Locust Migratory Pathway Defined by Different Nutritional Diets

Migration allows animals to track favorable environments and avoid harmful conditions but is energetically costly. There are different types of migration, such as tidal/daily, seasonal, and lifetime. Locust migratory swarms are one such famous phenomena that can have dramatic effects on human livelihoods. During long-distance flight, locusts rely on lipid oxidation from fat stores, while initial flight is fueled by carbohydrates. However, limited studies have tested how dietary macronutrients affect insect flight performance. Therefore, we asked: How do different dietary macronutrient ratios affect prolonged flight migration? We predicted that high carbohydrate diets would lead to high body lipid synthesis which would increase flight performance. We reared locusts in three crowded cages from 5th instar to adulthood on artificial diet varying in p:c ratio, supplemented with lettuce and water tubes, ad libitum. We used 7-14-day old adult males for flight performance assays where each day we used new individuals for tethered flight for 12 h in wind tunnels (~12 km·h-1) and video recorded their flight. We found that locust flight duration and quality increased with a decrease of dietary p:c ratio. Using control groups of locusts, we estimated that across 1 day of flight (up to 12 h), locusts lost on average in all treatments ~25 or ~30% of their total body lipid content. We concluded that long distance flight is improved by a high carbohydrate and low protein diet for L. migratoria by increasing their fuel sources. This work was supported by NSF # 1942054.