Submission Type
Poster
Abstract
Cursorial arboreal organisms like ants face numerous challenges to their adhesive systems. Wind, rain, and the activities of vertebrates frequently dislodge foraging ants from tree surfaces. Falling is a significant hazard resulting in substantial displacement, thus ants are predicted to fully engage their tarsal adhesive systems when the likelihood of disturbance is high. Here we used a small catapult to experimentally test the effect of instantaneous red oak (Quercus rubra) leaf movement on the adhesive capabilities of Camponotus pennsylvanicus worker ants. Catapult velocity and displacement mimicked the effects of Eastern Gray Squirrel (Sciurus carolinensis) branch landings. Ants were either “primed” or “unprimed” during trials, where priming involved dropping a small pellet on the catapult arm to cause vibration ca. 1 s before launch. Trials were recorded at 240 frames s-1, and ant motion was quantified with NIH Image-J software FIJI package. We measured ant maximum height, initial velocity, and dry mass. Priming did not affect the average initial velocity or maximum height of launched ants. However, both variables were positively associated with ant mass. Contrary to our prediction, “primed” ants apparently do not enhance their adhesion to a leaf surface when a disturbance is imminent. These results illustrate the limited ability of ants to behaviorally avoid the consequences of a common natural hazard, and improve our understanding of the challenges imposed by an arboreal lifestyle.
Foraging Ants Dislodged via Simulated Instantaneous Leaf Movement
Cursorial arboreal organisms like ants face numerous challenges to their adhesive systems. Wind, rain, and the activities of vertebrates frequently dislodge foraging ants from tree surfaces. Falling is a significant hazard resulting in substantial displacement, thus ants are predicted to fully engage their tarsal adhesive systems when the likelihood of disturbance is high. Here we used a small catapult to experimentally test the effect of instantaneous red oak (Quercus rubra) leaf movement on the adhesive capabilities of Camponotus pennsylvanicus worker ants. Catapult velocity and displacement mimicked the effects of Eastern Gray Squirrel (Sciurus carolinensis) branch landings. Ants were either “primed” or “unprimed” during trials, where priming involved dropping a small pellet on the catapult arm to cause vibration ca. 1 s before launch. Trials were recorded at 240 frames s-1, and ant motion was quantified with NIH Image-J software FIJI package. We measured ant maximum height, initial velocity, and dry mass. Priming did not affect the average initial velocity or maximum height of launched ants. However, both variables were positively associated with ant mass. Contrary to our prediction, “primed” ants apparently do not enhance their adhesion to a leaf surface when a disturbance is imminent. These results illustrate the limited ability of ants to behaviorally avoid the consequences of a common natural hazard, and improve our understanding of the challenges imposed by an arboreal lifestyle.
Comments
Olivia M. Gamsky1, Andrew Seiler2, Alyssa Y. Stark3, and Stephen P. Yanoviak2,4,*
1Department of Environmental Science, Bellarmine University
2Department of Biology, University of Louisville
3Department of Biology, Villanova University
4Smithsonian Tropical Research Institute, Balboa, Republic of Panama