A diverse assemblage of moths feeding on aphid honeydew

Adult butterflies and moths (Lepidoptera) use their proboscises to feed on flower nectar and other types of liquid food. Aphids frequently secrete honeydew from their anuses, attracting various types of insects, such as ants. Adult lepidopterans are also known to feed on aphid honeydew. However, very few studies have clarified the species composition and morphology of moths feeding on aphid honeydew. In late June 2017, we found nocturnal moths sipping honeydew secreted by Shivaphis celti and Sitobion cornifoliae (Hemiptera: Aphididae) on leaves of Celtis sinensis (Cannabaceae) and Cornus kousa (Cornaceae), respectively, at the edge of a secondary forest in central Japan. The moths were observed to uncoil their proboscises and feed on honeydew on the leaves. No moths were observed to feed on honeydew directly from aphids. Nocturnal moths of 60 species (11 families) and 16 species (7 families) were collected from honeydew on Ce. sinensis and Co. kousa leaves, respectively. Eleven moth species were shared between the two types of honeydew. The most abundant species, Oncocera semirubella (Lepidoptera: Pyralidae), accounted for 44.7% of all individuals. The sex ratio of O. semirubella was female biased. Of the 65 moth species collected on aphid honeydew, 52.3% (34 species) have been previously reported to visit flowers. Moths visiting honeydew had relatively short proboscises and small body size. These results suggest that aphid honeydew is an important, accessible food resource for moths of small size. [Display omitted] •Diverse nocturnal moths fed on aphid honeydew.•Honeydew-feeding moths had relatively short proboscises and small body size.•Aphid honeydew may be an important food resource for moths of small size.