Publications and Presentations

Safe and effective mosquito repellents applicable to human skin are an important means to prevent the spread of mosquito-borne infectious diseases. In recent years, it has been confirmed that hydrophobic liquids such as low-viscosity polydimethylsiloxane (L-PDMS) can spread on the surface of human skin and prevent mosquito landing. This effect is attributed to the ability of L-PDMS to wet mosquito legs.
In this study, we newly identified three effects of L-PDMS on Aedes albopictus (the Asian tiger mosquito). First, when L-PDMS was mixed with conventional repellent ingredients such as citronella oil or DEET and applied to the skin, the silicone oil, owing to its ability to easily spread over mosquito legs, facilitated the transfer of these repellent ingredients to the legs and significantly enhanced their repellent effects. Second, when L-PDMS adhered to mosquito legs, it reduced their ability to track objects during flight. Third, when mosquitoes with L-PDMS and citronella oil applied to their legs were tested, their repellent behavior toward citronella oil was further enhanced.
These findings demonstrate that L-PDMS can alter mosquito behavior in multiple ways.

Mosquitoes transmit diseases such as malaria and dengue fever, claiming hundreds of thousands of lives worldwide each year. Therefore, controlling mosquitoes is critically important; however, conventional insecticides present issues such as ecological impact and the development of insecticide resistance in mosquitoes. In this study, we explored the possibility of controlling mosquitoes without relying on insecticidal components, by using surfactants such as those found in detergents. Experiments were conducted on Aedes albopictus (the Asian tiger mosquito), focusing on solutions with low surface tension—particularly aqueous surfactant solutions—and analyzing how these liquids affect mosquito behavior by wetting their hydrophobic body surfaces. As a result, we found that when solutions with low surface tension attached to the body and wings of mosquitoes, the insects fell. Furthermore, as surface tension decreased, the mosquito body surface became wetted more quickly and extensively, leading not only to mosquitoes falling but also to their knockdown. These findings suggest that surfactants may provide a way to control mosquitoes without the need for conventional insecticidal components.