Kairomone-induced changes in foraging activity of the larval ectoparasitoid Holepyris sylvanidis are linked with an increased number of male parasitoid offspring

Interactions between stored product pest insects and their parasitoids are well known to be mediated by infochemicals. However, little knowledge is available about the extent which parasitoid responses host kairomones improve search parasitization success. Here, we tested whether release of host-specific confused flour beetle, Tribolium confusum , improves finding larval ectoparasitoid Holepyris sylvanidis . Previous studies revealed that volatiles from feces [i.e., ( E )-2-nonenal 1-pentadecene] attract parasitoid. To determine most attractive concentration these two key components, conduced Y-tube olfactometer bioassays. Most female were attracted a mixture 1-pentadecene at lowest concentration, while highest was repellent. Volatiles adults (methyl- p -benzoquinone 4,8-dimethyldecanal) did not females any concentrations tested. In flight cage experiments, analyzed success H. offering larvae in Petri dish for 3 days (i) with additionally applied (test) or (ii) without additional (control). test cages, removed significantly higher number paralyzed initial population within 48 h than control cages. After 72 h, more parasitized cages control. The offspring differed one total numbers especially males. Significantly emerged enhanced male offspring. Our study demonstrates parasitoid’s response host-associated can but also affects males parasitoids’ progeny.