Modelling the dynamic spatio-temporal response of predators to transient prey patches in the field.

Abstract

The spatio-temporal dynamics of two aphid species (Metopolophium dirhodum and Sitobion avenae) and a generalist predator (Pterostichus melanarius) were observed in a field-scale study using a grid of 256 sampling locations with a 12-m spacing. Using Spatial Analysis by Distance Indices we demonstrate that populations show ephemeral spatial pattern at the field scale. We observed a positive, lagged beetle response to this aphid pattern; conversely, the aphids displayed a negative, lagged response to beetle spatial pattern. Examination of the local structure of the spatio-temporal dynamics revealed a strong response by the beetle population to aphid patches. The temporal structure of spatial associations between the species shows a strong correspondence with those from a conceptual model of predator-prey spatial interaction. The spatially coupled dynamics were sufficiently strong for the predator to have a negative effect on the intrinsic rate of increase of their prey.