Wetland detritus effects on survival and development of the northern house mosquito (Culex pipiens)

Detritus and associated microorganisms are important food resources for larval mosquitoes. Prior studies have compared the effects of different detritus types on mosquito competition in container systems where predation is often rare and food resources are limiting. Detritus type is likely to be an important factor affecting larval mosquito development in temporary wetlands but few studies have addressed the effects of detritus type on mosquito development in these systems. We tested whether the effect of different wetland detritus types altered the effect of larval crowding by raising Culex pipiens larvae at different densities under standard laboratory conditions with one of four common wetland detritus types (three emergent plant species: Phragmites australis, Typha latifolia, Juncus effuse; and mowed grass, Festuca arundinacea) as the nutrient base. We found that larvae raised in grass produced the largest adults in the fastest time, but few larvae reached adulthood regardless of density. Mosquitoes raised in Juncus effuse were the smallest at adulthood and had the longest development time among all detritus types at high densities. There was little difference between mosquitoes raised in Phragmites australis and Typha latifolia. Our results indicate wetland detritus type may be an important factor influencing mosquito development and production in wetlands by altering the effects of crowding or having variable toxicity impacts.