Employing tiny harmonic radar tags to study mosquito movement in natural environments

A detailed understanding of mosquito movement dynamics is critical to mosquito-borne disease prevention. While laboratory- and trap-based studies have made great strides in providing snapshots of mosquito movement, a real-time comprehensive picture of quotidian mosquito movement is still lacking. However, the development of miniature harmonic radar (HR) tags, suitable for small insect tracking, has made the collection of fine-scale mosquito movement data (locating landing positions) possible. In this study, we assessed the suitability of using HR tags (weighing 50-135 μg) for tracking individual Aedes albopictus in both caged flight tests and natural environments. Flight tests in a large outdoor screen cage demonstrated that mosquitoes were attracted to a darker-colored wall and that individuals had variable landing heights, which aligned with published descriptions of A. albopictus behavior. Field experiments demonstrated the feasibility of following tagged mosquito movements in a coffee field and in shaded parkland. Movement parameters from both field experiments (step distances, turning angles, and movement rates) were used to estimate maximum daily dispersals (range 25-52 m/day), and these estimates agree with previously published estimates. While both non-blood-fed and blood-fed female A. albopictus were found to be flight capable with HR tags, several experiments showed some adverse effects of tagging, including increased mortality and decreased flight times. Nonetheless, our findings suggest that using HR tags to track mosquitoes can yield biologically relevant results. This approach is promising for future studies investigating adult mosquito movement ecology and dispersal, thus revealing further possibilities for mosquito surveillance and control.