When two mosquitoes meet to mate, each modulates its flight tones such that the female’s 3rd and the male’s 2nd harmonic frequencies are equivalent. We show that this phenomenon is an example of synchronization, which is common in nature. The mosquito’s flight tone acts as an external signal, stimulating its partner to adjust the wing beat rhythm to achieve the synchronization state. A simplified model, which is based on the frequency ratio difference feedback mechanism, is proposed to describe the harmonic convergence of mosquitoes. Furthermore, we proposed a method to characterize the energy dissipation in the frequency alteration, and the results demonstrate that 3/2 frequency locking is an optimal selection to mosquitoes. When compared with other possible ratios, the mosquitoes expend minimum energy if they lock the synchronizing state at a ratio of 3/2. When two mosquitoes meet to mate, each modulates its flight tones such that the female’s 3rd and the male’s 2nd harmonic frequencies are equivalent. We show that this phenomenon is an example of synchronization, which is common in nature. The mosquito’s flight tone acts as an external signal, stimulating its partner to adjust the wing beat rhythm to achieve the synchronization state. A simplified model, which is based on the frequency ratio difference feedback mechanism, is proposed to describe the harmonic convergence of mosquitoes. characterize the energy dissipation in the frequency alteration, and the results demonstrate that 3/2 frequency locking is an optimal selection to mosquitoes. When compared with other possible ratios, the mosquitoes expend minimum energy if they lock the synchronizing state at a ratio of 3 / 2.