Effects of Temperature on Development of Lymantria dispar asiatica and Lymantria dispar japonica (Lepidoptera: Erebidae)

Abstract

Periodic introductions of the Asian subspecies of gypsy moth, Lymantria dispar asiatica Vnukovskij and Lymantria dispar japonica Motschulsky, in North America are threatening forests and interrupting foreign trade. Although Asian gypsy moth has similar morphology to that of European and North American gypsy moth, it has several traits that make it a greater threat, the most important being the flight capability of females. Asian gypsy moth is not yet established in North America; however, infestations have been detected multiple times in Canada and the United States. To facilitate detection and eradication efforts, we evaluated the effect of a range of temperatures on development time, survivorship, and fertility of eight populations of Asian gypsy moth. There were significant impacts of temperature and population on these life history characteristics. The larval developmental rate increased with temperature until it reached an optimum at 29 °C. Larvae experienced significant molting problems at the highest and lowest temperatures tested (10 °C and 30 °C). At 30 °C, female fitness was markedly compromised, as evidenced by reduced fecundity and fertility. This suggests that development and survival of Asian gypsy moth may be limited by summer temperature extremes in the Southern United States. We also determined the degree-day requirements for two critical life stages and two populations of Asian gypsy moth, which represent the extremes in latitude, to predict the timing for biopesticide application and adult trap deployment. Our data will benefit pest managers in developing management strategies, pest risk assessments, and timing for implementation of management tactics.

Assessing the Potential Distribution of Asian Gypsy Moth in Canada: A Comparison of Two Methodological Approaches

“…Suitable conditions for AGM were modelled in areas with annual temperatures between 5 and 25 °C, but the optimum range (probability of presence >0.60, based on maximum test sensitivity and specificity threshold 32 ) was between 11-25 °C. This optimum range is in agreement with the recent findings of Limbu et al 12 that AGM populations may struggle in regions that experience longer periods of temperatures ≥30 °C and that AGM survival was highest between 15 and 25 °C. Canadian areas classified as suitable were located within the Koppen-Geiger climatic zones-DFb (average temperatures below 22 °C) and DFc, which represents subarctic climate where 1-3 months have an average temperature above 10 °C.…”

“…Currently, gypsy moth is spreading in North America (primarily in the United States) damaging both commercial and native forest ecosystems over much of the introduced range. The pest also poses a significant economic threat to several other countries that are taking actions to prevent its introduction 12 . Two subspecies, Asian gypsy moth (L. dispar asiatica Vinkovskij), distributed throughout temperate Asia, and the Japanese gypsy moth (L. dispar japonica Motschulsky), distributed throughout Japan, are of serious concern although they have not yet permanently established (though several incursions have been eradicated) outside their native range 13,14 .…”

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

“…Time to adult differed between some hosts but there was almost no significant variation between populations within a host. Female pupae from the Korean, Japanese, and Chinese populations tended to be larger, which is consistent with earlier work on these same populations [30]. Significant variation in fecundity was tied more to larval host than population, with the highest fecundity for females reared on Q. velutina and P. menziesii.…”

Climate‐related geographical variation in performance traits across the invasion front of a widespread non‐native insect

“…Many of these studies focused on the effects of cold temperatures, particularly shortened season lengths in colder climates, the amount of cold necessary for egg hatching and limitations on egg viability constraining northward expansion (Gray et al., 1991; Madrid & Stewart, 1981; Streifel et al., 2019). More recent work has expanded these questions to include warm temperatures (Banahene et al., 2018; Limbu et al., 2017). This area of research has shown that a range retraction along the southeastern invasion front is correlated with supraoptimal temperatures (Tobin et al., 2014) and provides support for local adaptation of fitness‐related traits in southern populations (Faske et al., 2019; Friedline et al., 2019; Thompson et al., 2017).…”