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

Area of Science:

• Entomology
• Insecticide Toxicology
• Pest Management

Background:

• Spinosyn insecticides are widely used, yet specific insect responses can remain undocumented.
• Previous insecticide assays involving sap beetles (Carpophilus sp.) have not reported aedeagus eversion.
• Aedeagus eversion in response to spinosyns has not been previously observed in any insect species.

Purpose of the Study:

• To investigate the aedeagus eversion response in male sap beetles exposed to spinetoram and spinosad.
• To determine if this response is dose-dependent.
• To assess if other coleopteran species exhibit similar responses to spinetoram.

Main Methods:

• Sap beetles were treated with varying rates of spinetoram and spinasod.
• Three species of Coccinellidae and one species of Curculionidae were exposed to spinetoram.
• Male and female sap beetles were observed for aedeagus eversion.
• Control groups were maintained for comparison.

Main Results:

• Male sap beetles consistently everted their aedeagi when exposed to both spinetoram and spinosad.
• Females of the same species did not display an analogous response.
• No aedeagus eversion was observed in the tested Coccinellidae or Curculionidae species.

Conclusions:

• Aedeagus eversion is a specific, sex-limited response of male sap beetles to spinosyn insecticides.
• This finding adds novel information to the known toxicological effects of spinosyns.
• The response is specific to sap beetles and not observed in other tested Coleoptera families, suggesting species-specific physiological reactions to spinosyns.