Mosquito Ecology and Mosquito Testing

mosquito biting

Mosquitoes breed anywhere there is standing water (water that is not moving) and only require a small amount of water to reproduce. This means that rural as well as urban areas in Maine are considered mosquito habitat.

What kinds of mosquitoes am I likely to find in Maine?

  • Maine has over 45 different species of mosquitoes. [1]
  • Over half of the species found in Maine can carry the germs that cause illness, but not all of these species bite humans. [2, 3, 4, 5]

In what habitats are mosquitoes typically found?

  • Different types of mosquitoes prefer different types of habitats. Some mosquitoes, such as the Aedes mosquitoes, like wetlands and forested areas. [3] Other mosquitoes, such as Culex pipiens, like urban and suburban habitats.  [6, 7, 8]
  • All mosquitoes require standing water (water that is not moving) for breeding. In general, rivers and fast-flowing streams are not a place where people will find mosquito larvae.
  • You can reduce standing water around your home which can help reduce the potential for mosquitoes.
resting box
Resting Box (courtesty of Kathy Murray)

When am I likely to find mosquitoes?

  • The mosquito species found in Maine are most active from dusk until dawn. [9, 10] Other areas of the country have mosquito species that are active during the day.
  • Mosquitoes are not strong flyers, so they are usually less active when it is windy.

Are pools of mosquitoes tested for mosquito-borne diseases in Maine?

  • Yes. The State of Maine sponsors mosquito testing for EEE and WNV in areas of historical significance, such as where positive results occurred in the past. [11]
  • Any town interested in submitting mosquitoes for testing can contact Maine CDC's disease reporting hotline at 1-800-821-5821 or by email at

What do mosquito traps look like?

Generally, three kinds of traps are used regularly in Maine.

  • Resting Boxes
    • These traps are black plastic boxes (12"x12"x12") that are used to trap mosquitoes associated with EEE. These are placed near wetlands for the season and sampled weekly.
  • Carbon Dioxide (CO2)/Light Traps
    • CO2/light trap
      Carbon Dioxide (CO2)/Light Trap
      These traps look like a cooler with a small motor and battery attached and are usually found hanging from a tree. These are used to survey a wide range of mosquitoes and use dry ice as an attractant. Dry ice gives off gas as a white mist from the cooler. CO2/light traps are hung late afternoon and retrieved the following morning.
  • Black Gravid Traps
    • These traps look like black buckets and are being used in urban areas and sampled weekly. These traps are being used to look for the mosquitoes that have the potential to carry Zika virus.

What do I do if I find a mosquito trap?

  • Please do not touch a mosquito trap if you find one, unless it is preventing movement.
  • Please call the Maine Medical Center Research institute (207-396-8246) or the Maine Department of Agriculture, Conservation and Forestry (207-287-7615) if you find a mosquito trap that appears to be damaged or disrupted. The number should be listed on the trap.

Why are traps placed in certain locations?

  • During the busy season, traps are placed when there is evidence of a mosquito-borne illness, such as a sick horse or human, or in habitats where specific mosquitoes are found. [11, 12]

What happens when a mosquito pool tests positive?

  • Maine CDC notifies the submitter as well as the town if a mosquito pool tests positive.
  • The positive result for the town is posted on Maine CDC's Arboviral Surveillance webpage and published in Maine CDC's weekly arboviral report. [4]
gravid trap
Gravid Trap

Why does the state not release specific locations where positive mosquitoes are found?

  • The state releases the town with the positive result, but not the exact location of the trap. [4] The whole town is considered at risk if there is a positive mosquito pool anywhere in that town, since mosquitoes fly.


  1. Holman, M. S., Darsie, R. F., Jr., & Foss, K. A. (2006). A checklist of the mosquitoes of Maine with new state records. Journal of the American Mosquito Control Association, 22(2), 327-329.
  2. Lindsey, N. P., Staples, J.E., & Fischer, M. (2018). Eastern Equine Encephalitis virus in the United States, 2003-2016. The American Journal of Tropical Medicine and Hygiene, 98(5), 1472-1477.
  3. Lubelczyk, C., Mutebi, J-P., Robinson, S., Elias, S.P., Smith, L.B., Juris, S.A.,...Smith, R.P. Jr. (2013). An epizootic of Eastern Equine Encephalitis virus, Maine, USA in 2009: Outbreak Description and Entomological Studies. American Journal of Tropical Medicine and Hygiene, 88(1), 95-102. doi: 10.4269/ajtmh.2012.11-0358
  4. Maine Center for Disease Control and Prevention. (2018). Arboviral surveillance. Retrieved from
  5. Maine Department of Agriculture, Conservation and Forestry. (2013). Mosquito species occurring in Maine. Retrieved from
  6. Edillo, F., Kiszewski, A., Manjourides, J., Pagano, M., Hutchinson, M., Kyle, A.,...Culex pipiens Working, G. (2009). Effects of latitude and longitude on the population structure of Culex pipiens s.l., vectors of West Nile virus in North America. The American Journal of Tropical Medicine and Hygiene, 81(5), 842-848. doi: 10.4269/ajtmh.2009.08-0605
  7. Epstein, P.R. (2001). West Nile virus and the climate. Journal of Urban Health, 78(2), 367-371. doi: 10.1093/jurban/78.2.367
  8. Honnen, A-C., & Monaghan, M.T. (2017). City-dwellers and country folks: Lack of population differentiation along an urban-rural gradient in the mosquito Culex pipiens (Diptera: Culicidae). Journal of Insect Science, 17(5), 107. doi: 10.1093/jisesa/iex086
  9. Bosak, P.J., Reed, L.M., & Crans, W.J. (2001). Habitat preference of host-seeking Coquillettidia perturbans (Walker) in relation to birds and eastern equine encephalomyelitis virus in New Jersey. Journal of Vector Ecology, 26(1), 103-109.
  10. Brugman, V.A., England, M.E., Stoner, J., Tugwell, L., Harrup, L.E., Wilson., A.J.,...Carpenter, S. (2017). How often do mosquitoes bite humans in southern England? A standardized summer trial at four sites reveals spatial, temporal and site-related variation in biting rates. Parasites & Vectors, 10, 420. doi: 10.1186/s13071-017-2360-9
  11. Mutebi, J. P., Godsey, M., Smith, R. P., Jr., Renell, M. R., Smith, L., Robinson, S.,...Lubelczyk, C. (2015). Prevalence of eastern equine encephalitis virus antibodies among white-tailed deer populations in Maine. Vector Borne Zoonotic Diseases, 15(3), 210-214. doi: 10.1089/vbz.2014.1696
  12. Gibney, K. B., Robinson, S., Mutebi, J. P., Hoenig, D. E., Bernier, B. J., Webber, L.,...Fischer, M. (2011). Eastern equine encephalitis: An emerging arboviral disease threat, Maine, 2009. Vector Borne Zoonotic Diseases, 11(6), 637-639. doi: 10.1089/vbz.2010.0189