UNIVERSITY PARK, Pa. -- Temperature-driven changes alter outbreak patterns of tea tortrix -- an insect pest -- and may shed light on how temperature influences whether insects emerge as cohesive cohorts or continuously, according to an international team of researchers. These findings have implications for both pest control and how climate change may alter infestations.
"While the influence of temperature on individual-level life-history traits is well understood, the impact on population-level dynamics, such as population cycles or outbreak frequency is less clear," the researchers report in today's (Aug. 1) issue of Science Express.
Researchers currently use temperature to predict the number of generations that appear each year and the timing of the various insect life stages, which is critical for scheduling pest control.
"While we had a really good record of temperature and the number of cohorts that appeared each season, we had no clear understanding of the difference between distinct and continuous reproduction," said Ottar N. Bjørnstad, professor of entomology, biology and statistics, Penn State. "Understanding the timing of generations is important because typically insecticides work only during one or two of the life stages of these pests."
The researchers looked at more than 50 years of data on the tea tortrix and also developed an independent mathematical population model that can predict population dynamics under both constant and seasonally driven temperature regimes.
While the tea tortrix is native to Japan, many similar moths exist in North American including the spruce bud moth, grape berry moth, light brown apple moth and summer fruit tortrix.