Mosquitoes in Food Webs and Meta-communities

In addition to being a general nuisance to humans through their biting activities, mosquitoes are vectors for several important human diseases, such as Malaria, Dengue Fever, Yellow Fever and West Nile Virus, as well as diseases of domesticated animals, such as Equine Encephalitis and Canine Heartworm .  Although a great deal of research is focused on understanding the molecular biology of mosquitoes and their role as disease vectors, basic mosquito ecology is often poorly integrated into these studies.  In addition, large amounts of money are spent on mosquito surveillance, research, and control.  Nevertheless, our ability to predict mosquito abundance is limited to very short time scales, although longer-term predictive ability, such as year-to-year variation in abundance, would provide obvious advantages.  This research is in collaboration with Tiffany Knight, and is an outgrowth of the research in wetlands discussed above. 

In eastern North America , two of the most important mosquito species are Anopheles quadrimaculatus and Culex pipiens, which readily lay eggs in, and emerge from wetlands of all types.  Wetlands can be divided into three classes—temporary, permanent, and semi-permanent—based on their probability of retaining standing water throughout the year.  Permanent wetlands have dense predator populations, including fish and many insects, and can thus control mosquito densities.  Temporary wetlands are have dense mosquito competitors, which can adapt to the predictable yearly drying of these wetlands (e.g., zooplankton with resting eggs), and can thus control mosquito densities    Semi-permanent wetlands periodically dry when precipitation and the water table are particularly low.  In years prior to a drying event, we predict that predators will be common and mosquito densities will be low.  In years following a drying event, we predict that both efficient mosquito predators and mosquito competitors will be rare, since neither group of species are well adapted to drying events.  Thus, while during normal years, mosquito abundance should be low in semi-permanent wetlands, we predict that mosquito outbreaks will occur in years following a drying event because larvae are released from both competition and predation.  Although we are still in the midst of testing these hypotheses, we have found support for this basic prediction both in surveys of natural ponds and experimental cattle tanks where we experimentally induced a drought event.  In addition, we have begun analyzing data from mosquito densities through time provided to us from a variety of Mosquito Control Districts.  Further, we will explore how this effect may translate to patterns of year-to-year variation in human diseases vectored by mosquitoes. 

The mosquitoes have also piqued some wacky creativity.  After a long day in the field, a poem about Harvey the Larvae emerged.  Check it out here.

Permanent Pond

Temporary Pond

Mosquito art from www.Lakeview-Museum.org

Dried Tank