Feeding-induced changes in resource quality and volatile pattern of green beans are associated with host preference in Halyomorpha halys

Abstract

The brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive, polyphagous pest insect with a broad host range of various cultivated plants, including several legumes such as green bean (Phaseolus vulgaris). The bugs feed on the bean pods and cause visible damages to the plant tissue. The feeding-induced chemical changes in fruits, including potential alterations in resource quality and volatile emissions, and their impact on insect’s behaviour, remain unclear. In this study, bush bean pods were used as a model system to investigate these effects after a three – day bug feeding period. Macronutrient analyses revealed a reduction in sugars and lipids after bug infestation, while protein content was not affected. Different sugars and sugar derivates, organic acids, and amino acids decreased due to the feeding activity. Furthermore, these nutrient changes were associated with significant quantitative and qualitative changes in the VOC profiles of infested beans. In addition, the bugs’ preference for the differently treated beans and for beans presented together with synthetic volatiles was assessed. The bugs showed a preference for uninfested beans over infested beans. The addition of β-cedrene, a compound that was induced by the feeding of H. halys, led to an avoidance of beans presented with this compound. These results suggest that feeding-induced changes in bean chemistry, including volatile emission may provide cues that enable insects to detect and avoid infested food sources. This study enhances our understanding of insect-plant interactions and host selection mechanisms in a polyphagous insect.