Mechanisms of intra-and interspecific interference between larval stoneflies.

摘要: Behavior of focal individuals two potentially competing sympatric stonefly species, Megarcys signata and Kogotus modestus (Perlodidae), was videotaped in flow-through plexiglass arenas placed the East River, Gunnison County, Colorado. Focal were observed alone pairs with conspecifics allospecifics at four prey (Baetis bicaudatus, Baetidae, Ephemeroptera) densities to determine whether competitors resource levels affected capture rates. Presence conspecific or allospecific reduced rates, especially for Kogotus, smaller due a significant decline predator-prey encounter rates present. This competitive effect not lowest highest very low high respectively. Thus, interference feeding only intermediate densities. Competitors had no on probability attacks per success attack. Within each species effects intra-and interspecific similar, even though behavioral responses by both stoneflies encounters more frequent than conspecifics. showed response other stoneflies, maintaining those over all Further, male which are sex, responded frequently interactions did females. These data consistent hypothesis that asymmetrical Megarcys, larger being superior competitor.