Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Forget rainy springs

14.10.2003


Sculpture by Wesley Anderegg, Lompoc, Calif.
Courtesy photo


Previous year’s drought might predict following year’s mosquito population

So you think you know mosquitoes?

Consider the venerable law that rainy weather is the cause of increased mosquito populations.



An ecologist at Washington University in St. Louis says if you believe that, youre all wet.

Jon Chase, Ph.D., assistant professor of biology in Arts & Sciences at Washington University, and his wife Tiffany Knight, Ph.D., a postdoctoral researcher at the University of Florida, have found that the previous years’ drought is the cause of high mosquito populations coming out of wetlands in the following year. This is because some wetlands, which are the home to mosquito larvae, dry during drought years, drastically reducing mosquito predators - from fish to water beetles - and competitor species such as snails, tadpoles, and zooplankton.

This conclusion stands the ecological world on its head and, with more extensive scrutiny, eventually could have implications in prediction and control of diseases like West Nile virus, St. Louis encephalitis and malaria that are all carried by mosquitoes. The study will appear in the November issue of Ecology Letters.

Chase and Knight are now analyzing data from locales across North America to see if their results found in local wetlands translate to larger spatial scales.

"We’re dealing with the ecology of mosquito larvae in wetland food webs and trying to see if this translates to the landscape level," said Chase. "This is important because mosquitoes live in all sorts of habitats besides the ponds, marshes, and swamps that we studied. Consider treeholes, tires and puddles. With the data we have we’re trying to run correlations between precipitation and mosquito density over 20-year and 30-year spans to see how well our hypothesis predicts mosquito abundance. We’ve found that the current year’s precipitation explains almost nothing but the past year’s precipitation explains a lot. "

The team also is looking into disease implications.

"This (disease) is much harder to prove because there is so much epidemiology to take into consideration, for instance the role of intermediate hosts and other complexities," Chase said . "Very few people are looking at these mosquito-borne diseases in a modern ecological context. Most of the work comes from the epidemiological, genomic and/or molecular biology perspectives."

Chase, a community ecologist, and Knight, a population ecologist, came to their conclusion by accident. A pond they had been studying in Pennsylvania dried up during a drought and the next year, after the pond was replenished, mosquito larvae came back like gangbusters. They then surveyed approximately 30 ponds, some permanent but others semi-permanent and temporary. They found few mosquito larvae in permanent ponds but lots of mosquito predators; in ponds that dried up annually mosquito larvae were scarce because of lots of competitor species, zooplankton, snails and tadpoles. Those ponds that were usually full but dried out after a 1999 drought, however, had lots of mosquito larvae and very few predators and competitors because, Chase and Knight reason, those species aren’t adapted to dry spells in these ponds.

The team was able to recreate this natural study by filling tanks with soil and water and stocking them with mosquito larvae and other species found in natural ponds. They gave these artificial ponds three years to allow the ecosystem to form and stabilize, and then slowly drained some of the tanks to simulate a drought. The next year, the mosquito larvae numbers were very large compared with tanks that were drained each year or remained full.

Analyzing data provided by the city of Winnipeg, Canada, Chase and Knight found that drought the previous year is a much better predictor of high mosquito populations than the current year’s rainfall.

Tony Fitzpatrick | WUSTL
Further information:
http://news-info.wustl.edu/tips/page/normal/426.html
http://www.wustl.edu/

More articles from Ecology, The Environment and Conservation:

nachricht Listening in: Acoustic monitoring devices detect illegal hunting and logging
14.12.2017 | Gesellschaft für Ökologie e.V.

nachricht How fires are changing the tundra’s face
12.12.2017 | Gesellschaft für Ökologie e.V.

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>