## 4 Discussion  
Ultrasound-based devices have been tested in a number of pest control attempts, developing several tools that provide sounds aiming to repel, deter, or kill unwanted animals such as arthropods, birds, rodents, and even larger mammals [41]. In particular, acoustic devices of various sizes and power levels were used successfully for insect pest management [42]. In our experiments, the morphological analysis of treated and killed _Ae. aegypti_ larvae confirmed our hypothesis that the acoustic energy from the transducer broke the mosquito tracheal trunk in this species (Figure 4). It should also be noted that no matter the source and visibility by their avoidance, mosquitoes are able to detect ultrasound at a  
Figure 6: **(a)**_Aedes aegypti_ larval mortality after of Larvasonic treatment. Asterisks indicate significant differences between control and treatment mortalities (ANOVA, Tukey’s honestly significant difference (HSD) test, \(p<0.05\)). **(b)** Total mosquito larval mortality and survival after Larvasonic treatments. Data and statistical analysis consider the proportion of larvae/pupae killed or surviving and not absolute numbers that were killed. wavelength range of 38-44 kHz [43]. In agreement with our findings, [PERSON] et al. [44] recently reported the efficacy of a Larvasonic Field Arm Mobile Wetlands Unit and SD-Mini in controlling _Culex_ spp. mosquito populations, without any harmful effect on non-target organisms, including damselfflies and dragonflies. Furthermore, [PERSON] et al. [45] highlighted that ultrasonic waves at a frequency of 0.5 mc/s effectively inhibited the egg hatchability in _Ae. aegypti_. Also, [PERSON] et al. [46] noticed that the Larvasonic SD-Mini acoustic larvicide achieved 90% mortality against _Ae. aegypti_. Besides, [PERSON] and [PERSON] [47] reported that five ultrasonic waves at frequencies of 20-70 kHz were effective in repelling mosquitoes. From a mechanistic point of view at the cellular level, ultrasounds can cause membrane blubbing, shrinkage of cells, fragmentation of nuclei, chromatin condensation, and the fragmentation of apoptotic bodies [48; 49; 50]. [PERSON] et al. [51] observed cuticle holes that were likely caused by ultrasound cavitation. Such portions can damage or kill mosquito larvae if the tissue holes are too large or if the tissues cannot reseal fast enough. In our research, we noticed that the tested sound waves resonate at the frequency of mosquito larva internal air volume, causing the larvae to burst. As a result, 98% of larvae and pupae were dead and the remaining 2% were alive with morphological deformation, ultimately resulting in their mortality within a short span of time. Concerning the impact of ultrasound on non-target organisms, we observed that ultrasonic waves employed at a frequency of 18 to 30 kHz did not exhibit noticeable harmful effects on the copep _M. formosanus_, which is a useful natural predator of mosquito young instars [52; 53; 54]. Vibrations caused by sound waves lead to the formation of gas vesicles that then resonate within and among the cells. Bubbles develop within cells, expand, and contract in a process of cavitational extension. Ultrasonic treatment leads to ruptures of the bubbles that are damaging the cells. Cavitational extension and with it the damaging effect on cells, is regulated by the frequency, intensity, and duration of sound waves [27]. These effects of ultrasonic waves do not only hold for mosquito young instar management but also for algal control. Other effects of ultrasonic waves include additional damage of cell membranes due to lipid peroxidation, and effects on the cell division cycle as evidenced from cyanobacteria [55; 56]. [PERSON] et al. [57] investigated the dynamics of microcystin release and degradation when _Microstis_ suspensions were treated with different ultrasound intensities and frequencies. [PERSON] and [PERSON] [58] showed that ultrasound can induce cavitation and mortality in veliger, juvenile, and adults of the invasive zebra mussel, applying 20-380 kHz.