Mosquito Populations Underway

Tree holes (Figure 1) provide good winter refuges for the Asian tiger mosquito and other container-breeding species. In late summer, females glue their eggs inside the holes where they remain until spring.

During spring, enough water collected in the tree hole pictured in Figure 2 to cover mosquito eggs that were stuck to the wall the previous fall. Microorganisms growing in the water reduced its oxygen content, which, in turn, triggered egg hatch. Mosquito larvae are able to feed on the microorganisms swimming in the water.

Figure 1. Tree holes are good wintering sites for eggs of some mosquito species (Photo: Lee Townsend,UK).

Figure 1. Tree holes are good wintering sites for eggs of some mosquito species (Photo: Lee Townsend,UK).

Figure 2. Mosquito larvae were present on May 20, 2016

Figure 2. Mosquito larvae were present on May 20, 2016 (Photo: Lee Townsend, UK)

Figure 3. Water collected from the tree hole in Figure 1 contained over 2 dozen mosquito larvae (Photo: Lee Townsend, UK).

Figure 3. Water collected from the tree hole in Figure 1 contained over 2 dozen mosquito larvae (Photo: Lee Townsend, UK).

Larvae of the Asian tiger mosquito can develop anytime water temperature is above 50.7oF. The rate of development increases with temperature. A life cycle takes about 35 days at 60oF but only about 9 days at 86oF.

Females developing from overwintering populations will ultimately search for egg-laying sites of their own. Asian tiger mosquitoes prefer to lay their eggs at ground level, if possible. As the mosquito population grows, so does the competition for breeding sites. Artificial containers (such as Figure 4) meet this need.

Figure 4. A discarded split plastic water bottle containing some dirty water is a potential mosquito breeding site (Photo: Lee Townsend, UK).

Figure 4. A discarded split plastic water bottle containing some dirty water is a potential mosquito breeding site (Photo: Lee Townsend, UK).

Sanitation can eliminate mosquito breeding sites. Thorough weekly checks of potential sites are important in reducing mosquito numbers.

 

By Lee Townsend, Extension Entomologist

 

Posted in Household Pests