Picture yourself in a room filled with 400,000 mosquitoes.

Now picture them dead.

No buzzing, no biting, no blood-feeding. No infected mosquitoes, no transmitted diseases, no serial killers.

This is the global mosquito collection at the Bohart Museum of Entomology at the University of California, Davis, now being preserved or curated under a three-year National Science Foundation grant.

Bohart Museum director and principal investigator Lynn Kimsey, an entomology professor at UC Davis, said the massive project includes six major individual collections as well as "new donations that come in continually."

World-class mosquito systematist Tom Zavortink, a retired professor of biology at the University of San Francisco and now a curator at Bohart, donated one of the largest collections, totaling 44,642 specimens.

Zavortink leads a group of Bohart scientists in identifying and labeling the specimens, pinning the adults, and either slide-mounting or alcohol-preserving the larvae and pupae. He works with Kimsey, Bohart museum scientist Ken Lorenzen and an influx of graduate and undergraduate students.

"Tom is one of only two or three systematists in the United States skilled at identifying exotic mosquito species," Kimsey said. Zavortink's credits include recipient of the international John N. Belkin Award in 1984 for furthering mosquito systematics or classification.

Worldwide, more than 3200 species exist, including Anopheles mosquitoes, which transmit malaria, and Culex mosquitoes, which transmit West Nile virus and viral encephalitis. Some 174 species are known in the United States.

"When this is all sorted out, it will be the second best collection in this country and the New World," Zavortink said. That's second only to Smithsonian Institution, Natural History National Museum of Natural History, in Washington, D.C.

Zavortink collected most of his specimens from Central and South America (Peru, Venezuela, Panama, Costa Rica, Brazil and Argentina), Asia (Malaysia and Singapore) and Africa (Central African Republic, South Africa, Kenya, Senegal, Zambia and the Ivory Coast).

They include 11 species from the new subgenus Zavortinkius of the genus Aedes (tiger mosquito), isolated from the Afrotropical region.

Five other scientists donated large collections:

. Richard Bohart, UC Davis emeritus professor of entomology (for whom the Bohart Museum is named), collected thousands of mosquitoes in the western United States and the Pacific Islands during World War II. "This is of great value to researchers who wish to estimate the original distributions of mosquitoes in this region," Kimsey noted.
. Ralph Barr of UCLA's School of Public Health, who died in 1995, contributed 41,187 specimens from Asia (Malaysia, Singapore, Thailand and Japan) and the upper Midwest.
. Lewis Nielsen of the University of Utah donated 78,005 specimens, including large amounts of reared material of Ochlerotatus, from the intermountain western United States. Ochlerotatus is an important vector of encephalitis viruses and also transmits West Nile virus.
. Bruce Eldridge, UC Davis emeritus professor of entomology and former director of the UC Mosquito Research Program, contributed 10,626 "snow pool" mosquitoes, collected mainly in the Sierra Nevada and Cascade ranges in California, as well as in the mountainous areas of Nevada, Oregon and Washington.
. William Reeves (1916-2004) of UC Berkeley's School of Public Health and a frequent visitor to UC Davis, donated thousands of specimens from his expeditions throughout the world.

Eldridge's collection includes many obtained on annual excursions with Reeves. Eldridge also stalked mosquitoes with his then post-graduate research students Gregory Lanzaro (now director of the UC Mosquito Research Program and the UC Davis Center for Vectorborne Diseases) and Steve Schutz (now scientific programs manager for the Contra Costa Mosquito and Vector Control District); and graduate students John Gimnig and Anne Fritz.

"All of this was supported by an NIH (National Institutes of Health) grant I had at the time to study California serogroup viruses," Eldridge said.

Kimsey, Zavortink and Lorenzen are addressing many curator issues. "First, many specimens are from reared series linked only by code numbers and many lack any locality information other than field numbers, which refer to field books," Kimsey said. "These specimens must be properly labeled by using the information found in the records and field books that accompany the collections."

"Second, some pinned specimens are mounted using corrosive cork blocks, and need to be remounted using proper pinning media. Finally, all of the alcohol-preserved specimens are in glass vials with decaying rubber or neoprene stoppers and need to be transferred to more appropriate alcohol vials."

The value of the collection is immeasurable, Kimsey said. Mosquitoes are the most common vectors of pathogens worldwide, killing some 3 million people a year. Mosquito-borne diseases include malaria, West Nile virus, several forms of encephalitis (Western equine, eastern equine, St. Louis and Japanese encephalitis) yellow fever, dengue fever and Rift Valley fever, and dog heartworm.

Mosquito-borne diseases once found only in Africa are now spreading throughout the Western hemisphere. West Nile virus (WNV), first isolated in Uganda in 1937, was discovered in New York in 1999 and in California in 2002. The Centers for Disease Control and Prevention (CDC) tallied 3000 WNV illnesses in the United States last year, and 119 deaths, including 19 in California. A massive outbreak of dengue fever in Puerto Rico sickened 9000 in 1998.

"Residents, tourists and military personnel are at risk of disease wherever mosquitoes and their breeding grounds are common," Kimsey said.

She linked emerging infectious diseases to the global economy. Exotic mosquitoes often arrive at U. S. ports via infected birds and in water-filled containers. In 2001, Los Angeles port inspectors opened a shipment of "lucky bamboo" (Dracaena sanderiana) from China and discovered the larvae of the Asian tiger mosquito, Aedes albopictus.

As for how the West Nile virus hitched a ride to the United States, Kimsey, Zavortink and Lorenzen suspect it arrived via imported birds or through the "illegal bird trade." Said Kimsey: "The birds are always getting loose in our ports." Or, WNV may have arrived via "infected humans."

The threat of exotic diseases and epidemics is where the Bohart Museum collection, housed at 1124 Academic Surge on the UC Davis campus, comes in. The first step in controlling a mosquito is to identify it: the egg, larva, pupa and adult. It's all about "know your enemy" and its biology.

"Historically, vector identifications have been questionable at best or worse, incorrect," Zavortink said.

Kimsey said well-curated collections also can lead to important scientific studies, such as the development of vaccines or treatment through chemotherapy and the prediction of the roles of medically important mosquitoes.
UC Davis has long served as the West Coast center for the study of mosquito-borne diseases. In the 1950s, entomologists Richard Bohart and Robert Washino, now both emeritus professors, began publishing scientific papers about mosquito systematics. They co-authored three editions of Mosquitoes of California, dealing with taxonomy and keys for 47 species, diseases, and zoogeography.

UC Davis is the home of the statewide UC Mosquito Research Program and the multidiscipline Center for Vectorborne Diseases, both directed by medical entomologist and professor Gregory Lanzaro. Among the other world-class entomologists at UC Davis who supported the 2004 grant and stand to benefit from the collection: Thomas Scott, Anthony Cornel, Sharon Lawler and Robert Kimsey, a forensic entomologist.

The Bohart Museum Web site is http://bohart.ucdavis.edu.

For photos of the project, see http://www.ucmrp.ucdavis.edu/news/bohartmosquitoes.html.