Range expansion of the Asian tiger mosquito in NYS
Climate Change, Adaptation, and Range Expansion of the Asian Tiger Mosquito in New York State
The Asian tiger mosquito - a very competent disease vector - was first introduced into the US in the 1980s. This project has led to better monitoring approaches and a greater understanding of how far and how fast this pest can spread, aided by a changing climate.
How big a threat is Asian tiger mosquito (Aedes albopictus) to us in New York? Since its US introduction in the 1980s, this mosquito is expanding its range, primarily driven by changes in climate. It is one of the best all-around mosquito vectors of human and animal diseases, and can transmit over 20 known diseases (including dengue, chikungunya, zika, and West Nile viruses). To help assess risk from this invasive mosquito, we: (1) investigated biological traits and conditions that allow it to spread, (2) mapped its range expansion in New York, and (3) investigated strategies for rapid, large scale egg surveillance.
We conducted larval surveys over two years across nine sites in residential neighborhoods in southern New York. These neighborhoods included a range of socio-economic status and percent impervious surface (Fig. 1). In addition, we characterized the weather conditions that trigger dormancy in Ae. albopictus along the edge of its invasive US range. For this work, we tested the hypothesis that the timing of Ae. albopictus dormancy with respect to weather conditions is both rapidly changing and variable, especially along its northern range of invasion. Egg traps were set out from August to November of each year.
There was a near doubling of the overall mosquito abundance over the three-year duration of the study. But we also found dramatic variability in abundance from year to year. Ae. albopictus were more likely to be found in shaded containers with dead organic material, but were not more likely to be found in any one container type. Their distribution was more clustered in sites where the median household income was greater. Thus biting risk is not uniformly distributed, but varies based on income level and urban development, indicating that different control strategies would be most efficient depending on the nature of the location. In studying dormancy, we found that egg count was highest from our first (August) collection and dropped gradually as the weeks progressed. Our results indicate that: 1) temperature may play a large role in triggering dormancy and that response to the environment varies greatly, 2) the population-wide switch to dormancy can be gradual and non-linear, and 3) dormancy behavior can vary between relatively nearby populations. These results may help us both understand the mechanisms underlying dormancy in these mosquitoes and reshape models of current and future population growth and spread in NY. We also developed an egg identification guide for Aedes container mosquitoes in NY. The guide includes a description of methods for preparing eggs and observing them under a compound microscope, as well as key features for clearly differentiating Ae. albopictus eggs from other mosquito species (Fig 2). These features geometric patterning, ridge shape, and reflectance of the outer shell of the eggs. The guide will be freely available on our website and will save significant time for field workers monitoring the Asian tiger mosquito using egg traps.
Website: New York State Tiger Mosquito Education Network (TigerNET)
- Funding Source: Hatch
- Statement Year: 2018
- Status: Completed project
- Topics: Mosquitos, invasive species, human health