Parasitism of Scarabaeidae by Parasitoid Flies in British Columbia and Western USA: Informing Biological Control Programs Against Popillia japonica with Crowd-sourced Records of Non-target Scarab Beetles

Following the 2023 Port Coquitlam introduction of the parasitoid fly Istocheta aldrichi to suppress a population of the invasive scarab beetle Popillia japonica, I used crowd-sourced online data (44,200 observations in BC and Western USA) to determine: scarab species occurrence; which species may be attacked by parasitoid flies; whether any bore eggs that resemble I. aldrichi; and the relative risk of I. aldrichi attack for each taxon based on phenological and phylogenetic characteristics. Observed in iNaturalist were 111 species from eight scarab subfamilies. Only 17 scarabs were observed with structures resembling parasitoid eggs present. I categorized observed eggs into groups based on morphological characteristics; nine were categorized into the same group as I. aldrichi eggs. The Rutelinae and Dynastinae subfamilies had the highest relative risk. This work will help prioritize further host range testing and guide decisions about whether to introduce I. aldrichi to other regions.

Author dc:creator

• Walmsley, Scott

Advisor dc:contributor.advisor

• Moran, Jonathan

• School of environment and sustainability

Language dc:language.iso

en_US

Identifier URI

https://doi.org/10.25316/IR-20936

OAI identifier oai:identifier

oai:null:10613/29406