Some moths, such as winter moth, mottled umber moth, Erannis defoliaria and March moth, Alsophila aescularia, emerge as adults in the colder months of the year. These moths have fully winged males but the females have vestigial wings that are reduced to small stubs and cannot fly.
Most moths lay their eggs in batches on suitable food plants for their caterpillar larvae. After hatching, some caterpillars stick together (see our page on gregarious larvae
), but most disperse and lead solitary lives
The caterpillars will shed their outer skins
on several occasions as they develop and increase in size. When fully fed, the caterpillars wander away from their food plants and often burrow into the soil where they will pupate. During the pupal stage, the caterpillar’s tissues are broken down and rebuilt to produce the adult moth. Some moths have more than one generation a year. Depending on the species, moths can overwinter as adults, eggs, larvae or pupae. Most moth pupae are hidden in the soil, although some, such as the puss moth Cerura vinula
and the burnet moths construct silken cocoons on twigs or grass stems.
Role of moths in gardens
Adult moths cause no damage to plants as their feeding is restricted to taking nectar from flowers. Only a small minority of moths have larvae that cause sufficient damage to garden plants to be considered pests. The rest have little or no impact on cultivated plants. Some adult moths visit flowers to feed on nectar. While doing so they can pick up pollen on their bodies and assist in the pollination process.
The largely nocturnal activity of adult moths means they are important prey items for bats
and nightjars. The caterpillars of moths are often heavily predated by birds and various parasitic insects. The breeding success of birds such as the blue tit and great tit1
, is related to the availability of caterpillars during the birds’ breeding season.
Other sources of information
1. Naef-Daenzer, Luzia & Naef-Daenzer, Beat & G. Nager, Ruedi. (2000). Prey selection and foraging performance of breeding Great Tits Parus major in relation to food availability. Journal of Avian Biology 31. 206-214.
OPAL moth tips 1
- getting started in garden moth trapping (Books and moth traps)
OPAL moth tips 2
- introduction to the families of British and Irish macro-moths
OPAL moth tips 3
- introduction to the families of British and Irish micro-moths
Goater B., Senior G. and Dyke R. (1986) British Pyralid Moths: a Guide to their Identification. Harley Books
James, D.G. (2017) The Book of Caterpillars. Ivy Press (Not for identification use! International in scope, but a fascinating and well illustrated compendium of caterpillar diversity)
Porter, J. (2010) Colour Identification Guide to the Caterpillars of the British Isles. Apollo Books
Skinner, B. (2009) Colour Identification Guide to the Moths of the British Isles. Apollo Books
Sterling, P., Parsons, M. and Lewington R. (2018) Field Guide to the Micro-moths of Great Britain and Ireland. British Wildlife Publications
Sterling, P., Henwood, B., Lewington, R. (2020) Field Guide to the Caterpillars of Great Britain and Ireland
Bloomsbury Wildlife Guides
Townsend, M. Waring, P. and Lewington R. (2018) Concise Guide to the Moths of Great Britain and Ireland. British Wildlife Publication
Randle, Zoe et al 2019 Atlas of Britain and Irelands's Larger Moths. Nature Bureau
Page drafted and compiled by Steve Head