Swarming Bevahiour in Sciara hemerobioides

Sciara hemerobioides swarming

A subject of a previous post, Sciara hemerobioides, was recently observed swarming around False Oat Grass (Arrhenatherum elatius), seemingly feeding on the seeds of the grass, in a coastal area. I find this quite odd, as any references I have found to adult S. hemerobioides feeding have put then feeding on the nectar of umbelliferous plants (1) and adults can only ingest liquids. No mating, or interest in mating, was observed in any of the flies. The all seemed to be actively feeding at the grass seed head.

Sciara hemerobioides swarming

References:

1. Menzel et al., 2006. Zoological Journal of the Linnean Society 146 pp. 1-147

Yellow Bellied Fly

Sciara hemerobioides

The dark winged fungus gnats (Sciaridae) are a large family of flies (c. 1,700 species worldwide (1)), with 104 species alone described in Ireland (2). They are commonly found in moist environments, and some the larvae of some species are pests of commercial mushroom farms, specifically Lycoriella mali (3).

Sciara hemerobioides

Normally these 1 – 11 mm long flies are quite drab in appearance, with black bodies and appendages and dark wings (as the common name suggests). However one species that bucks the trend is Sciara hemerobioides. While its head, thorax, legs and wings are dark like other Sciaridae, it has a bright yellow abdomen with bold black strips across it. The adults can be seen in a variety of damp habitats, such as heathlands and wetlands, where the adults feed on nectar from umbelliferous flowers (4). The larvae feed on fungi and rotting vegetation.

References:

1. Surhone et al., 2010. Sciaridae p. 7
2. Ferriss et al. 2009, Irish Biodiversity: A Taxonomic Inventory of Fauna p. 100
3. Mullen et al., . Medical and Veterinary Entomology pp. 137-138
4. Menzel et al., 2006. Zoological Journal of the Linnean Society 146 pp. 1-147