Pollen supply promotes, but high temperatures demote, predatory mite abundance in avocado orchards

A biological control strategy aimed at enhancing the performance in the field of two predatory mites that are natural enemies of an invasive pest of avocado orchards was applied during two consecutive years. Unexpected poor pest control led us to analyse additional factors involved in the dynamics of the community such as summer environmental conditions, which were very hot and dry. Non-linear regressions considering biotic and abiotic effects suggested that high temperatures during the second half of the summer were central to predator/prey population dynamics. Harsh environmental conditions were therefore a direct cause of biological control disruption. We believe that, in the future, the success of biological control strategies will be limited by the natural enemy's capacity to respond adaptatively to rapid climate changes, and that research aimed at evaluating the evolutionary potential of natural enemies to rapid climate change should be the focus of future investigations. (C) 2012 Elsevier B.V. All rights reserved.