A research group led by Shine Shane Naing (Myanmar), a second-year doctoral student (government-sponsored student) at the Graduate School of Environmental, Life and Natural Sciences, Okayama University, and Professor Takahisa Miyatake, discovered through experiments using blowflies that excessive intake of caffeine has an insecticidal effect.
Caffeine, which is found in coffee and tea, is known to activate dopamine and elevate the mood of humans. It is also known to activate insects, such as flies and improve the learning and memory abilities of honeybees, and has long been used in experiments to kill insects and control pests. However, the results have been mixed.
The research group fed adult blowflies various concentrations of sugar water to examine the effects on lifespan, activity, and lipid changes, and found that flies lived longer with 4% sugar water. Next, they mixed 4% sugar water with different concentrations of caffeine, and all of the flies that drank sugar water containing 0.5% or more of caffeine died within a week.
The researchers found that caffeine at lower concentrations did not have any insecticidal effect. They also found that caffeine reduced the amount of walking activity and the amount of fat in the body of adult flies. However, the relationship between the reduced walking activity and fat mass and the shorter life span of flies has not been clarified.
The research group believes that because excessive consumption of caffeine showed a clear insecticidal effect, it could potentially be used as an insecticide.
