Asian tiger mosquitoes, Aedes albopictus, are vectors for yellow fever, dengue, chikungunya, and other infectious diseases, and they’ve been making their way through front lawns and backyards across the U.S. According to a new Journal of Medical Entomology study, they prefer to lay their eggs in water near flowering plants. The findings could help us better control these pesky bloodsuckers.
Mosquitoes are known to utilize flowering plants for the sugar, but little is known about how this might influence their choice of sites for oviposition (or egg-laying). Residential areas landscaped with lots of different flowering plants provide plenty of potential larval developmental sites for container-breeding mosquitoes like Aedes albopictus. The females typically acquire and transmit the disease-causing microbes while taking bloodmeals.
To better understand their egg-laying preferences, University of Florida’s Timothy Davis and colleagues studied gravid (or pregnant) female Aedes albopictus in a closed greenhouse, then in three large outdoor enclosures with screens, and finally in four suburban backyards in and around Gainesville, Florida.
The mosquitoes had access to flowering butterfly bush (Buddleja davidii) plants and containers of up to three sizes (473, 946, and 1,892 milliliters) filled with an oak leaf infusion. In the large enclosures, the containers were sometimes next to a bush with its flowers removed; in the enclosures and the backyards, other species of flowering plants were also present. Seed germination paper was used to line the containers, and the eggs were counted 48 hours after the mosquitoes were released.
The team found significantly more eggs in the largest containers with higher volumes of water and significantly more eggs in containers next to flowering bushes (compared to containers without flowers). Flowering butterfly bushes seem to exert a greater influence over oviposition decisions than container size: In the large enclosure study, 69.28 percent of Aedes albopictus eggs were deposited in containers near the flowers.
Nectar is an important energy source, and gravid females are attracted to flowering plants to not only feed themselves but probably also to provision for their offspring. "Exploiting the attractiveness of flowering butterfly bushes in developing control techniques could assist in stopping pathogen transmission," Davis said in a statement. If researchers can isolate and replicate whatever’s attracting the mosquitoes, they might be able to lure egg-laying females into traps.
