Neuroterus saltatorius (jumping gall wasp) phenology and abundance in native and expanded ranges

Abstract

Neuroterus saltatorius (Hymenoptera: Cynipidae), also known as the jumping gall wasp, is native to Oregon and Washington, but is experiencing ecological release, and expanding into British Columbia. Galls are modified plant tissues that form around a developing wasp egg after oviposition into leaves. N. saltatorius forms galls exclusively on Quercus garryana (Garry oak) leaves throughout its territory. Abnormally large numbers of galls damage Q. garryana populations in British Columbia, which are already susceptible from human and animal interactions. To understand the ecological impact of the N. saltatorius range expansion, I compare the average gall numbers and phenological variation in its native and expanded ranges.