How does the toxin from bacillus thuringiensis israelensis (Bti) affect mosquito larvae?

The toxin from Bacillus thuringiensis israelensis (Bti) specifically targets the gut of mosquito larvae. When these larvae ingest the Bti spores, the toxins produced by the bacteria are activated in the alkaline environment of their intestines. This process leads to the formation of crystals that create pores in the gut lining, resulting in disruption and eventual death of the larvae. This mode of action specifically illustrates Bti's efficacy as a biological control agent, as it harms the larvae where they process their food, effectively stopping their ability to feed and develop further.

Bti is renowned for its selectivity, which means it primarily affects mosquitoes and certain other dipteran species, minimizing harm to most beneficial insects and the environment. Understanding this mechanism is crucial for using Bti effectively in mosquito control programs, as it allows for targeted reductions in mosquito populations while preserving other beneficial species in the ecosystem.