Spatial dynamics and cross-correlation in a transient predator-prey system

1. We examined spatiotemporal data in a transient, seasonal system involving a specialist predatory beetle, Carcinops pumilio (Erichson), and its prey, larval Musca domestica L. 2. Prior to beetle colonization, larval fly populations were highly spatially structured, but as adult predatory beetles immigrated and colonized the field, the beetles became increasingly clustered at local spatial scales, causing spatial decorrelation in the dynamics of their prey. Larval flies appeared to regain local clustering as beetle abundance approached a carrying capacity with the prey population. 3. During exponential population growth, beetles were generally strongly negatively cross-correlated with their prey at local spatial scales. 4. We were able to simulate these spatially-extended interactions in a predator-prey coupled map lattice model. We used this model to investigate the effects of global and local prey reproduction, in the presence and absence of global stochasticity, on predator and prey spatial structuring and cross-correlation. 5. The work shows in a uniquely detailed fashion how the transition from eruptive pest abundance to regulation by a specialist predator is associated with a transition in spatial structure.