Lethal (consumption) and nonlethal effects of predation can impact phenotypic traits of potential prey that elude capture. However, less attention has focused on how mosquito prey responds to lethal and nonlethal effects of multiple stressors experienced during the juvenile stage. Insect growth regulators (IGR) used for mosquito control inhibit the emergence of adult mosquitoes, but do not kill the larvae. This mechanism of action has potential to act in conjunction with other sources of natural mortality, such as predators to affect prey populations. Here, we conducted a series of experimental manipulations to assess lethal and nonlethal effects of a combination of IGR pyriproxyfen and predatory mosquito Toxorhynchites rutilus on invasive prey mosquito Aedes aegypti.
Results/Conclusions
Combined effects of IGR pyriproxyfen and predator achieved lower recruitment to the adult stage than exposure to pyriproxyfen or predator alone. Exposure to pyriproxyfen, T. rutilus, or their combination during the juvenile stage shortened the lifespan of female and male adults, whereas control and numerical reduction treatments that mimicked daily mortality of predation lengthened lifespan. Our findings show strong lethal and nonlethal effects of IGR pyriproxyfen and predation on mosquito Ae. aegypti. These results suggest an unexpected benefit of the use of an IGR when combined with a natural predator of mosquitoes that may be exploited to improve mosquito control strategies to reduce the risk of disease transmission.