Impact of Leaf Detritus Species on Mosquito Ecology in Artificial Container Habitats

EPA Grant Number: F13F11066
Title: Impact of Leaf Detritus Species on Mosquito Ecology in Artificial Container Habitats
Investigators: Gardner, Allison
Institution: University of Illinois at Urbana-Champaign
EPA Project Officer: Lee, Sonja
Project Period: August 25, 2014 through August 25, 2016
Project Amount: $84,000
RFA: STAR Graduate Fellowships (2013) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Fellowship - Entomology

Objective:

One of the most important predictors of human risk of exposure to mosquito-borne pathogens is the density of mosquito vectors. The abundance and distribution of container-breeding mosquitoes is determined in large part by terrestrial plant-based detritus, which supports the microbial flora on which larval mosquitoes feed. This research investigates ecological pathways by which leaf detritus of different plant species alter aquatic habitat quality and attractiveness for an important epidemic vector of West Nile virus, Culex pipiens (Diptera: Culicidae), and explores the potential to apply these findings to develop environmentally safe and sustainable mosquito control strategies.

Approach:

Leaf detritus from different terrestrial plant species likely mediates aquatic habitat quality and attractiveness by two mechanisms: variation in nutritional quality and release of phytochemicals during decomposition. This study will test these alternate mechanisms by measuring the microbial composition of infusions of each of six common leaf species using quantitative PCR and the phytochemical content of the same species using gas chromatography. It also is likely that inputs of different leaf detritus species in closed aquatic habitats alters mosquito production in these environments, and combining inputs of attractive leaf species with conventional insecticides may result in a novel “attract-and-kill” mosquito control strategy. A field experiment will test these predictions in roadside stormwater catch basins, which are important aquatic habitats for Cx. pipiens in the urban ecosystem.

Expected Results:

Two years of previous data indicate that the effect of leaf detritus on habitat selection and mosquito development is variable; in particular, an exotic and invasive plant (honeysuckle, Lonicera maackii) supports high oviposition and adult mosquito emergence rates, whereas a native species (blackberry, Rubus allegheniensis) is highly attractive but deleterious for the juvenile development of Cx. pipiens. It is expected that honeysuckle enables high mosquito production due to its nutritional quality, while blackberry leaves contain toxic phytochemicals (e.g., tannins). Provisioning storm water catch basins with either blackberry leaf detritus or honeysuckle combined with a conventional insecticide is expected to yield increased oviposition and equal emergence rates compared to the application of the insecticide alone, validating use of the attractive compounds contained in blackberry and honeysuckle leaves as supplements to insecticides for attract-and-kill mosquito control.

Potential to Further Environmental/Human Health Protection

Due to a lack of vaccines for most mosquito-borne viruses, vector control is the most effective and often the only viable option for reducing the risk of human exposure. Current mosquito control strategies rely heavily on the use of synthetic insecticides, but the evolution of insecticide resistance in vector species and environmental safety concerns have contributed to a need for sustainable alternatives for mosquito abatement. By examining ecological drivers of mosquito production, this study has the potential to discover a novel, inexpensive and effective vector-control method with minimal non-target effects and reduced potential to select for insecticide resistance.

Supplemental Keywords:

community ecology, integrated vector management, mosquitoes

Progress and Final Reports:

  • 2015
  • Final