Amphibian predation on larval mosquitoes

Abstract

Mosquitoes ( Culex pipiens L., 1758) are important vectors for diseases of both wildlife and humans. Understanding how natural factors influence mosquito abundance may provide insights into the ecology of various diseases, as well as solutions to controlling disease vectors. One of the natural factors regulating mosquito distributions and population sizes is predation. A poorly understood source of natural mosquito predation is amphibians. We determined the mosquito consumption capability of two amphibians, adult Red-spotted Newts ( Notophthalmus viridescens viridescens (Rafinesque, 1820)) and larval Mole Salamanders ( Ambystoma talpoideum (Holbrook, 1838)). We also compared mosquito consumption of eastern mosquitofish ( Gambusia holbrooki Girard, 1859), a known predator of mosquitoes, and A. talpoideum. Both salamander species were capable of consuming large numbers of mosquito larvae per day (least-square means ± 1 SE = 439 ± 20 and 316 ± 35 mosquitoes/day consumed by A. talpoideum and N. v. viridescens, respectively). In A. talpoideum, mosquito consumption scaled with body size, with the largest individual (4.4 g) ingesting 902 mosquitoes in 1 day. Gambusia holbrooki consumed 3.5× more mosquitoes during a 24 h feeding trial than similar-sized A. talpoideum. Our findings suggest that amphibians could have a substantial impact on mosquito larvae abundance, especially considering that amphibians can reach densities of up to 500 000 individuals/ha. Furthermore, we hypothesize that introduction of G. holbrooki could reduce abundances of native mosquito predators (e.g., salamanders) indirectly, through competition for invertebrate prey.