Drusus annulatus (Stephens, 1837)

Drusus annulatus is one of 39 members of the Family Limnephilidae found in Ireland, and the sole member of the genus Drusus. It is a species whose larvae can be found in streams and rivers, or rarely on lake shores. Its substratum preference is for stony material from gravel to cobbles and boulders, in moderate to fast flowing water. Drusus annulatus has a curved case made of mineral grains.

In temperate areas, Drusus annulatus has a univoltine (one generation per year) or bivoltine (two generations per year) reproductive cycle, and lives for up to one year. The feeding ecology of the larvae of Drusus annulatus is almost entirely grazing, with small amounts of shredding and gathering.

Characteristic features of the larva of Drusus annulatus include a prosternal horn, dorsal protuberance on the 1st abdominal segment, antenna midway between the eye and the anterior head margin, gills with only single filament, two central anterior-median sclerites on the metadorsum, no teeth along the mandible edges, additional setae on femoral faces, lateral protuberance without a posterior sclerite and no group of pale setae between the eye and the frontoclypeal apotome.

Adults of Drusus annulatus can be found on the wing from (May) July to October.

For details of distribution records of Drusus annulatus in Ireland available through the National Biodiversity Data Centre mapping system, click here.

References

Barnard, P. and Ross, E. (2012) The Adult Trichoptera (Caddisflies) of Britain and Ireland. RES Handbook Volume 1, Part 17.

Graf, W., Murphy, J., Dahl, J., Zamora-Muñoz, C. and López-Rodríguez, M.J. (2008) Distribution and Ecological Preferences of European Freshwater Species. Volume 1: Trichoptera. Astrid Schmidt-Kloiber & Daniel Hering (eds). Pensoft, Sofia-Moscow.

O’Connor, J.P. (2015) A Catalogue and Atlas of the Caddisflies (Trichoptera) of Ireland. Occasional Publication of the Irish Biogeographical Society, No. 11.

Wallace, I.D., Wallace, B. and Philipson, G.N. (2003) Keys to the Case-bearing Caddis Larvae of Britain and Ireland. Scientific Publication of the Freshwater Biological Association No. 61.

Last updated: 18/07/2017

Advertisements