Causes of polymorphic melanism and its thermoregulatory function in a parasitoid wasp Meteorus pulchricornis (Hymenoptera: Braconidae)

Abstract

Abstract. We investigated the variation in body colour and its thermoregulatory function in Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae), a parasitoid wasp of Spodoptera and other free-living lepidopteran larvae. We show that the body colour of adult wasps darkens when cocoons are kept at low temperatures. The range in the variation in colour, however, differs for different parts of the body and among uniparental (thelytokous) strains. This melanism enables these wasps to attain a body temperature in sunshine up to 2°C. Moreover, this small gain in body temperature can markedly increase the flight activity of wasps at low ambient temperatures. We conclude that the variation in body colour that resulted from rearing the cocoons at different temperatures enable the wasps to adapt to changing thermal environments. The ecological significance of the difference in the degree of melanism of the different strains is discussed.

Polyphagous koinobiosis: the biology and biocontrol potential of a braconid endoparasitoid of exophytic caterpillars

“…Probably due to its high polyphagy, M. pulchricornis shows high genetic diversity and environmental plasticity in adult melanism (Abe et al 2013).…”

“…Meteorus pulchricornis is a solitary koinobiont endoparasitoid of lepidopteran larvae. Its general bionomics (Askari et al 1977;Fuester et al 1993; Suzuki and Tanaka 2007;Takashino et al 2001), adult diet (Wu et al 2008), circadian activity (Nishimura et al 2015), courtship and mating behavior (Askari and Coppel 1978), oviposition behavior (Chau and Maeto 2009; Kageyama and Sugiura 2016;Sheng et al 2015;Yamamoto et al 2009;Zhou et al 2017), adaptive melanism (Abe et al 2013), superparasitism Maeto 2008, 2009;Zhang et al 2014), immune suppression mechanism (Suzuki and Tanaka 2006;Suzuki et al 2009), mitochondrial genome (Wei et al 2010), and modes of reproduction (Tsutsui et al 2014) have been studied.…”

Daily locomotor activity of the parasitoid wasp Meteorus pulchricornis (Hymenoptera: Braconidae) that attacks exposed lepidopteran larvae

“…6 The mean locomotor activity (±SD) of the eight female wasps transferred from 16L8Dim to DimDim. The gray background represents the scotophase (Dim), and the white background represents the photophase (L) went up to 35 °C within several minutes on a sunny day in May when the ambient air temperature was about 25 °C (Abe et al 2013). Inactivity in the daytime seems reasonable to avoid heating up in the strong sunshine, although despite this many chalcid wasps are known to be diurnal (see Introduction).…”

“…The strain is light in body color and apomictic ("KAGAWA_01_U" of Abe et al 2013 andTsutsui et al 2014), and it has been successively maintained on S. litura larvae reared on an artificial diet (Insecta LFS, Nosan, Kanagawa). Adult wasps were reared on 50 % honey solution under a 16L8D photoperiod (16 h light:8 h complete darkness) at 15 °C.…”

An illustrated key to Neotropical species of the genus Meteorus Haliday (Hymenoptera, Braconidae, Euphorinae)

“…Huddleston pointed out upon the unreliable color variability in identifying species. In fact, color pattern is a variable that might be affected by environmental conditions (Abe et al 2013) and may display a broad spectrum of change in species widely distributed. However, a careful examination of abundant species present in Colombia, Costa Rica and Ecuador support the use of such a trait in several cases.…”