Laboratory studies of oviposition site choice of Toxorhynchites splendens: Role of larval holding-rearing water and predator-prey interactions

Oviposition preference by Toxorhynchites mosquito species is an important aspect of their biological control potential. When ovipositing, the females deposit individual eggs by hovering above the water, indicating that they may be capable of detecting chemical cues from above the water surface. These chemical cues may help the females to determine whether the water is suitable for their larvae. We investigated whether female Tx. splendens has the ability to discriminate against oviposition sites in habitats containing turbid larval/pupal rearing water and predator-prey treatments. In this study, the number of eggs in the test and control cups were compared to assess oviposition preference. According to the results, female Tx. splendens preferred ovipositing in cups with turbid immature water (prey absence) and predator-prey turbid water (prey and predator presences) over ovi-positing in filtered water as a control. Results from the third experiment revealed that cups with alive and dead Ae. aegypti larvae proved strongly attractive to Tx. splendens females, while those from conspecific Toxorhynchites larvae caused oviposition deterrence when compared to other treatments in a dual choice test. Our results indicated that both turbid immature water and predator-prey turbid water can efficiently attract Tx. splendens females to deposit eggs. These findings will aid in the development of Toxorhynchites mosquito as a biocontrol agent for the control of Aedes spp. larvae.

Automated summary

Female Tx. splendens mosquitoes show a clear preference for oviposition sites with turbid water and the presence of live or dead predators. These findings are crucial for the development of Toxorhynchites mosquitoes as biocontrol agents against Aedes larvae.