Geographic variation in performance of a widespread generalist insect herbivore. (15th January 2020)

• Record Type: Journal Article
• Authors: Vidal, Mayra C.; Lill, John T.; Marquis, Robert J.; Murphy, Shannon M.
• Is Part Of: Ecological entomology. Volume 45:Number 3(2020)
• Page Start: 617
• Page End: 625
• Publication Date: 2020-01-15
• Subjects: Bottom‐up effects -- diet breadth -- fall webworm -- fitness -- insect herbivore -- performance; Insects -- Ecology -- Periodicals; Entomology -- Periodicals; 595.7
• DOI: 10.1111/een.12833
• Languages: English
• ISSNs: 0307-6946

Abstract

Abstract : 1. Generalist herbivores are often widespread and occur in a variety of environments. Due to their broad distribution, it is likely that some populations of generalists will encounter host plants with geographic variation in traits that could affect the herbivore's growth and survival (i.e. performance). However, the geographic pattern of performance has rarely been studied for generalists, especially across large geographic ranges. 2. This study used one of the most generalist herbivore species known, the fall webworm ( Hyphantria cunea Drury 1773, Erebidae, Lepidoptera), to experimentally test how the performance of a local population of fall webworms varies with increasing geographic distance of the host plant population from the local herbivore population. Specifically, a transplant experiment was used to compare the performance of one fall webworm population feeding on its local host plants with its performance on host populations from two other locations, 1300 and 2600 km away. 3. It was found that fall webworms performed better on their local host plant populations than on populations from other regions, with performance at its lowest when reared on hosts of the same species from the farthest region. It was also found that local fall webworms do not perform well on hosts commonly used by fall webworms at the other two, more distant sites. 4. This study helps to elucidate how the performance of generalist herbivores varies along their geographic range and suggests possible local adaptation to different sets of hosts across sites. Abstract : An extreme generalist herbivore, the fall webworm, was used to test how its performance would vary on host plant populations 1300 and 2600 km away from the local population. Fall webworm performance decreased with increasing distance of the host plant population, a finding that helped to elucidate how performance of generalist herbivores varies along their geographic range. It was also found that local fall webworms do not perform well on hosts commonly used by other populations of fall webworms, suggesting possible local adaptation.