Experimental studies on macroinvertebrate predator–prey impact of pesticides. The reactions of Rhyacophila and Hydropsyche (Trichoptera) larvae to Simulium larvicides

Abstract

Acute toxicity tests with the predaceous trichopteran larvae of Rhyacophila dorsalis and Hydropsyche pellucidula in a laboratory-simulated stream have shown that both species have a high survival rate after short exposures, 15 min to 1 h, to concentrations of temephos(Abate) and chlorpyrifos methyl that produce a mortality of 90% or more in late-instar Simulium larvae. A similar differential reaction to the synthetic pyrethroid permethrin was demonstrated in the case of Hydropsyche but not Rhyacophila.The implication of these findings is discussed firstly in relation to the environmental impact of Simulium control programmes based on application of larvicides to rivers and streams, and secondly to the wider problem of evaluating the impact of pesticides and allied toxic chemicals on stream ecosystems.It is concluded that although significant differences in tolerance level to some insecticides between prey (Simulium) and predator (trichopteran larvae) can be demonstrated in the laboratory, the margin of safety is not sufficiently wide to assure selective control of Simulium larvae by these chemicals under the less precise conditions of larvicide application in the field.

Acute contamination with esfenvalerate and food limitation: Chronic effects on the mayfly, Cloeon dipterum

“…The median LC50s for a 1-h exposure and 96-h observation found in the present study are comparable with previous results for Trichoptera larvae [23][24][25]. The LC50 for a 1-h exposure and 24-h observation for fenvalerate found with Limnephilus lunatus, 22.62 g/L (95% confidence interval 15.15-31.62) [23], does not differ statistically from the LC50s for a 1-h exposure and 96-h observation derived here for C. dipterum except for the lowest value found for series 1 of the LFT (Table 2).…”

Chronic effects of short-term contamination with the pyrethroid insecticide fenvalerate on the caddisfly Limnephilus lunatus

“…In Rhyacophila dorsalis Curtis and Hydropsyche pellucidula, Curtis, for example, exposed for 15 and 30 minutes, to the pyrethroid permethrin at 5 µg 1 -', mortality after 24 hours was 67% and 5%, respectively (Muirhead-Thomson, 1978 ;Muirhead-Thomson, 1979) .…”

Activity and Distribution of Carabidae, Arachnida, and Staphylinidae in New Brunswick Potato Fields

“…Permethrin is short-lived in the water column (Kingsbury andKreutzweiser 1979, 1980;Rawn et al 1979Rawn et al , 1980Rawn 198 1 ;Sharom and Solomon 198 la) and adsorbs readily onto particulate matter . Toxicity of permethrin in the water column has been studied using several aquatic insects (Gill 1977;Muirhead-Thomson 1978, 1979, but no information is available, in the primary literature, on the toxic effects of permethrin in sediment to aquatic insects. Nymphs of the burrowing mayfly, Hexagenia rigida (McDu~ough), are suitable for a study on toxicity of contaminated sediment since they inhabit and ingest sediment (Zimmerman 1977).…”