Learning can be detrimental for a parasitic wasp: R scripts and Telenomus podisi data

<p>Animals have evolved the capacity to learn, and the conventional view is that learning allows individuals to improve foraging decisions. We describe a first case of maladaptive learning where a parasitoid learns to associate chemical cues from an unsuitable host, thereby re-enforcing a reproductive cul-de-sac (evolutionary trap). <i>Telenomus podisi</i> parasitizes eggs of the exotic stink bug <i>Halyomorpha halys</i> at the same rate as eggs of its coevolved host, <i>Podisus maculiventris</i>, but the parasitoid cannot complete its development in the exotic species. We hypothesized that <i>T. podisi </i>learns to exploit cues from this non-coevolved species, thereby increasing unsuccessful parasitism rates. We conducted bioassays to compare the responses of naïve <i>vs</i>. experienced parasitoids on chemical footprints left by one of the two host species. Both naïve and experienced females showed a higher response to footprints of <i>P. maculiventris</i> than of <i>H. halys</i>. Furthermore, parasitoids that gained an experience on <i>H. halys</i> significantly increased their residence time within the arena and the frequency of re-encounter with the area contaminated by chemical cues. Maladaptive learning in the <i>T. podisi</i> - <i>H. halys</i> association is expected to further decrease parasitoid reproductive success and have consequences for population dynamics of sympatric native and exotic host species.</p>