Assessing risk of Lymantria dispar L. invasion management to monarch butterflies (Danaus plexippus)

Abstract

Conflicting conservation goals that lead to management tradeoffs are not uncommon in conservation practice. In this study, we explore a potential conflict between the management of a destructive invasive insect pest, Lymantria dispar, and conservation of a widely declining iconic species, the monarch butterfly (Danaus plexippus). Specifically, we assess the risk of exposure of susceptible monarch larvae to aerial applications of Btk, a Lepidoptera-specific larvicide used in L. dispar suppression and eradication. Our findings indicate minimal conflict between L. dispar management and monarch conservation, as spatial overlap between Btk aerial applications and monarch larvae was found to be marginal. Furthermore, the results of our study indicated specific actions management can take to further minimize potential conflict between these conservation goals. Our study could serve as a guide to other efforts to evaluate potential tradeoffs between the management of invasive species and the conservation of vulnerable species.