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| A collage of oak galls created by oak gall wasps. Credit: Kirsten Prior |
Climate change has led to warming temperatures in the Pacific Northwest, leading some insect species to expand their range into more northerly oak savannas, according to new research from Binghamton University, State University of New York.
Side by side, Dylan Jones displayed photos of two oak leaves. One, healthy and green, dotted by the occasional gall, a structure made by a herbivorous species of oak gall wasp. The other leaf was yellowed and tattered, the victim of an insect population without predatory checks and balances. Climate change has led to warming temperatures in the Pacific Northwest, leading species such as Neurotereus saltatorius to expand their range into more northerly oak savannas.
“In the native range, you might find a handful of galls on a single leaf. In the expanded range, sometimes you’re finding thousands on a single tree,” said Assistant Professor of Biological Sciences Kirsten Prior. “This is pretty prevalent throughout Vancouver Island.”
Jones, a Binghamton University doctoral candidate in biological sciences and Clifford D. Clark Diversity Fellow, is the lead author of a research paper recently published in the Journal of Animal Ecology on the situation. Co-authors on “Latitudinal gradient in species diversity provides high niche opportunities for a range-expanding phytophagous insect” include Prior, field technician Julia Kobelt, then-undergraduate Jenna Ross and Assistant Professor of Biological Sciences Thomas Powell.
Oak savannas are grassy and shrubby areas that feature oaks as the dominant tree species. The oak species in question — Quercus garryana — requires a dry environment. As a result, oak savannas are often found in the rain shadow of the West Coast’s mountain range, Prior explained.














