How Does an Invasive Ant, Nylanderia Fulva, Affect Prairies?

Date of Award

2021

Degree Name

Ph.D. in Biology

Department

Department of Biology

Advisor/Chair

Chelse Prather

Abstract

Invasive species are a global threat that cause major ecological and economic harm, as they are a major contributor to loss of biodiversity and ecosystem function. Introduced ants becoming increasingly ubiquitous in terrestrial ecosystems and some of the most destructive invaders can extreme numerical densities, displace native ants and non-ant arthropods, and as a result, can alter the structure and function of natural ecosystems. A recent invader of emerging importance, the tawny crazy ant, Nylanderia fulva (Hymenoptera: Formicidae), is highly successful in coastal ecosystems in the Southeastern United States. We investigated the causes and consequences of invasion by N. fulvaon coastal tallgrass prairies by determining: 1) diet, trophic position, and their potential to affect large, aboveground insects; 2) the effect of invasion on native above- and belowground insect communities; 3) the factors that limit N. fulvaabundance; and 4) the mechanisms of N. fulva nutrient limitation and stress. In summary, N. fulva is an omnivorous ant that obtains most of its nitrogen from plants but has the capabilities to attack and kill large aboveground arthropods, like grasshoppers. In recently invaded habitats, N. fulva invaded areas were associated with lower native ant and grasshopper abundance, but these areas also contained greater abundances of hemipteran mutualists, which likely contribute to their extreme densities and success. Additionally, in litter communities, N. fulva numerically dominated the composition of litter-dwelling arthropods, and their abundance was limited by the availability of calcium but tended to be stressed by increased concentrations of potassium and sodium in the soil. Colonies of N. fulva that were fed diets with increased levels of calcium showed the ability to increase colony biomass. Based on these findings we show the great potential of this invasive ant to rapidly decrease the abundance and richness of native arthropods, which could have long-term negative impacts on native biodiversity, and show the factors that allow this invasive ant to reach numerical dominance in invaded ecosystems.

Keywords

Ecology, Biology, Entomology, invasive ant, tawny crazy ant, coastal tallgrass prairie, grassland, stable isotope, invasion front, nutrient limitation, macronutrient, micronutrient, calcium, sodium

Rights Statement

Copyright © 2021, author

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