none Six mutant larvae of Lymantria dispar (L.) were found in Sekigahara, Aichi Prefecture, Honshu, Japan, in June 1977. The distinctive "black-backed" mutant late-stage larvae had nearly solid black dorsum. Otherwise, all setae, veruccae, and dorsal glands were colored as in normal larvae. All mutant larvae died of natural enemies, thus the authors could not determine if mutant larvae produced distinctive adults. The mutant appeared in less than 1% of the total population. Colour and luminescence; Colour; Markings; Genetics; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Diseases and disorders; Diseases; Microbial diseases; Ecology; Population dynamics; Land and freshwater zones; Palaearctic region Blepharipa (Tachinidae ); Apanteles liparidis (Braconidae ); Lepidopteran hosts; Lymantria dispar; Blackbacked mutant host larvae; Japan; Honshu; Aichi Prefecture; Sekigahara; Lepidopteran host, blackbacked mutant larvae Lymantria dispar (Lymantriidae); Melanism; Larval mutant, black dorsum; Mutation; Blackbacked larva; Japan & South Korea; Dipteran parasites; Blepharipa; Hymenopteran parasites; Apanteles liparidis; Fungal diseases; Entomophthora aulicae, blackbacked larval mutant & normal larvae; Mortality; Fungal disease & insect parasites, blackbacked larva mutant; Japan; Honshu; Aichi Prefecture; Sekigahara; Blackbacked mutant larvae, natural mortality; South Korea; Taejon; Blackbacked mutant larvae recorded