Gypsy moth parasitoids in the declining outbreak in Lithuania

Abstract

A 3 year study was conducted on the parasitoids of gypsy moth larvae in two reducing outbreak areas in Lithuania. Overall parasitism of 25.0 ± 2.0% in the first post‐culmination year was significantly lower than the 36.3 ± 1.4 and 35.2 ± 1.4% parasitism in the two subsequent years. When analysed in terms of the life stage at which the host was collected, the total parasitism over 3 years was constantly increasing from 3.1 ± 0.8 in the first to 72.5 ± 2.9% in the sixth instar. Parasetigena silvestris R.‐D. dominated causing 48.7 ± 1.5% parasitism and 16.7 ± 0.6% larval mortality preferably in late instars. Phobocampe disparis Vier. contributed to 21.9 ± 1.2% parasitism and 7.5 ± 0.5% mortality recovering from early instar larvae. Meteorus pulchricornis Wes. parasitized 4.3 ± 0.6% gypsy moth larvae causing 1.5 ± 0.2% mortality and a few Apanteles species provided 2.8 ± 0.6% parasitism and 1.0 ± 0.2% mortality. The gypsy moth in Lithuania was reported to act as host for Rogas sp. (Hym., Braconidae) and Siphona boreata Mes. (Dipt., Tachinidae).

Spatial and temporal variation in the parasitoid assemblage of an exophytic polyphagous caterpillar

“…3). This tachinid species richness is significantly higher than the mean recorded for other exophytic Lepidoptera (with comparable sample sizes) based on Hawkins's (1994) host–parasitoid database (mean ± SE = 3.42 ± 0.38, P < 0.05), however as tachinid flies are largely diurnal (Clausen, 1940), tend to attack large insect hosts (Arnaud, 1978), and often dominate parasitoid assemblages of hairy host species (Herting, 1960; Parry, 1995; Zolubas et al ., 2001), G. geneura has the characteristics that make it a preferred host for tachinid parasitism. The wide host range of many tachinid species may predispose them to attack a polyphagous host such as G. geneura that is distributed unpredictably over space and time.…”

Natural enemies and environmental factors affecting the population dynamics of the gypsy moth

“…; Zolubas et al. ). Glyptapanteles liparidis and Glyptapanteles porthetriae seem to be abundant in latency and progradations in Europe (Schopf and Hoch ; Hoch et al.…”

“…; Zolubas et al. ; Sukovata and Fuester ). These two species are specialized and univoltine, which make their life span similar to their host (Montgomery and Wallner ; Maier ).…”

“…For example, cycles have occurred in the same forests of birch and alder in western Lithuania every 10 years since the 1970s (1971–1975, 1982–1983, 1993–1994; Zolubas et al. ). In Europe, the following terms are used to describe the various phases of the cycle (see fig.…”

“…of the family Ichneumonidae cause considerable parasitism rates for the larvae and pupae in postgradations (Maier ; Zolubas et al. ). These species are oligo‐ or multivoltine.…”