Asian Gypsy Moth
Host utilization information is critical to managers for estimating the hosts at risk and potential geographic range for Asian gypsy moths (AGM) in North America. Since the lists of hosts that AGM is known to feed on in other countries is long and no broad evaluation of North American hosts has been performed, it is difficult to evaluate how the hosts at risk in North America to the Asian and established gypsy moths may differ.
The European gypsy moth established across much of eastern North American are able to feed on a wide variety of tree species, with 148 host trees identified as highly susceptible hosts out of a total of 449 tree species that larvae can feed and complete development on. The two genera with the most susceptible species are oaks (quercus) and willows (salix), with the remainder of the highly susceptible species coming from 28 other tree genera (including larches (larix).
AGM larvae utilize many of the same host tree genera as established gypsy moths and have been reported to feed on 316 species from 61 orders and 130 genera. Asian gypsy moth is known to outbreak on different hosts throughout its range, including oak-, birch-, and larch-dominated forests and mixed broadleaf forests. Previous laboratory studies generally showed that the Asian populations evaluated could utilize many of the hosts from other world areas, and some populations developed faster and survived better on hosts considered marginal for European gypsy moths established across North America.
Our study compared the host utilization of gypsy moths from all three subspecies, originating from multiple countries, on 13 key North American conifers and three broadleaf hosts. Variation between and/or within a subspecies in host utilization was assessed using survival and developmental data (either to 14 days or to adult with reproductive traits also evaluated).
The second study is using RNA to evaluate the genes that are expressed when gypsy moth larvae from different origins feed on conifers.
Through this research, we expect to understand how host utilization differs among and within gypsy moth subspecies to better predict the risk to key North America tree species.
There was variation in the ability of gypsy moth larvae from different geographic origins to 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 those already established in 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.
Our research shows that gypsy moth larvae can utilize many hosts, so this makes it a very adaptable invasive species that warrants taking active and aggressive measures to prevent its spread.
Keena, Melody A.; Richards, Jessica Y. 2020. Comparison of Survival and Development of Gypsy Moth Lymantria dispar L. (Lepidoptera: Erebidae) Populations from Different Geographic Areas on North American Conifers. Insects. 11(4): 260. 17 p. https://doi.org/10.3390/insects11040260.
- Melody Keena, USDA Forest Service- Northern Research Station Research Entomologist
- Jessica Richards, USDA-Forest Service, Northern Research Station Biological Sciences Laboratory Technician
- Chris Keeling, Laurentian Forestry Centre, Natural Resources Canada,and Universite Laval, Institut de Biologie Integrative et des Systemes
- Ilga Porth, Universite Laval, Institut de Biologie Integrative et des Systemes
- Last modified: May 27, 2020