Spinosyns Cause Aedeagus Eversion in Carpophilus spp. (Coleoptera: Nitidulidae)

During an assessment of various insecticides against sap beetles, Carpophilus sp., it was noted that at least some males everted their reproductive structures (referred to as aedeagus from here forward) when treated with a spinosyn insecticide, spinetoram. This response to spinosyns or other insecticides is not documented in the literature even though sap beetles have been included in numerous insecticide assays and spinosyn insecticides have been in widespread commercial use for >20 yr. Additionally, other insect species have not been documented to show a similar aedeagus eversion response to spinosyns or other insecticides. The objective of this study was to further examine eversion of the aedeagus when sap beetles were exposed to different rates of two spinosyn insecticides, spinetoram and spinosad. Additionally, we examined whether a similar response would occur in other insects when three species of Coccinellidae (Coleoptera) and one species of Curculionidae (Coleoptera) were exposed to spinetoram. Our results show that male sap beetles respond to both spinosyns by everting the aedeagus, females did not have an analogous response. No similar response was observed for the assayed species of Coccinellidae or Curculionidae.