Does biological mosquito control (Bacillus thuringiensis var. israelensi:s: Bti) affect terrestrial food web structure?

The microbial agent Bacillus thuringiensis var. israelensis (Bti) is used worldwide to control mosquitoes and other biting dipterans. However, its effects on non-target biodiversity are unclear and widely debated. For example, how does it affect terrestrial food webs and its interactions?

Here we will use a food web based approach to evaluate how species not directly affected by Bti are affected indirectly by changes of abundance in target species affected by Bti application.

The main aim of this proposal is to understand the impact of Bti on food web interaction between insects and their predators.

More specifically we will: 1) Estimate abundance of emerging aquatic insects in areas with and without Bti application, 2) Estimate abundance of terrestrial insects and top predators in areas with and without Bti application, 3) Determine diet of insect and spider predators (mesopredators) and bird and bat predators (top predators) in areas with and without Bti application, 4) Describe differences in food web interactions and food web structure between the areas with and without Bti applications.

We will use these state-of-the-art methods (DNA metabarcoding) in combination with traditional ecological methods to establish the potential effects of Bti application on food web interactions. The study will be performed in Central Sweden, nedre Dalälven, where application of Bti has been ongoing since 2002.

Communication with a many different stakeholders is a central part of the study.