 |
Search Sponsored
|
|
| 9/20/2006 4:00:00 AM | Email this article • Print this article
Comment on this article |  |
|
Provided photo
Traps keep track of mosquito populations on the Peninsula, where 596 were captured on one recent summer evening. |
|
Peninsula mosquitoes have a 'buzzy' summer
By Russ Lewis
Friends of the Wildlife Refuge
PENINSULA - It was another typical year for the annual presence of mosquitoes around Willapa Bay and the Peninsula area during 2006.
The onslaught of these biting insect pests first begin their biting and buzzing annoyance to humans by early May and then rapidly build up to peak numbers during early June.
It is not advisable to don your hiking shorts for a leisurely walk out on Leadbetter Point at that time. These are very aggressive mosquitoes as they fly straight in to commence drilling for a meal on exposed skin or even through light fabrics such as a T-shirt. Five hundred ninty-six mosquitoes were captured during one night of trapping out at Leadbetter during the second week of this past June. The trap canister was audibly humming while being packed out from the woods for processing. This trapping is being conducted to detect if west Nile virus is present in any of our local mosquito species. There is good news to report out at Leadbetter Point lately; mosquito season is now rapidly winding down for this summer as September arrives and so far, west Nile virus has not been detected. Noteworthy is the fact that none were caught during trapping last September.
Mosquito biology is straightforward. They are members of the true fly family, order Diptera. They undergo four separate and different stages during their life cycle. It begins in the following order with the egg, larva, pupa and adult stages.
The minute eggs are sticky and are layed in groupings on the surfaces of any quiet fresh water sources in masses of hundred or more eggs. The eggs take on the appearance of a tiny raft afloat.
Larva soon hatch and begin to actively feed on microorganisms. They will molt four separate times as they increase in size before eventually becoming pupas.
The pupa stage is a non-feeding resting stage whereas the adult mosquito emerges in a couple of days. The females' hunt for blood now begins. This whole cycle can take as little as two weeks to complete. Only the female mosquito possess the specialized mouth structure called a proboscis designed to pierce the skin of a warm-blooded mammal. She feeds on blood for life giving proteins. The males have a totally different mouth structure that enables them to only feed on flower pollen for nutrition.
There are approximately 2,500 different species of mosquitoes existing worldwide, of which 150 are found in the United States. Mosquitoes can carry diseases such as the malaria parasite and West Nile virus. Any mosquito species determined to carry such diseases are classified as a vector species. There are 58 known mosquito vector species in the United States that are identified as potential carriers of West Nile virus, while only 19 out of these 58 have been identified in Washington State alone. This does not mean West Nile virus is present at this time or that all of Washington's 19 known mosquito vector species are found in Pacific County. However, there could be some vector mosquito species present that are capable of transmitting the virus. To date the virus has not yet been determined to be present in any of our identified mosquito species known to reside in our area.
Monitoring of mosquito species is an important tool currently being implemented right here throughout Pacific County in the determination and testing for West Nile virus by the Washington State Department of Health-Office of Environmental Health and Safety. Mosquito traps are being currently set out in different locations of suitable mosquito habitat around Willapa Bay under the supervision of wildlife biologist Marie Fernandez of the Willapa National Wildlife Refuge. John Schroeder and Russ Lewis are volunteers who trap the mosquitoes for Marie who in turn coordinates the results with personnel from Washington State Department of Health.
Mosquitoes are trapped once every two weeks. The trap consists of a dry ice-filled canister with a net trap attached to the underside of the canister. It is attached to a tree limb about six feet above the ground and kept in operation overnight. There is a small electric fan located between the canister and net trap that blows carbon dioxide downward from the canisters dissipating dry ice. The carbon dioxide filters through the net trap. Mosquitoes are attracted by carbon dioxide and enter the net trap. It is a one-way trip. They are collected and eventually sent off for species identification and for the presence of the virus.
For more information on West Nile virus contact The Department of Health West Nile virus Web site (www.dohwa.gov/WNV) and toll free information line (1-866-78VIRUS) which will have the latest information on bird, horse and human cases in the state. Information on mosquito biology can be found on website (www.mosquito.org/mosquito.htm)
(www.friendsofwillaparefuge.org)
|
Article Comment Submission Form
|
|
|
|
