Baltimore Ecosystem Study Institute of Ecosystem Studies

2013 BES Annual Meeting Presentation and Poster Abstracts

Shifting composition of mosquito species and potential disease risk along an urban to rural gradient.
Goodman, Heather
Co-Authors: Heather Goodman,ScM and Shannon Ladeau, PhD

Baltimore County has seen human incidence of West Nile virus (WNV) each year since the first human case in Maryland in 2001. This mosquito vectored disease has a complex transmission cycle involving several mosquito species, avian hosts, and the overlap of human, bird, and mosquito habitats. One focus of this study is to evaluate differences in mosquito species composition and population peaks along a gradient from high-density urban habitat to rural, forested habitat. Ovitraps were deployed over four years during the mosquito season (20 weeks) at ten locations dispersed from Baltimore City out to rural Baltimore County. Each week all immature mosquitoes collected in the ovitraps were enumerated and identified to species. These data demonstrate considerable variation in the timing and magnitude of population abundances across the four years, which are related to inter-annual differences in weather but also may be due to more subtle shifts in the composition of invasive species. As expected, the more diverse mosquito communities in rural, forested sites have relatively even population abundance across species. Although fewer mosquito species were found at urban sites, these communities were dominated by the invasive and human biting mosquitoes Ae. albopictus, Ae. aegypti, Culex pipien, and more recently Ae. japonicus. In addition, mosquito vector species sampled from urban habitats reached a higher peak abundance and did so earlier on in the season. Future bloodmeal analysis and arboviral testing will explore the role of mosquito species found in local urban habitats in disease transmission and monitor any shifts in feeding behaviors.