According to the Connecticut Agricultural Experiment Station, the state’s mosquito population has increased 60 percent over the past 20 years.
In a study published Nov. 6 in Scientific Reports, researchers at the stations analyzed annual changes in mosquito biodiversity, abundance, and distribution at 87 trapping sites across the state. Not only did they find that mosquito incidence increased by 60 percent, but they also found that numerous species of mosquitoes have been introduced into the state over the past 20 years.
The species that showed population growth in the state shared some similar traits, including a reliance on permanent (or semi-permanent) waters and a preference for mammalian blood. The researchers also found evidence that many species of mosquitoes migrate north and may respond to changing environmental factors.
“Changes in land and climate offer opportunistic insects – like mosquitoes – unique opportunities to take advantage of the many habitats we create for them,” said Dr. Joseph McMillan, co-author of the study, in a press release. “As humans continue to change the environment, mosquitoes are poised to benefit from those changes.”
McMillan is also a postdoctoral fellow at the agricultural research station.
The station captures mosquitoes in 87 communities across Connecticut as part of the nationwide mosquito surveillance program. Mosquitoes are tested for the West Nile and other mosquito-borne viruses between June and October.
This year, at least 143 mosquitoes tested positive for West Nile Virus and two tested positive for Eastern Equine Encephalitis. There have been at least four cases of West Nile virus in humans in Connecticut that year.
“This study shows the value of long-term monitoring data,” said Dr. Philip Armstrong, study co-author and medical entomologist at the experimental station, in the press release. “It clearly shows that mosquitoes are on the rise in Connecticut and provides a basis for monitoring future population changes and range expansions that can be expected under the impact of climate change.”