Discovery and exploitation of a natural ecological trap for a mosquito disease vector

Authors: GARDNER, ALLISON - University Of Maine; Muturi, Ephantus; ALLAN, BRIAN - University Of Illinois

Submitted to: Proceedings of the Royal Society. B. Biological Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2018
Publication Date: 11/22/2018
Citation: Gardner, A.M., Muturi, E.J., Allan, B.F. 2018. Discovery and exploitation of a natural ecological trap for a mosquito disease vector. Proceedings of the Royal Society B. http://dx.doi.org/10.1098/rspb.2018.1962.
DOI: https://doi.org/10.1098/rspb.2018.1962

Interpretive Summary: West Nile virus is the most prevalent mosquito-borne pathogen in the U.S., and due to a lack of vaccines, mosquito control is the only viable strategy to prevent transmission. Stormwater catch basins provide an important source of vector mosquitoes and are common targets for insecticide-based mosquito abatement efforts, but evolution of insecticide resistance, non-target effects, and concerns regarding the safety of insecticides limit insecticides’ effectiveness and widespread use. Our study demonstrates that manipulation of leaf litter in stormwater infrastructure can alter mosquito production in these habitats, increasing their attractiveness for oviposition while inhibiting development of larvae. Our findings suggest the potential for an effective new ‘attract-and-kill’ complement or alternative to conventional insecticides for juvenile mosquito control in man-made aquatic habitats.

Technical Abstract: Ecological traps occur due to a mismatch between a habitat’s attractiveness and quality, wherein organisms show reference for low-quality habitats over other available high-quality habitats. Our previous research identified leaf litter from common blackberry (Rubus allegheniensis) as a natural ecological trap for an important vector for West Nile virus (Culex pipiens), attracting mosquitoes to oviposit in habitats deleterious to the survival of their larvae. Here we demonstrate that manipulation of leaf litter in stormwater catch basins, an important source of disease vector mosquitoes in urban environments, can increase Cx. pipiens oviposition but reduce survival. In a series of experiments designed to elucidate the mechanisms that explain the attractive and lethal properties of this native plant, behavioural bioassays suggest that oviposition site selection by Cx. pipiens is mediated primarily by chemical cues as leaves decompose. However, we also show that juvenile mosquito survival is mainly related to the suitability of the bacterial community in the aquatic habitat for mosquito nutritional needs, which does not appear to create a cue that influences oviposition choice. This mismatch between oviposition cues and drivers of larval habitat quality may account for the ecological trap phenomenon detected in this study. Our findings provide new insights into potential mechanistic pathways by which ecological traps may occur in nature and proof-of-concept for a new ‘attract-and-kill’ tool for mosquito control.