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Student 10-Minute Presentation

Physiology, Biochemistry, and Toxicology

Student

Student Competition

Grad 10-min Competition: PBT, Chemical Ecology and Toxicology

High protein diet increases susceptibility of desert locust, Schistocerca gregaria, to Metarhizium biopesticide infection

Monday, November 11, 2024
11:18 AM – 11:30 AM MST
Location: Phoenix Convention Center, 126 B, PCC
Oral Presentation Student Competition
Locusts are grasshoppers that exhibit density-dependent phase polyphenism and can migrate long distances in massive groups causing devastating impacts on agriculture. Fungal Metarhizium spp. biopesticides may be a viable alternative to synthetic chemical pesticides, however, challenges in their efficacy remain. One prior study showed that Australian plague locusts infected with Metarhizium consuming higher protein (p) to carbohydrate (c) diets mount a higher constitutive immune response than locusts consuming low p:c diets yet have lower survival rates. In contrast, another study showed that migratory grasshoppers eating either low or high p:c diets survived a Metarhizium infection longer than those eating a balanced 1p:1c diet, furthermore, fungal sporulation post-mortem only occurred on grasshoppers fed 1p:1c diets. We tested the effects of macronutrient balance on the ability of the desert locust, Schistocerca gregaria, to combat and survive Metarhizium infection. Infected and control final instar locusts were restricted to a carb-biased, protein-biased, or a balanced diet. We measured their phenoloxidase and prophenoloxidase activity, longevity, fungal sporulation and developmental time. Our results showed that infected locusts restricted to a protein-biased diet died sooner and had the most fungal sporulation, despite having higher phenoloxidase and prophenoloxidase activities. The mechanisms for these patterns are unclear, but possibly consumption of high protein diets by the Desert Locust enhances the nutritional status of Metarhizium.