Density,production and life cycle of Brachycentrus subnubilus Curtis (Trichoptera: Brachycentridae) in a lowland river,Central Poland

The annual mean density of Brachycentrus subnubilus a trichopteranspecies with a univoltine life-cycle was 572 ind. m^-2. Itconstituted of only 2.1% of the total macrozoobenthos abundance,while this species in terms of biomass exceeded 11.9% of the totalbenthic biomass. Production of Brachycentrus subnubilus was estimated bysize-frequency method was 26.56 g wet weight m^-2 and theturnover ratio was 5.7.     

Predation byOligotricha striata caddis larvae on amphibian eggs: Effects of a high quality food on growth rate

In the field and also in the laboratoryOligotricha striata trichopteran larvae were observed to feed onRana temporaria eggs. Laboratory experiments revealed thatO. striata larvae preferred amphibian eggs to plant matter. The jelly-like sheath of the eggs was easily penetrated. A larva consumed 1 to 2 eggs per day. The supply of high quality food in the form of amphibian eggs was found to accelerate the growth ofO. striata larvae.