  parasitoid release accuracy. The dispersal time of T. podisi females from the microcosm study was significantly lower at high densities of E. heros eggs. In addition, event probability analyses further indicated that females are less likely to disperse at high host egg abundance when compared to low abundance. In addition, the location where the parasitoids were released in the field had a significant effect on the parasitism rate. T. podisi parasitized more E. heros eggs when the females were released more accurately on the infestation spot. Given these results, host abundance and release accuracy should be considered to optimize the augmentative biological control of E. heros in soybean fields.