Behavioral and Physiological Response of Eucosma giganteana to Semiochemicals From Conspecifics and Silphium integrifolium

ABSTRACT

Eucosma giganteana is a specialist herbivore on Silphium spp. and a major limiting factor to the commercialization of Silphium integrifolium , a perennial oilseed crop. Although it is known that ( E )‐8‐dodecenyl acetate works as an attractant to E. giganteana , it is unknown whether it responds in a concentration‐dependent manner, and whether this cue works throughout the season. Also unknown is whether these moths behaviorally or physiologically respond to other important semiochemicals, such as those emitted by conspecifics or its host. This information is important for developing volatiles for use in behaviorally‐based management of E. giganteana. To address our questions, we performed field trapping with traps baited with ( E )‐8‐dodecenyl acetate, characterized headspace emissions from E. giganteana , and used EAG and flight mill analysis to assess response to ( E )‐8‐dodecenyl acetate and volatiles derived from S. integrifolium and conspecifics. Higher loadings of ( E )‐8‐dodecenyl acetate in the field trapping studies conducted in 2024 resulted in increased captures of E. giganteana moths on sticky traps, which successfully monitored E. giganteana through their full flight period. EAG showed antennal depolarizations, which confirmed E. giganteana perceive ( E )‐8‐dodecenyl acetate. In addition, female E. giganteana perceive volatiles emitted by S. integrifolium whereas males did not. Despite eliciting clear antennal responses and showing success in field monitoring, ( E )‐8‐dodecenyl acetate did not influence flight behavior during the flight mill experiments under the tested conditions. Altogether this study shows ( E )‐8‐dodecenyl acetate successfully monitored E. giganteana through the field season; more work is required to deploy it in behaviorally‐based management IPM tactics.