Comparative Mortality and Adaptation of a Smurf Assay in two Species of Tenebrionid Beetles Exposed to Bacillus thuringiensis

• Published in: Insects (Basel, Switzerland) Switzerland), 2020-04, Vol.11 (4), p.261
• Main Authors: Zanchi, Caroline, Lindeza, Ana Sofia, Kurtz, Joachim
• Format: Article
• Language: English
• Subjects: Adaptation; Assaying; Bacillus thuringiensis; Bacillus thuringiensis tenebrionis; Bacillus thuringiensis tolworthi; Beetles; Binding sites; Biopesticides; Digestive system; Disintegration; Epithelium; Exposure; Flour; Fruit flies; Gastrointestinal tract; Infections; Ingestion; Insects; Laboratories; Larvae; Leakage; Midgut; Mortality; Oral administration; oral infection; Sepsis; Smurf assay; Species; Tenebrio molitor; Tribolium castaneum; Virulence; Virulence factors
• ISSN: 2075-4450; 2075-4450
• DOI: 10.3390/insects11040261

is a spore-forming bacterium which infects insect larvae naturally via the oral route. Its virulence factors interact with the epithelium of the digestive tract of insect larvae, disrupting its function and eventually leading to the death of susceptible hosts. The most cited killing mechanism is the extensive damage caused to the insect midgut, leading to its leakage. The mortality caused by has been shown to vary between serovars and isolates, as well as between host life stages. Moreover, whether susceptibility to -induced gut leakage is generalized to all host species and whether there is individual variation within species is unclear. In this study, we adapted a non-invasive "Smurf" assay from to two species of tenebrionid beetles: The mealworm beetle and the red flour beetle , during exposure to . We highlight a differential mortality between two age/size classes of larvae, as well as different killing dynamics between var. and var. in . The Smurf assay did not reveal a high occurrence of extensive gut disintegration in both host species upon ingestion during exposure.