Benthic predators and zooplanktonic prey: predation by Crangonyx shoemakeri (Crustacea; Amphipoda) on Daphnia obtusa (Crustacea; Cladocera)

Abstract

Amphipods and cladocerans are common inhabitants of seasonal ponds throughout North America . Although amphipods are usually considered to be benthic detritivores, Crangonyx shoemakeri was found to capture and consume mosquito larvae and Daphnia obtusa . The rate of capture of Daphnia was independent of the amount of decomposing leaf matter available . However, this rate was dependent on prey density and the presence of light, indicating that these amphipods are visual predators . 25

Prey size and predator density modify impacts by natural enemies towards mosquitoes

“…Notonectids often dominate lentic ecosystems (Das & Gupta, ; Dalal & Gupta, ), profoundly affect ecological structuring (Blaustein, ), and are important predators of mosquito larvae (Ellis & Borden, ; Mondol et al ., ; Dalal et al ., ; Cuthbert et al ., ). Freshwater gammarids, on the other hand, often dominate lotic habitats and shallow stagnant pools/ditches (Meijering, ; Schwartz, ). Compared with notonectids, the predatory impact of gammarids towards larval mosquitoes has been seldom considered (but see Schwartz, ; Roberts, ).…”

“…Freshwater gammarids, on the other hand, often dominate lotic habitats and shallow stagnant pools/ditches (Meijering, ; Schwartz, ). Compared with notonectids, the predatory impact of gammarids towards larval mosquitoes has been seldom considered (but see Schwartz, ; Roberts, ). These two predators were selected because they are numerically dominant in the study area and are representative of different aquatic habitat types (i.e.…”

The influence of a predatory ostracod, Australocypris insularis, on zooplankton abundace and species composition in a saline lake

“…Ostracods have been a dominant feature in Australian saline lakes possibly since the Triassic period (McKenzie, 1981) so the influence of ostracod predation on the zooplankton community in these lakes is not unexpected. The ability of a partially benthic and detritivorous predator to affect densities of pelagic prey has been noted in freshwater systems as well, particularly in shallow and ephemeral ponds (Schwartz, 1992) .…”

“…insularis on live zooplankters range from 0 .8-3 .0 prey/predator/day (based on laboratory flask experiments ; Campbell, 1993) and are similar to rates observed for some pelagic and benthic planktivores in fresh waters (e .g . Confer & Applegate, 1979 ;Herzig & Auer, 1990 ;Schwartz, 1992) . Selective predation by such ostracods could influence the abundances of those zooplankton species that inhabit Australian saline lakes .…”