Aedes triseriatus
tree hole mosquito

Aedes triseriatus, commonly called the tree hole mosquito, or eastern tree hole mosquito, is a species of mosquito found in the western hemisphere in wooded regions of eastern and central North America. It is quite prevalent, ranging from New Brunswick to the Florida Keys and stretching as far west as central Texas. (Horsfall 1955, Crans 2001)

Aedes triseriatus makes its home in areas where it can locate temporary pools of stagnant water, such as tree holes, abandoned tires, or leaf clogged gutters. It favors pools which contain leaf debris and other organic material to provide food for its larvae. Adults remain in areas near larval habitats throughout their lifespan. Multiple generations may coexist during periods of frequent flooding in the summer, and the last eggs layed during the summer lie dormant through the winter. This adaptation permits Aedes triseriatus to survive in environments which are too harsh for the fragile bodied adult mosquito. (Horsfall 1955, Carpenter and Durland 1982, Crans 2001).

Aedes triseriatus begins its life cycle as an egg laid close to a shallow pool of water by the female. Once the pool is flooded and conditions are right, the eggs hatch and free-swimming larvae emerge. The larvae feed in the pool, straining organic material and microorganisms from the water. Aedes triseriatus can be identified among other mosquito species at this stage because its body is longer than most other mosquito larvae. The larvae are gray colored and swim with a snake- like wriggle. The next stage in the mosquito's life cycle, the pupae, is also aquatic, with a thicker, darker, rounded body and a tail that propels them through the water. Following this stage, the adult emerges as a dark black mosquito with silvery white scales along the sides of its thorax. (These silvery-white scales are diagnostic.) The tarsi and proboscis are completely dark. The adult mosquito is a winged insect, with one pair of wings, three pairs of legs and the three distinct regions typical of an insect's body (the head, thorax and abdomen), as well as an extended mouth region called the proboscis for sipping nectar, and, in the females, sucking blood. (Walker 1992, Crans 2001, "The Biology of the Mosquito" 2001, "Mosquito Pest Management" 2001)

The most widely recognized behavior of this and many other mosquitoes is the females' practice of biting and drawing blood from humans, other mammals, and birds. While many species of mosquitoes are most active around sunset, Aedes triseriatus will bite during the day, especially in shady areas or in indoor artificial light.

One of the most important behaviors of this species relevant to its survival from one generation to the next is a phenomenon referred to as larval diapause. This is a period of dormancy as an egg, which can last for more than a year and enables the mosquito to survive freezing temperatures in areas of Canada and the U.S. with very cold winters. The diapause is controlled by several factors, including daylight and temperature, the direct relationships of which are still being studied, and that are known to vary between different regions (Horsfall 1955, "Vector Physiology" 2001, "Biology of the Mosquito" 2001).

Females lay their eggs in containers of stagnant water to ensure a rich supply of nutrients and bacteria on which their larvae may feed. The larvae gain the energy they need for development by filtering through the organic material. While both male and female adult Aedes triseriatus feed mainly on nectar, deriving their energy from sugars, the female requires a blood meal to obtain proteins critical for the production of eggs, and thus functions as a parasite on birds and mammals. (Carpenter and Durland 1982, "Biology of the Mosquito" 2001)

This species of mosquito is a special problem as an ectoparasite because it feeds on both birds and mammals, and thus can harbor and transfer a variety of viruses, posing a threat to humans and other mammals. Aedes triseriatus has been identified as a vector of Eastern Equine Encephalitis and linked to the spread of LaCrosse Encephalitis.

(Bates 1949, "Mosquito Pest Management Bulletin" 2001)

Aedes triseriatus may certainly play a role in the food chain and ecosystem of its woodland habitats, but as an ectoparasite it is not considered to be of direct benefit to humans.

Aedes triseriatus like many mosquito species, is a very hardy organism, and most ecological focus is aimed at controlling it rather than concern for its ability to propagate. ("Mosquito Pest Management" 2001).