Notonecta exhibit threat-sensitive, predator-induced dispersal.
Dispersal is a central process determining community structure in heterogeneous landscapes, and species interactions within habitats may be a major determinant of dispersal. Although the effects of species interactions on dispersal within habitats have been well studied, how species interactions affect the movement of individuals between habitats in a landscape has received less attention. We conducted two experiments to assess the extent to which predation risk affects dispersal from an aquatic habitat by a flight-capable semi-aquatic insect (Notonecta undulata). Exposure to non-lethal (caged) fish fed conspecifics increased dispersal rates in N. undulata. Moreover, dispersal rate was positively correlated with the level of risk imposed by the fish; the greater the number of notonectids consumed by the caged fish, the greater the dispersal rate from the habitat. These results suggest that risk within a habitat can affect dispersal among habitats in a landscape and thus affect community structure on a much greater scale than the direct effect of predation itself.
McCauley
Shannon J
SJ
Ecology & Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada. shannon.mccauley@utoronto.ca
Rowe
Locke
L
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D003710:Demography; D017753:Ecosystem; D005399:Fishes / Q000502:physiology; D020062:Heteroptera / Q000502:physiology*; D009864:Ontario; D011156:Population Density; D011235:Predatory Behavior / Q000502:physiology; D012306:Risk