Abstract
Simple SummaryThe gypsy moth, Lymantria dispar, is a forest pest that is grouped into two biotypes: the European gypsy moth (EGM), found in Europe and North America; and the Asian gypsy moth (AGM), found in China, Russia, Korea, and Japan. Outbreaks of this pest result in high-density populations of larvae that can cause enormous damage to trees and forests. Studies have identified an influence of larval population density on gypsy moth development, but it is not known how EGM and AGM populations differ in their response to changing larval densities. We examined the effects of varying larval density on three colonies established from one EGM population and two AGM populations. All three colonies exhibited an optimal degree of larval survival and optimal rates of pupation and adult emergence at an intermediate density of five larvae/rearing container. The duration of larval development was fastest at the same intermediate density for all three colonies. Although differences in larval development time, survival, pupation and emergence were observed among the three colonies under the conditions of our study, our findings indicate that density-dependent effects on the development of different gypsy moth biotypes follow the same trends.The life-history traits of the gypsy moth, Lymantria dispar L. (Lepidoptera: Erebidae), have been observed to vary with larval population density, which can increase significantly during an outbreak of this pest. Laboratory studies on density-dependent variation in gypsy moth development have focused on single populations and were limited to comparing solitary larvae with groups of larvae reared at a single density. To evaluate how density-dependent impacts on development vary with different populations and subspecies of L. dispar, we compared the effects of rearing larvae of a European gypsy moth (L. dispar dispar L.) population from Connecticut, USA; and larvae of two populations of the Asian gypsy moth (L. dispar asiatica Vnukovskij) from Guizhou and Hebei provinces in China. Larvae were reared on an artificial diet at densities of one, three, five, seven, and nine larvae per 115 mL container, and the duration of larval development, percentage of surviving larvae, and the rates of pupation and emergence were measured at each density. A two-tailed response to density variation with values falling away on both sides from a peak or climbing from a base was observed for all three populations tested, with the most rapid larval development and the highest values of survival, pupation, and emergence observed at a density of five larvae/container. Although differences in larval development time, survival, pupation and emergence were observed among the different populations under the conditions of our study, our findings indicate that density-dependent effects on the development of different gypsy moth subspecies and populations follow the same trends.
Highlights
A quarantine pest is defined by the Food and Agriculture Organization of the UnitedNations (FAO) [1] as a “pest of potential economic importance to the area endangered thereby and not yet present there, or present, but not widely distributed and being officially controlled.” Quarantine insect pests are a major threat to the ecology and environment that can cause huge economic losses [2]
As one of the most destructive defoliating forest pests, the gypsy moth, Lymantria dispar (L.) (Lepidoptera: Erebidae), is a quarantine pest species with two major biotypes distributed throughout the world
One of them is the European gypsy moth, Lymantria dispar dispar (L.), which can be found in Europe and North America
Summary
A quarantine pest is defined by the Food and Agriculture Organization of the UnitedNations (FAO) [1] as a “pest of potential economic importance to the area endangered thereby and not yet present there, or present, but not widely distributed and being officially controlled.” Quarantine insect pests are a major threat to the ecology and environment that can cause huge economic losses [2]. A quarantine pest is defined by the Food and Agriculture Organization of the United. Nations (FAO) [1] as a “pest of potential economic importance to the area endangered thereby and not yet present there, or present, but not widely distributed and being officially controlled.”. Quarantine insect pests are a major threat to the ecology and environment that can cause huge economic losses [2]. Three common quarantine insect pests in forests—the hemlock woolly adelgid, the European gypsy moth, and the emerald ash borer—have been reported to cause damage to the forestry ecosystem worth approximately. As one of the most destructive defoliating forest pests, the gypsy moth, Lymantria dispar (L.) (Lepidoptera: Erebidae), is a quarantine pest species with two major biotypes distributed throughout the world. The other one is the Asian gypsy moth, including subspecies
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