Effects of marking methods and fluorescent dusts on Aedes aegypti survival.

BACKGROUND

Tracking the movement of mosquitoes and understanding dispersal dynamics is essential for the control and prevention of vector-borne diseases. A variety of marking techniques have been used, including dusts and dyes.

METHODS

In this study, Aedes aegypti were marked using fluorescent dusts ('DayGlo': A-19 Horizon Blue & A-13-N Rocket Red; 'Brian Clegg': pink, blue & red), fluorescent paints ('Brian Clegg': blue, red & yellow) and metallic gold dust ('Brian Clegg'). Dusting methods were those previously used in mark-release-recapture experiments, including application with a bulb duster, creation of a dust storm or shaking in a bag.

RESULTS

Results showed marking mosquitoes using a dust storm allowed relatively high survival, compared to unmarked controls (Males: χ² = 3.24, df = 4, p = 0.07; Females: χ² = 3.24, df = 4, p = 0.04), and high marking efficiency. Using a bulb duster showed high survival in male mosquitoes (χ² = 12.59, df = 4, p < 0.000), but low survival in female mosquitoes during the first 15 days of the study (χ² = 5.17, df = 4, p < 0.05). The bulb duster also had the lowest marking efficiency compared to other dry marking techniques. The bag method showed low survival in males during the first 15 days of the study (χ² = 5.77, df = 4, p < 0.05). Applying paints had an overall negative impact on survival for males (χ² = 5.03, df = 3, p < 0.05), but not for females (χ² = 0.19, df = 3, p = 0.661). Males dusted with DayGlo Horizon Blue dust, and females dusted with DayGlo Rocket Red dust, had the most significant reduction in survivorship in comparison to the control (Males: χ² = 15.70, df = 6, p < 0.000; Females: χ² = 24.47, df = 6, p < 0.000). Mosquitoes marked with Brian Clegg gold dust showed mortality rates similar to controls within male mosquitoes (χ² = 0.18, df = 6, p = 0.674), but significantly lower in females (χ² = 16.59, df = 6, p < 0.000).

CONCLUSIONS

This study showed that marking technique and colour can have a significant impact on the survival and marking coverage of a mosquito.