Investigation of interactions between a native and exotic egg parasitoid of brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae)

The current economic impact of the invasive, exotic brown marmorated stink bug (BMSB) is difficult to overstate. With its broad diet breadth and constantly expanding distribution, an integrated management approach is necessary for management of this pest. Biological control could provide long term, sustainable suppression and as such multiple native and exotic solitary egg parasitoids are currently under study as potential biological control agents. Native egg parasitoid species have contributed to 43.8% parasitism rates in ornamental nurseries. The USDA is currently conducting host range tests on the exotic egg parasitoids. However, no study has yet investigated the impact of interactions between exotic parasitoids likely to be released and native parasitoids already impacting BMSB populations in the field. Solitary egg parasitoids are more sensitive to the effects of competition as the resources within their host can only support the full development of one parasitoid. To observe their behavior and determine potential impacts, be they additive, antagonistic or synergistic, I exposed each parasitoid to a BMSB egg mass in absence of another species or with potential competition present. I developed a system of relevant behavioral modalities to quantify the observational data. These studies were conducted on the most prevalent native species found parasitizing BMSB in ornamental systems: Anastatus reduvii (Eupelmidae) and a non-native species likely to be released Trissolcus japonicus(Scelionidae). Recorded interactions and their potential impacts will be discussed.