Potential Differences and Methods of Determining Gypsy Moth Female Flight Capabilities: Implications for the Establishment and Spread in Novel Habitats

Abstract

The introduction of the Asian gypsy moth into novel environments continues with frequent interceptions in North America. There is a concern that these subspecies will pose a greater threat to the forests and urban environments of North America than the established gypsy moths (Lymantria dispardispar L.), due to their greater capacity for female flight. Asian gypsy moth populations vary in many key traits, including female flight capabilities. The potential impacts of female flight, in combination with the other key traits, on the ecology and spread of this insect are first discussed in this communication. This also provides the first review of most of the current literature on the variations in flight capability and flight distance of gypsy moth populations, as well as variation in other traits of concern and the potential methods of identification, with special attention paid to the Asian subspecies Lymantria dispar japonica Motschulsky and Lymantria dispar asiatica Vinkovskij. There are currently good tools for identifying the general origin of introduced gypsy moth populations, but these do not provide enough information to effectively manage introductions. Gypsy moth key traits differ among populations, even within each subspecies of the gypsy moth, so introduction of gypsy moths from other world areas into locations where the gypsy moth is already present could result in unwanted changes in gypsy moth biology. It also appears that the introduction of flight-capable females could enhance a population’s dispersal capability and require modifications to management protocols used for flightless females. Therefore, rapid tools to assess key traits in introduced populations are needed to adequately plan for, or deal with, new introductions into novel habitats.

Phenological Features of the Spongy Moth, Lymantria dispar (L.) (Lepidoptera: Erebidae), in the Northernmost Portions of Its Eurasian Range

“…Since a reduction in the developmental SET near the northern edge of the spongy moth’s range is observed in both the European (Udmurtia) and Asian (Sverdlovsk, Tyumen and Novosibirsk oblasts) portions of the Eurasian range, we suggest that northern Eurasian populations display greater developmental plasticity in response to environmental factors than their North American counterparts, a trait that should be considered an important element of risk for rapid invasion in North America, in addition to the well-known female flight capability trait [ 50 ]. Thus, in assessing the threat posed by potentially invasive populations of L. dispar in North America, it is important to consider not only female flight capability [ 51 ] and host range [ 6 ], but also the potential for individuals to adapt to conditions of low heat availability, which could affect the rate of spread in the newly invaded environment (see also study by Ilyinykh and Krivets [ 27 ]). The ability of northern Eurasian populations to feed on conifers is the focus of a separate study by our group [ 52 ], demonstrating the clear potential for range expansion towards the taiga.…”

Rock Microhabitats Provide Suitable Thermal Conditions for Overwintering Insects: A Case Study of the Spongy Moth (Lymantria dispar L.) Population in the Altai Mountains

“…The hatched larvae release cobweb threads and are subsequently carried by the wind. This is the main method by which the SM spreads, but there is no consensus on how far the wind can carry the caterpillars [ 17 , 33 , 52 ].…”

Analyses of adult transcriptomes from four different populations of the spongy moth, Lymantria dispar L., from China and the USA

“…Female adult flight capability is the only criterion for classification of spongy moth populations as ASM 8 . While ESM females in North American populations are generally not capable of any kind of flight 14 , 15 , variability in female flight capability and activity has been observed among other strains of ESM from Europe and among populations of ASM 16 – 19 . Correlations between variations in female spongy moth flight capacity and variations in wing size and dimensions, flying muscle tissue, and wing load (mass/wing area) have been reported 15 – 17 , 20 .…”