The Influence of home range markings on the search behavior of ants
Stefan Michael Popp, Stefan Michael Popp , Rowen Waimea Stokes , Jiadong Yu , Anna Dornhaus
Ecology & Evolutionary Biology, University of Arizona, Tucson, Arizona, USA; Ecology & Evolutionary Biology, University of Arizona, Tucson, Arizona, USA ; Physiology, University of Arizona, Tucson, Arizona, USA ; Psychology, University of Arizona, Tucson, Arizona, USA ; Ecology & Evolutionary Biology, University of Arizona, Tucson, Arizona, USA
When ants walk over a surface they passively deposit long chained hydrocarbons stemming from specialized glands on their tarsi. These ‘footprint pheromones’ mark the home range or territory of an ant colony. Such home range markings (HRMs) help colony members navigate and home. However, their role in modulating the search behavior for new resources has rarely been investigated. In this current experiment, I test the impact of HRMs on the geometry of movement paths by comparing the dispersiveness and path tortuosity between ants walking on a home range marked surface versus a pheromone free surface. I let ants freely explore a large arena over 5 days, allowing them to build up home range markings on a paper covering the entire floor. After 5 days, I change the paper cover, creating a HRM-free surface. I calculate the mean squared displacement, as a measure of dispersiveness, and sinuosity, indicating how much the ant turned per distance, from video recordings of the arena. Preliminary results suggest that ants show more dispersal and straighter paths near the nest when walking on a home range marked surface. If this relationship holds true with more data, it indicates that ants use HRMs as signals modulating their search behavior based on their distance from the nest. Thus, in areas close to the nest, where many nestmates have walked before and deposited HRMs, ants are less likely to search intensely. However, more data and analyses will certainly bring more equally interesting results and novel insights in the movement behavior of ants and the influence of passively deposited pheromones.