## 3 Results  
### Laboratory Experiments  
In the laboratory, the effect of the ultrasonic wave spectrum at a frequency of 18 to 30 kHz caused 100% mortality on _Ae. aegypti_ larvae and pupae at 20 cm distance from the transducer after an exposure of 30 s, and 100% mortality of instars I, II, and III at 35 cm after an exposure of 30 s. It takes 180s to kill all pupae at a distance of 60 cm (Figure 2). The mortality rates of _Ae. aegypti_ were direct positively proportional to the exposure time (\(p<0.05\)). All instars and pupae had 100% mortality at 20 cm after an exposure of 60 s (\(p<0.05\)). With increasing exposure time and fixed distance to the transducer, the percentage of _Ae. aegypti_ larval mortality also increased (\(p<0.05\)) (Figure 2). Two-way ANOVA results showed that the distance, exposure time, and their interaction significantly impacted each young instar stage of _Ae. aegypti_ (\(p<0.001\), Table 1). Among younger instars of this species, the fitted regression model revealed that mortality (%) was significantly correlated to distance and exposure time (\(p<0.001\), Table 2). The coefficient values of distance were negative and showed a decreasing trend with extended space, whereas positive coefficient values of time indicated that accumulated effects increased the control efficiencies. In our research, we used different life stages (I-IV larval instars and pupae) of the mosquito _Ae. aegypti_, as well as adults of the copep _M. formosanus_ (Figure 3). No mortality was found on the non-target copep _M. formosanus_, as well as in pretreatments of mosquito larvae. The mortality of _Ae. aegypti_ larvae caused by the Larvasonic device probably resulted from the sound energy transmitted into the water at a high frequency, leading to ruptures of the dorsal tracheal trunk in young mosquito instars, thus resulting in major tissue damage and death (Figure 4). Figure 1: Map showing the field sample collection and study areas in Taiwan. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Source** & \multicolumn{2}{c}{**Type III Sum of Squares**} & _df.f._ & **Mean Square** & **F** & _p-value_ \\ \hline \multicolumn{5}{c}{I instar larva} \\ Distance (cm) & 0.99 & 12 & 0.08 & 18.24 & \textless{}0.001 \\ Time (s) & 0.35 & 5 & 0.07 & 15.36 & \textless{}0.001 \\ Distance (cm) \(\times\) Time (s) & 1.23 & 60 & 0.02 & 4.54 & \textless{}0.001 \\ Error & 1.41 & 312 & \textless{}0.01 & & \\ \multicolumn{5}{c}{II instar larva} \\ Distance (cm) & 1.66 & 12 & 0.14 & 47.86 & \textless{}0.001 \\ Time (s) & 0.76 & 5 & 0.15 & 52.79 & \textless{}0.001 \\ Distance (cm) \(\times\) Time (s) & 2.27 & 60 & 0.04 & 13.09 & \textless{}0.001 \\ Error & 0.90 & 312 & \textless{}0.01 & & \\ \multicolumn{5}{c}{III instar larva} \\ Distance (cm) & 2.29 & 12 & 0.19 & 37.74 & \textless{}0.001 \\ Time (s) & 0.98 & 5 & 0.20 & 38.81 & \textless{}0.001 \\ Distance (cm) \(\times\) Time (s) & 2.16 & 60 & 0.04 & 7.15 & \textless{}0.001 \\ Error & 1.57 & 312 & 0.01 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Results of two-way ANOVA testing the effect of distance and exposure time on _Aedes aegypti_ young instars. The values of _df.f._ = degree of freedom, significance level \(p\) \(<\) 0.05. Figure 2: Mosquito mortality (%) achieved by the Larvasonic treatment over different conditions on _Aedes aegypti_ young instars. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Source** & **Type III Sum of Squares** & _d.f._ & **Mean Square** & \(F\) & _p-value_ \\ \hline \multicolumn{5}{c}{IV instar larva} \\ Distance (cm) & 5.69 & 12 & 0.47 & 68.03 & \(<\)0.001 \\ Time (s) & 1.94 & 5 & 0.39 & 55.75 & \(<\)0.001 \\ Distance (cm) \(\times\) Time (s) & 3.67 & 60 & 0.06 & 8.78 & \(<\)0.001 \\ Error & 2.17 & 312 & 0.01 & & \\ \multicolumn{5}{c}{Pupa} \\ Distance (cm) & 9.06 & 12 & 0.76 & 24.30 & \(<\)0.001 \\ Time (s) & 3.21 & 5 & 0.64 & 20.64 & \(<\)0.001 \\ Distance (cm) \(\times\) Time (s) & 6.11 & 60 & 0.10 & 3.27 & \(<\)0.001 \\ Error & 9.70 & 312 & 0.03 & & \\ \hline \hline \end{tabular}
\end{table}