skeeter
There is perhaps nothing more annoying than mosquitoes in the summer with their buzzing and biting. Aside from being a nuisance, the insects can also be disease carriers, capable of infecting humans as well as animals.
With that said, methods to rid our backyards of the pesky creatures have come and gone, including the extensive use of chemicals in various forms.
After the hot, dry summer experienced across the country promoted the spread of West Nile Virus in many states, intense sprayings took place in many areas — sometimes even by aerial dispersal — to get rid of the pest. But the use of such insecticides comes with its own concerns.
Research at the University of Kentucky is examining the possibility of ridding certain mosquitoes without the use of any chemicals.
Stephen Dobson, professor of medical and veterinary entomology, said the project essentially renders mosquitoes sterile by infecting them with a bacterium that would cause that sterilization.
“I wouldn’t call it a replacement. I think there are situations where insecticides are going to be the best idea, but we want to provide some non-insecticidal tools for controlling mosquitoes and the diseases they carry,” he said.
The idea of controlling insects with biological agents is not new, and this research, developed at UK and funded through the National Institutes of Health and a grant from the Bill and Melinda Gates Foundation, has been something Dobson has worked on since coming to the university in 1998. He said the institute has made an incredible investment in equipment that has allowed this research to be conducted. The eventual goal is to use this technology against multiple species of mosquitoes.
“There are lots of different types of mosquitoes in your backyard. Some are active at night, some are active during the daytime, and ultimately we would like to target most if not all of those,” Dobson said. “But right now, we’re focusing on a single mosquito species called the Asian Tiger mosquito.”
That particular insect is on the list of the most important invasive species in the United States, having been introduced here in 1985 from Southeast Asia. It is known for its aggressive human-biting behavior and has the ability to carry many viruses including West Nile, according to information from the USDA.
“It is in every county in Kentucky, and it’s really spreading on a continental scale,” said Dobson. “It carries things that affect human health as well as animal health.”
While it has taken years of serious technical research to perfect this tactic, the idea is simplistic in nature. The hard part was getting the “Eve” mosquito injected with the naturally occurring bacterium, which is passed on to its offspring. For the male offspring, they can still mate, but the sterilizing bacterium is transmitted to the female. Once this process has occurred enough, the mosquito population will eventually be exterminated in a very natural way.
Dobson said it’s important to note that female mosquitoes are the ones that bite, due to the fact that they need the protein in blood in order to reproduce.
‘That’s one of the key points of our technology. Since males don’t do any harm, they are actually pollinators; we can release our males, which will serve to sterilize the females,” he said.
This scenario is much more acceptable than releasing the biting females, added Dobson. Basically, all the males will do is pollinate flowers and mate with the unsuspecting females.
The research thus far has proven successful in controlled caged environments. The next step is to take the research into the field — or backyard, as it may be. Dobson warned that just because mosquitoes might be eliminated in one neighborhood, that might not necessarily be the case in adjoining neighborhoods.
The males have to be continually released, much the same way as an exterminator would come back for continuing insecticide applications.
“This is a biological pesticide, and instead of spraying a chemical, we’re releasing males. We are going to have to keep doing that, let’s say weekly, until they are gone,” said Dobson. “When you stop releasing the males, presumably, and someone from another neighborhood reintroduces the mosquitoes, over time they come back. But if you continue to do the releases, you can keep the mosquitoes out.”
Educating the public will be a key part of the success of the project, Dobson said. Most people see red flags with the idea of “introduced bacterium.” Dobson emphasized that the bacterium used in this case is likely already in 65 percent of other species found in any given area.
He also pointed out that EPA approval has to be received first before any field tests can be conducted, to make sure it is safe to release the mosquitoes. Experiments have been conducted to answer any questions as to the safety aspect — all with positive results. That has included deducing the fact that there is little risk of disrupting the ecosystem by eliminating mosquitoes.
“This Asian Tiger mosquito is an invasive pest and did not occur in the United States before 1985, so by removing it from your neighborhood, we’re actually going back to a more natural state,” Dobson said. “The current insecticides we have don’t work against this mosquito, so we need these additional tools.”