Aphomia sociella Bee Moth, the perfect inquiline?

♀ Aphomia sociella Bee Moth

Aphomia sociella is a rather attractive, relatively large micro moth of the Pyralid family. Despite its rather specialised life history (see below), it is fairly common and widespread in this part of the world. This female was found resting low (15 cm up) on a shed wall this evening, above a thicket of Herb Robert Geranium robertianum. The photograph is poor due to low light (handheld ½ sec. shutter speed!) and does not do the moth justice.

Like some other members of the subfamily Galleriinae, the larvae inhabit the nests of bumblebees Bombus and wasps Vespula, typically those that are above ground like the recently-arrived Tree Bumblebee Bombus hypnorum, which is one of the commonest species in our garden. Initially they consume waste materials, debris and old cells, but can eventually graduate to devouring the comb and bee larvae, leaving the nest riddled with silk-lined tunnels.

Since Bee Moth caterpillars mostly feed on nest materials, waste products of the bee and wasp larvae, as well as on dead adults, they are neither parasitic nor necessarily predatory, and so are denominated inquilines (cf. L. inquilinus, Fr. inquilin, Sp. inquilino = lodger) – animals that live as commensals in the nest, burrow or dwelling place of other animals. Bee Moths are not an apicultural pest, since they only rarely infest Honeybee colonies, but they have been introduced into E USA (Opler et al. 2012) where they may have an impact on native North American bumblebees.

Photographs and video of Bee Moths and their bumblebee hosts can be found here.


References

Goater, B. (1986) British Pyralid moths: a guide to their identification. Harley Books, Colchester, Essex. 175 pp.

Opler, P.A., K. Lotts & T. Naberhaus (coordinators) (2012) Bee Moth Aphomia sociella (Linnaeus, 1758). In: Butterflies and Moths of North America. Data set accessed on 28/05/2014 at http://www.butterfliesandmoths.org/species/Aphomia-sociella

The Natural History Museum Identification and Advisory Service (n.d.) Bee Moth Aphomia sociella. IAS Sheet #7. The Natural History Museum, London. 2 pp. PDF