Entomopathogen infection alters feeding behavior in the southern green stinkbug, Nezara viridula.

BRUNO E. ROSSO; MEDINA, VIRGINIA; SORIA, MARCELO; ZAVALA J. A

Conferencia; Animal Behaviour Live: Annual Online Conference 2020; 2020

Nezara viridula is a major pest of soybean crop with important economic losses. The stinkbug can tolerate soybean plant defenses as protease inhibitors and isoflavonoids. While gut bacteria can help some insects to overcome plant defenses, some plant allelochemicals may help insects to overcome entomopathogen infection. Although most of adults of N. viridula collected from soybean crops are free of cultivable bacteria, around 30% of the population have quite simple gut bacterial community, with less than 8 species. Moreover, the entomopathogen Serratia marcescens has been found in the gut of some individuals. We proposed that gut bacteria affect feeding behavior of N. viridula, modifying plant species preference of feeding. On summer, N. viridula adults can be found feeding on crops of soybean or corn, or on another weeds, as the glyphosate resistant Amaranthus quitensis. To evaluate the effects of entomopathogen infection on insect feeding behavior, we performed a 7-day multiple-choice field experiment where 20 non-infected and 20 Serratia sp. lab-infected stinkbug adults were challenged to feed on soybean or secondary hosts (corn, A.quitensis or spontaneous grown weeds), inside 3x3 mt gazebo (n=4). We found interactions between Serratia sp. infection and N. viridula host preference (p=0.001). While Serratia sp. infected stinkbugs preferred to feed on soybean, non-infected stinkbugs preferred feeding on secondary hosts. Moreover, Serratia sp. infected stinkbugs were seen switching hosts, while non infected-stinkbugs remained in their first choice of host. Here we demonstrate that entomopathogen infection changes feeding behavior of Nezara viridula adults, maybe due to the necessity to eliminate the bacteria through ingestion of antimicrobial compounds or changes in C/N ingestion, as a self-medication behavior.