Mortality Rates in Musca domestica (Diptera: Muscidae) Adults after Exposure to Sound Frequencies Lower and Higher than the Ultrasonic Limits

This study investigated the effects of acoustic sound frequencies including sub-ultrasonic and ultrasonic levels on the mortality of adult house flies (Musca domestica). A total of 240 flies were exposed to four frequencies: 6.00 kHz and 14.30 kHz (sub-ultrasonic), 20.00 kHz (ultrasonic threshold), and 25.50 kHz (ultrasonic), with three replicates per frequency. Mortality was recorded at six time points (1st, 2nd, 4th, 6th, 8th, and 24th hours). Statistical analyses (one-way ANOVA and Pearson correlation) were used to evaluate the influence of frequency and exposure duration on mortality. The highest mortality rate (76.66%) occurred at 25.50 kHz after 24 hours, whereas the lowest (26.66%) was recorded at 14.30 kHz. Mortality increased markedly over time, from 3.00% and 6.19% during the first two hours to 74.26% in 24 hours. Pearson correlation indicated significant positive associations between both frequency and mortality (r = 0.455, P<0.01) and exposure duration and mortality (r = 0.525, P<0.01). One-way ANOVA confirmed a significant frequency effect (F = 7.210, P<0.001). However, Levene’s test (P<0.05) showed variance heterogeneity, warranting cautious interpretation. Overall, higher frequencies and longer exposures increased mortality in a dose- and time-dependent manner, with ultrasonic levels showing the strongest effect.