Species profile: Halesus radiatus

July 17, 2017

Halesus radiatus (Curtis, 1834)

Halesus radiatus is one of 39 members of the Family Limnephilidae found in Ireland, and one of two members of the genus Halesus. It is a species whose larvae can be found in rivers, streams and lakes. Its substratum preference is for particulate organic matter and woody debris, in slow-flowing and standing water. Halesus radiatus has a case that is made of plant fragments and may incorporate long sticks. The larvae have no preference in relation to the water’s pH and can be found in brackish waters.

In temperate areas, Halesus radiatus has a univoltine (one generation per year) reproductive cycle. The feeding ecology of its larvae is predominantly shredding, with some predation and grazing.

Characteristic features of the larva of Halesus radiatus 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 filaments, two anterior-median sclerites on the metadorsum, mandibles with teeth along the edges and setae proximal to the large primary seta on at least one femur of the 2nd and 3rd legs. Separation from Halesus digitatus is based on a range of features and may not always be possible.

Adults of Halesus radiatus can be found on the wing from July to November.

For details of distribution records of Halesus radiatus 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: 17/07/2017

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