Optimizing ovitrap design: the role of ovistrip texture, colour, and water in modulating oviposition behavior of Aedes vector mosquitoes

Ovitrap surveillance of Aedes vectors in Sri Lanka needs improvement to effectively monitor vector abundance in dengue high-risk areas and detect emerging infestation zones. A study was conducted in two dengue high-risk areas, Narahenpita and Battaramulla in the Western Province, to assess the influence of ovistrip texture, color, and water type on Aedes oviposition, while adhering to WHO guidelines. The relationship of OI and the mean number of eggs per trap with ovitrap designs were determined by General Linear Model (GLM), which revealed a significant difference in the OI between the two study sites (P=0.005), while the mean number of eggs per ovitrap did not differ significantly (P=0.134). Water type had no significant influence on OI and mean number of eggs per ovitraps. A significant effect of ovistrip type (F=6.73, P<0.001) was found on OI and mean egg per trap (F=9.85, P<0.001), where filter paper exhibited the largest coefficient in magnitude (-0.1698), indicating a strong negative correlation with OI and mean eggs per trap (-2.445) while white fabric showed a strong positive co-efficient magnitude with OI (0.1108) and mean egg per trap (1.605). According to Spearman's rank correlation, the rainfall did not have a statistically significant effect on the number of eggs collected or the OI. The study suggested that fabric ovistrips colored white combined with rainwater or tap water, make ovitraps highly effective for Aedes vector surveillance, while the currently used filter paper ovistrip having a negative effect on the egg number laid.