Can pollen provision mitigate competition interactions between three phytoseiid predators of Tetranychus urticae under future climate change conditions?

Abstract

Biological control can be severely disrupted by hot and dry environmental conditions associated with climate change. These conditions may alter the food web configuration of arthropod communities through their effects on species interactions. They could disrupt the competition between the phytoseiid predators Euseius stipulatus, Neoseiulus californicus, and Phytoseiulus persimilis, which are the key natural enemies of Tetranychus urticae in citrus in Spain. Because the provision of alternative food could compensate for such a situation, we studied in laboratory conditions whether pollen supply could modify competition among these predatory species under different climatic conditions. Our results show that access to high-quality pollen may enhance the performance of E. stipulatus and N. californicus. However, when the phytoseiids considered in our study were forced to compete, pollen provision had contrasting effects depending on the competing pair. Overall, climate change did not affect predation when pollen was available. Predation, though, was lower than expected except when the competing pair was P. persimilis and E. stipulatus. Therefore, pollen provision can partially mitigate the adverse effects of climate change on some of the biological parameters of the three main predators of T. urticae when competing in the system. This has important implications for the future success of biological pest control.