Comparison of Survival and Development of Gypsy Moth Lymantria dispar L. (Lepidoptera: Erebidae) Populations from Different Geographic Areas on North American Conifers.

Melody A Keena,Jessica Y Richards

doi:10.3390/insects11040260

Melody A Keena, Jessica Y Richards

Open Access

https://doi.org/10.3390/insects11040260

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Abstract

Host utilization information is critical to managers for estimating the hosts at risk and potential geographic range for gypsy moths from different geographic origins. In this study, the development and survival of gypsy moths from all three subspecies on 13 North American conifers and three broadleaf hosts were compared. There was variation in the ability of gypsy moth larvae from different geographic origins to utilize (survive and develop on) key North American conifers. However, that variation was not consistent within gypsy moth subspecies, but instead was more consistent with populations from different origins being preadapted to utilize different hosts and having different biologic traits. Some Asian populations developed and survived well on some conifers while populations from Europe and North America gained weight faster and/or survived better than some Asian populations. Although development was slower and survival poorer on several of the conifers, first instar larvae were able to utilize conifers unless the needles were tough or feeding deterrents were present. Host phenology was also critical since the early instars fed preferentially on new foliage or buds. Gypsy moth larvae can utilize many hosts, so this makes it a very adaptable invasive species that warrants taking measures to prevent its spread.

Highlights

Generalist herbivores tend to be more widespread than specialists and the breadth of their diet can vary over their geographic range
Host utilization information is critical to managers for estimating the hosts at risk and potential geographic range for Asian gypsy moths from different geographic origins in North America
Using smaller trees that may have somewhat different phenology and secondary compounds compared to more mature trees may have impacted the ability of the larvae to use some of the hosts. These results suggest that the measures being taken to prevent establishment of gypsy moths of all subspecies in western North America is warranted given the risk to the economically important conifers found there

Summary

Introduction

Generalist herbivores tend to be more widespread than specialists and the breadth of their diet can vary over their geographic range. Some populations may become more specialized than others, especially if they are small or geographically isolated. Coevolutionary theory proposes that differences between herbivore populations have arisen through taxon-specific histories of reciprocal adaptations that the herbivore has with its native or local host plants. Plants have multiple potential defenses—structural, phenological, chemical, and through associations with other organisms that protect them—and they can evolve independently, so herbivores must either adapt to any new defense or evolve phenotypic plasticity to deal with a range of defenses. The more variable the environment the herbivore finds itself in the more plastic phenotypes will be favored [2]

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