Predation of mosquitos by odonates in a tropical urban environment: insights from functional response and field mesocosm experiments

Abstract

Mosquito borne diseases (e.g., dengue fever, Zika fever, chikungunya fever) are a recurring problem worldwide. Using the natural predators of mosquitoes, such as odonates (dragonflies and damselflies), provides an alternative, more sustainable approach towards vector control. We assessed the biological control potential of the larvae of three common urban odonates (Crocothemis servilia, Ischnura senegalensis, Orthetrum sabina) using laboratory-based functional response and field-based mesocosm experiments. Functional response experiments using fourth instar Aedes albopictus mosquito larvae as prey revealed Type II functional responses in all three odonate species, highlighting their predatory efficiencies at low prey densities and demonstrating that urban odonates can consume substantial numbers of mosquito larvae (up to 44 per day) under experimental conditions. Complementary field-based experiments, however, showed little impact of odonate larvae predation on the overall composition of naturally colonizing aquatic macroinvertebrate communities, but revealed substantial size-selective predation by odonate larvae on mosquito larvae. Our results provide the first assessment of the predation efficiencies of urban odonate larvae, and highlight their potential as biological control agents of mosquitoes and other aquatic insect pests in highly modified urban landscapes.