Distribution Data Support Warm Winter Temperatures as a Key Limit on the Range of a Goldenrod Gall Fly Host Race

Publication Date

2017

Description

Climate change has the potential to negatively impact organisms adapted to cold winters. Eurosta solidaginis (Goldenrod Gall Fly ) is a model organism for the study of cold tolerance in insects. The Goldenrod Gall Fly occurs as distinct host races on species of the goldenrod genus Solidago. The 2 well-studied host races exhibit high fidelity to their host-plant species on which they mate, lay their eggs, and overwinter as larvae. One host race, associated with Solidago altissima (Late Goldenrod) and referred to as the altissima host race, occurs virtually throughout its host-plant’s range across the eastern North America. Although S. gigantea (Giant Goldenrod) shares much the same range as S. altissima, the host race on S. gigantea referred to as the gigantea host race, is restricted to the northern portion of its host-plant’s range. We developed hypotheses to account for both the limited, northerly range of the gigantea host race as well as the widespread range of the altissima host race, which includes the southern US. Our first hypothesis is that the gigantea host race is limited by warm overwintering temperatures, which result in higher energetic losses over winter. This limitation would differentially affect the 2 host races given that altissima flies have greater mass and our data on egg production showed that smaller gigantea females produce fewer eggs than altissima females making it difficult to overcome such energetic losses. Our second hypothesis is that adult emergence times, which can be affected by spring temperatures during pupation, detrimentally alter the synchronization of host-plant and insect phenologies. Using presence–absence records and modeled proxies for winter energy loss and spring development time based on PRISM climate data, we conducted an auto-logistic regression on both proxies plus a spatial auto-covariate. This analysis supports the hypothesis that winter energy loss limits the geographic distribution of gall flies on S. gigantea. Climate and landscape changes, including cooling and deforestation during European settlement of northeastern US and southeastern Canada, were likely favorable for the S. gigantea host race. Ongoing climate and landscape change in the opposite direction will likely reduce the range and population size of the gigantea host race.

Journal

Northeastern Naturalist

Volume

24

Issue

Special Issue 7B235

First Page

235

Last Page

250

Department

Biology

This document is currently not available here.

Share

COinS