South American locust NSF Grant for RAPID Response Research
| South American locust NSF Grant for RAPID Response Research | |
|---|---|
 | |
| Project acronym: | RAPID |
| Status: | Completed |
| Project leads: | |
| Funding source: | National Science Foundation NSF |
| Project start: | 2018 |
| Project end: | 2020 |
| Keywords: | Nutrition, Ecology, Migration, Outbreaks |
| Species purview | |
| Species purview: | |
| Geographic purview | |
| Americas, Latin America and the Caribbean, Northern America, South America, Argentina, Uruguay, Paraguay, Bolivia, United States | |
| Associated resources: | |
Testing macronutrient imbalance as a key factor limiting range expansion in herbivores
Description
The South American Locust (Schistocerca cancellata) is experiencing the greatest population upsurge in 60 years. In 2017, large swarms left their small permanent breeding zone in NW Argentina and invaded Bolivia and Paraguay, and expanded throughout Argentina. The RAPID grant allowed researchers to collect time-sensitive data on locust macronutrient balancing in the field, which has emerged as a key factor in regulating insect behavior, physiology, and performance. We tested the hypothesis that S. cancellata in their expansion zones are unable to obtain food of sufficiently high carbohydrate:protein ratio to maximize their fitness.
Associated publications
| Title | Year published | Projects | DOI |
|---|---|---|---|
| Body Mass and Growth Rates Predict Protein Intake across Animals | 2024 | South American locust NSF Grant for RAPID Response Research | View |
| High carbohydrate diet ingestion increases post-meal lipid synthesis and drives respiratory exchange ratios above 1 | 2021 | South American locust NSF Grant for RAPID Response Research | View |
| Plant carbohydrate content limits performance and lipid accumulation of an outbreaking herbivore | 2020 | South American locust NSF Grant for RAPID Response Research | View |
Associated resources
No results found in the database at this time—please reach out if you have any to share!
Objectives
- What are the nutrient landscapes available to locusts in the outbreaking regions?
- How does the nutrient landscape affect the behavioral and physiological responses of the locusts?
- How does dietary protein:carbohydrate ratio affect migratory capacities?
- How does temperature affect locust performance and distribution?
Field work in Gran Chaco, Paraguay, April 2019
The field team gathered data on nutritional physiology and thermal biology with collaborators from Argentina, Bolivia, and Paraguay during continuing locust outbreaks in Paraguay.
Nutritional ecology
Most organisms have an ideal balanced diet (e.g. protein to carbohydrate ratio) that allows them to function optimally. Performance (survival and reproductive success) increases when an organism consumes close to the preferred protein-to-carbohydrate ratio.
In central Argentina and the edge of the locust’s range in Bolivia and Paraguay, most of the plants we sampled were protein-biased with protein:carbohydrate ratios greater than 1. During the Paraguayan field trip, we studied the behavioral and physiological responses in juvenile locusts collected from outbreak populations. Marching locust bands ate readily from dishes of carbohydrate-rich, but not protein-rich, diets. When given a choice, locusts selected a carbohydrate-rich diet with a protein:carbohydrate ratio of 1:2, grew and survived better on diets with higher carbohydrate content, and ate more of carbohydrate-rich plants. We confirmed these findings for lab-reared South American Locust (Schistocerca cancellata), enabling us to control for many environmental factors that may have occurred in the field. Plants or diets high in carbohydrate were necessary for locusts to accumulate sufficient fat to migrate. South American locust selected microsites that allowed them to maintain body temperatures near 40°C that maximized digestive performance, and modeling suggests that temperature affects the southern but not northern range limits of this species.
Outcomes
This RAPID supported postdoctoral, graduate and undergraduate student training, including providing the opportunity for one postdoc and one graduate student to work internationally during a locust plague.
Our results have informed pest management strategies by showing how different crops and/or natural vegetation assemblages affect locust performance. This information will allow managers to better target pesticides for specific locust populations. For example, locusts eating crops containing insufficient carbohydrate will be less viable, less able to migrate, and potentially more susceptible to pathogens, making fungal biopesticides a more feasible treatment option. Locusts are a major challenge for food security globally, with outbreaks causing up to 80-100% crop losses. By working with national plant protection organizations, this research can be directly applied to strategies to improve livelihoods, human and environmental health, and global food security.
Associated publications
| Title | Year published | Projects | DOI |
|---|---|---|---|
| Body Mass and Growth Rates Predict Protein Intake across Animals | 2024 | South American locust NSF Grant for RAPID Response Research | View |
| High carbohydrate diet ingestion increases post-meal lipid synthesis and drives respiratory exchange ratios above 1 | 2021 | South American locust NSF Grant for RAPID Response Research | View |
| Plant carbohydrate content limits performance and lipid accumulation of an outbreaking herbivore | 2020 | South American locust NSF Grant for RAPID Response Research | View |
Associated resources
No results found in the database at this time—please reach out if you have any to share!