Path and Spatial Learning in a Stonefly Nymph

The ability of an aquatic invertebrate to learn the location of a preferred resource (a group of stones that provide shelter from predators), was assessed. In the first experiment, the stonefly Paragnetina media displayed a capacity for path learning. During successive trials, stoneflies crawled between starting points and substrate assemblages (stone groupings) more quickly when both positions were fixed, than did stoneflies in aquaria in which the starting points were fixed but substrate positions were not. In the second experiment, P. media demonstrated an ability to learn to locate stone assemblages when released at variable points in aquaria (i.e., spatial learning).(...) We demonstrate that stoneflies that had learned the location of shelters experienced significantly fewer attacks from rainbow trout than naive individuals