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Human activities have altered nearly every major nutrient cycle across the globe with little understanding of the ecological consequences. These changes in nutrient availability have consequences that cascade through food webs and ultimately affect the abundance and richness of higher trophic levels. The tawny crazy ant (Nylanderia fulva), for example, is an invasive ant whose abundance is limited by calcium and stressed by sodium. Little is known, though, how the availability of micronutrients, which are less abundant in living tissue, can affect the fitness of consumers, especially invasive arthropods. To determine how changes in micronutrients affect the fitness of N. fulva, we collected 208 colonies of N. fulva and conducted feeding trials that manipulated the ratio of Ca:Na in food (by 10%, 25%, and 50%) in 2018 and 2019. Each colony contained 3 queens, 100 workers, and no brood (eggs, larvae, and pupae) at the beginning of the experiment. Colonies were maintained for 50 days, and at the end of the experiment, we counted the number of queens, workers, and brood and measured fresh colony biomass. After 50 days, we found that the Ca:Na ratio had little effect on the number of queens and workers, as they were similar across all treatments; however, colony biomass increased with increasing amount of Ca in the diet, while biomass decreased with increasing amounts of Na in the diet. These results indicate that these changes in colony biomass may be due to a change in the number of brood or worker size, and that Ca is an important factor regulating the success of N. fulva. Our results support growing evidence that micronutrients may be important for structuring arthropod communities, and that Ca may help to facilitate the spread of an invasive ant.
Chelse M. Prather
Primary Advisor's Department
Stander Symposium project, College of Arts and Sciences
United Nations Sustainable Development Goals
Life On Land
"Just Like You, Invasive Ants Diet Too: How Do Micronutrients Affect Colony Fitness in Tawny Crazy Ants?" (2020). Stander Symposium Projects. 2004.