Impact of olfactory sensitivity preferences on midgut pathophysiology of Aedes mosquitoes towards different sugar variants

The effective control of Aedes mosquitoes is increasingly challenging due to the presence of insecticide resistance in mosquitoes. Hence, attractive toxic sugar baits (ATSBs) can be used as an alternative strategy to insecticides. The introduction of suitable attractants into baits is crucial, as it determines the number of mosquitoes attracted to them. This study involved the preparation of ATSBs as a medium for liquid bait carriers aimed at developing mosquito baiting tools. Aedes aegypti and Aedes albopictus were tested for non-choice and choice assays against various ATSBs (mango, Chrysanthemum, and their mix). In addition, olfactory preference index for mosquitoes was calculated using preference index formula followed by independent t- test to determine the significant differences, (p < 0.05) between ATSBs various choices. Furthermore, the midgut tissue of the mosquitoes was observed by using histology method. The wild and lab strain Ae. aegypti showed a significant attractancy towards mango ATSBs with a value of (p = 0.004) and (p = 0.04) respectively. Mango attractant is the most preferred by both Aedes sp. However, the mix ATSBs is secondarily preferred while Chrysanthemum is the least preferred ATSBs. The histology results showed that the midgut of mosquitoes that feed on the treated ATSBs exhibit alteration and degeneration. In the context of integrated pest management, the application of ATSBs in mosquito control may diminish the reliance on chemical pesticides, as natural substances include inherent volatile emissions that attract or repel insects. Consequently, the continuous release of the natural attractant odour may play a significant role in the attractive toxic sugar bait, acting as both an attractant and a lethal mechanism to combat disease transmitted by mosquitoes in the future.