Effect of seasonality and pond permanence on aquatic insect emergence from grassland ponds

Abstract

The objectives of this study were to examine the effects of seasonality and pond permanence on aquatic insect emergence. Pond permanence is based on 3 pond types: permanent ponds that continuously hold water, semi-permanent ponds that dried and refilled with water, and temporary ponds. We conducted the present study in 14 human-made farm ponds at the Lyndon B. Johnson (LBJ) Grasslands in North Texas. Emergent insects were collected on 9 dates from March through July in 14 ponds. Nine taxonomic groups of aquatic insects were captured in adequate numbers for analysis: Odonata: Anisoptera (dragonflies) and Zygoptera (damselflies); Ephemeroptera (mayflies); Trichoptera (caddisflies); and Dipterans: Tipulidae (crane flies); Chaoboridae (phantom midges); Chironomidae: Tanypodinae (predatory chironomids) and Chironominae/Orthocladinae (herbivorous and detritivorous chironomids); and Ceratopogonidae (biting midges). We found both a seasonal effect and effect of pond type in several taxa, with seasonal flux dependent on emergent insect size and pond permanence.