Host-plant mediated effects on group cohesion and mobility in a nomadic gregarious caterpillar

摘要: Gregarious animals often live in larger groups food-rich environments. We compare cohesion and mobility of forest tent caterpillar (Malacosoma disstria) on high-quality (trembling aspen, Populus tremuloides) low-quality (sugar maple, Acer saccharum) host trees. Following pheromone trails allows caterpillars to maintain group cohesion, but can cause become trapped poor-quality food sources. Trail-following decreases food-deprived individuals. combine laboratory field experiments show that this nutritionally mediated balance between trail fidelity exploration generates fission-fusion dynamics, leading increased smaller sizes poorer quality hosts. Indeed, feeding maple spent more time locomotion, split into groups, switched site frequently traveled farther when compared those aspen. These dynamics be explained as an emergent property individual responses conspecifics: Individuals drift apart contexts where cues from conspecifics are weakened. Increased appears adaptive response improves the chances relocating a superior source, lower size likely thermoregulation increases predation. Finally, we not only control spatial distribution individuals tree, they also linked considerable differences growth mortality therefore play important role population dynamics. Many gregarious up is scarce. In many species, behaviors by which members stay together follow each other well-understood; how then do these respond changing conditions? particular, does hunger drive decreased availability? colonies good- plants. use move around together, hungry, tend leave trails. plant mobile (presumably discovering better source), groups—a side effect possibly exposes them greater risks.