Non-traditional management of Melanoplus sanguinipes, a major rangeland grasshopper pest: Nutrition, temperature, and biopesticides past and present: A dissertation overview

Melanoplus sanguinipes is one of the most economically destructive grasshoppers in the U.S., with populations often emerging in rangeland habitats and migrating to croplands miles away. Through approaches including nutritional physiology, immunology and biopesticides, and more qualitative methods, this dissertation focuses on advancing our understanding of new methods to improve biological control strategies. First, we examined the nutritional physiology and ecology of lab and field populations of M. sanguinipes and found that field populations self-selected carbohydrate-biased diets that match their nutritional landscape, while lab populations self-select more balanced diets. Next, we examined the combined effects of prescribed fever and Metarhizium infection on survival and intake targets. We discovered infected M. sanguinipes specimens did not shift their intake target compared to control groups, but all groups were carbohydrate biased. We also found that infected grasshoppers had higher survival rates when behavioral fever was simulated. Follow-up experiments will further examine how prescribed diets/fever affect survival during various Metarhizium challenges. Finally, we will complement the field and lab research with a meta-analysis of non-traditional grasshopper management methods to better understand their strengths and challenges, as well as surveys aimed at assessing stakeholder perceptions and knowledge on these alternative methods. Biopesticides have been in use for decades, but much research is still needed to understand how they interact with other variables, such as nutrition and temperature, and more work with stakeholders is needed to identify barriers and opportunities for implementation.