Scavenging ant foraging behavior and variation in the scale of nutrient redistribution in semiarid grasslands

TitleScavenging ant foraging behavior and variation in the scale of nutrient redistribution in semiarid grasslands
Publication TypeJournal Article
Year of Publication2003
AuthorsBestelmeyer BT, Wiens J.A.
JournalJournal of Arid Environments
Date PublishedMarch 1, 2003
ARIS Log Number131539
AbstractThe scavenging of arthropod carrion by ants is an important mechanism of nutrient redistribution in grasslands. But, the foraging activities of scavenging ants have been scarcely documented. We examine variation in overall ant foraging activity among grassland regions differing in species composition and how this creates differences in the distances that scavenged material is redistributed among three semiarid grassland ecosystems. In order to consider the effects of the ant community as a whole on the disposition of nutrient resources, we focused on the fate of baits that appeared under different environmental conditions. Specifically, we asked 1) which ant species are the dominant scavengers in each grassland, 2) what ant characteristics determine the distance that baits are removed to nests, and 3) how do these patterns come together to create differences among grassland ecosystems in the distance that scavenged resources are removed? Species at a site differed widely in the microclimatic conditions that they removed baits and in the average distances they were removed. Generally, species with large-bodied workers and thermophilic species removed baits the farthest. Overall, this resulted in a positive relationship between removal distance and vapor pressure deficit (VPD). Controlling for intersite variation in habitat types and VPD, mean removal distance across all ants increased from the shortgrass steppe to the Chihuahuan Desert grassland. We conclude that differences in the foraging ecology and body size of the dominant scavengers among these grasslands can create a seven-fold variation in the spatial scale of nutrient concentration by ants. These species are little-known when compared to the harvester ants emphasized in ecosystem studies.