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- All Subjects: Physiology
- Creators: Harrison, Jon
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.
Before developing a theory for all animals, a model needs to be developed for a single model animal, such as fruit flies, that can be used to empirically examine how organisms thermoregulate under competition. My work examines how flies behave around other flies and develops a game theory model predicting how they should optimally behave. More specifically, my research accounts for competition among larvae by using game theory to predict how mothers should select sites when laying eggs. Although flies prefer to lay their eggs in places that will offer suitable temperatures for the development of their larvae, these sites become less suitable when crowded. Therefore, at some density of eggs, cooler sites should become equally beneficial to larvae when considering both temperature and competition. Given this tradeoff, an evolutionarily stable strategy (ESS) emerges where some flies should lay eggs in cooler sites while other flies should lay eggs at the warmer temperature. By looking at the fitness of genotypes in habitats of differing quality (competition, temperature, food quality, space), I modeled the ESS for flies laying eggs in a heterogeneous environment. I then tested these predictions by observing how flies compete for patches with different temperatures.