Temperature Fluctuations Affect Population Growth Rate of Dengue Mosquito
The PLOS ONE journal published “Effects of Fluctuating Daily Temperatures at Critical Thermal Extremes on Aedes aegypti Life-History Traits," written by lead author Lauren Carrington and four other scientists from Thomas Scott’s Mosquito Research Laboratory and the Center for Vectorborne Diseases (CVEC).
Their work analyzed how natural temperature fluctuations affect the population growth rate of the dengue mosquito. Basically, temperature effects on larval development time, larval survival and adult reproduction depend on the combination of mean temperature and the magnitude of fluctuations.
“The effect of temperature on insect biology is well understood under constant temperature conditions, but less so under more natural, fluctuation conditions,” said Carrington, who completed her three-year postdoctoral fellowship last December in the Scott lab and continues research projects with the lab. She is now based at the Nossal Institute for Global Health, University of Melbourne, Australia.
The research is expected to lead to greater accuracy of applications for mosquito surveillance and disease prevention.
“An improved understanding of mosquito responses to natural temperature variation,” Carrington said, “will enhance the effectiveness of vector control strategies, thereby reducing transmission of mosquito-borne diseases, such as dengue fever.” By using constant temperatures, scientists can under- or -over estimate values, she said.
“In the field, mosquitoes, and other insects, are exposed to a constantly changing environment, with fluctuations in temperature throughout the day, every day. In the lab, however, experimental protocols generally try to minimize as much variability as possible, and temperature is often the first element to be standardized.”
Co-authors are Veronica Armijos, Christopher Barker, Louis Lambrechts and Thomas Scott.
Dengue is spread by an infected female Aedes aegypti mosquito, a day-biting, limited flight-range mosquito that prefers human blood to develop its eggs. Dengue is caused by four distinct, but closely related, viruses and the most severe form of disease is life-threatening dengue hemorrhagic fever or DHF.
Some 500,000 people with severe dengue are hospitalized each year, according to the World Health Organization (WHO), and about 2.5 percent of those affected die.
“Dengue takes an enormous toll on human health worldwide, with as many as 4 billion people at risk—half of the world’s population--and 400 million new infections each year,” said Scott, a professor of entomology at UC Davis and active in CVEC.
Dengue mosquito, Aedes aegypti. (Photo courtesy of Centers for Disease Control and Prevention)