Comparison of the tracheal systems of Anopheles sinensis and Aedes togoi larvae using synchrotron X-ray microscopic computed tomography (respiratory system of mosquito larvae using SR-μCT)

Mosquito-borne diseases, such as malaria, dengue fever, and Zika virus, are serious global health issues. Vector control may be an important strategy in reducing the mortality caused by these diseases. The respiratory system of mosquito larvae in the water has to inhale atmospheric oxygen as aquatic organisms. In this study, the three-dimensional (3D) structures of the dorsal longitudinal trunks (DLTs) of the tracheal systems of Anopheles sinensis and Aedes togoi were compared using synchrotron X-ray microscopic computed tomography. DLT respiratory frequencies were also investigated. Interestingly, the larvae of the two mosquito species exhibit tracheal systems that are both morphologically and functionally distinct. A. sinensis hangs horizontally under the water surface, and has a smaller DLT volume than A. togoi. In contrast, A. togoi hangs upside down using a siphon by fixing its tip to the water surface. The frequency of peristaltic movement in A. togoi is higher than that of A. sinensis. These differences in the structures and breathing behaviors of the respiratory systems of mosquito larvae provide new insights into the tracheal systems of mosquito larvae, which should help develop novel effective control strategies targeting mosquito larvae.