Toxins of Bacillus thuringiensis subsp. israelensis (Bti) are safer alternatives for controlling dipteran pests such as black flies and mosquitoes. The biting midge Culicoides sonorensis (Diptera: Ceratopogonidae) is an important pest of livestock in much of the United States and larval midges utilize semi-aquatic habitats which are permissive for Bti product application. Reports suggest that Bti products are ineffective at killing biting midges despite their taxonomic relation to black flies and mosquitoes. Here, we investigate the toxicity of a Bti-based commercial insecticide and its active ingredient in larval Culicoides sonorensis. A suspected mechanism of Bti tolerance is an acidic larval gut, and we used a pH indicator dye to examine larval Culicoides sonorensis gut pH after exposure to Bti.

中文翻译：

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肠道 pH 值变化是苏云金芽孢杆菌亚种耐受的潜在机制。声蚊库蠓中的以色列毒素

苏云金芽孢杆菌亚种毒素。israelensis ( Bti ) 是控制黑蝇和蚊子等双翅目害虫的更安全的替代品。咬蠓Culicoides sonorensis（双翅目：Ceratopogonidae）是美国大部分地区的一种重要牲畜害虫，幼虫利用半水生栖息地，这使得Bti产品的应用成为可能。报告表明，尽管Bti产品与黑蝇和蚊子有分类学关系，但它们无法有效杀死叮咬蠓。在这里，我们研究了一种基于Bti的商业杀虫剂及其活性成分对库蠓幼虫的毒性。Bti耐受的一个可疑机制是幼虫肠道呈酸性，我们使用 pH 指示剂染料来检查幼虫接触Bti后库蠓的肠道 pH 值。