The Social Symphony of Treehoppers: Cooperative foraging dynamics in two species, Enchenopa binotata and Tylopelta giberra, and an in-depth analysis of rapid movement-induced vibrational cues of Mimosa pudica

Group living organisms rely heavily on cues and signals from other group members to make decisions. I studied how foraging decisions are influenced by communication in two species of plant-feeding insects that differ in ecology and life history. I also studied the cues produced when leaves of sensitive plants temporarily stop foraging for light. In treehoppers, I hypothesized that recruitment signals would guide the choice of feeding sites by group-living immatures. Both species engage in a food-for-protection mutualism with honeydew harvesting ants, and I found that ant bodyguards are more likely to be present when individuals are feeding in larger groups. I first characterized the context in which nymphs produced plant-borne vibrational signals, then experimentally tested the influence of those signals on the foraging decisions of other nymphs. I found that communication underlies cooperative foraging in both species but using different signals and signaling dynamics. In one species, searchers initiate back-and-forth exchanges with individuals already at a feeding site, while in the other, settled individuals produce series of collective signals that act as a beacon. In sensitive plants, I found that leaf-folding produces distinctive vibrational cues, which have the potential to influence the light-foraging decisions of neighboring leaves and the movement decisions of other organisms on the plant. The discovery of vibrational signals that underlie cooperative foraging in treehoppers, and of incidental vibrational cues that accompany leaf-folding in sensitive plants, sheds light on an overlooked aspect of information exchange among organisms.  

Doctoral Program Committee

Dr. Rex Cocroft
Dr. Debbie Finke
Dr. Manuel Leal
Dr. Johannes Schul

Publications

Michael, S.C.J., Patman, J. & Lutnesky, M.M.F. Water clarity affects collective behavior in two cyprinid fishes. Behav Ecol Sociobiol 75, 120 (2021). https://doi.org/10.1007/s00265-021-03060-x

Michael, S.C.J., Appel ,H.A., Cocroft, R.B. Methods for Replicating Leaf Vibrations Induced by Insect Herbivores. Methods Mol Biol. 2019;1991:141-157. doi: 10.1007/978-1-4939-9458-8_15. PMID: 31041771.

Patman, J., Michael, S.C.J.,  Lutnesky, M.M.F., Palaniappan, K. BioSense: Real-Time Object Tracking for Animal Movement and Behavior Research. 2018 IEEE Applied Imagery Pattern Recognition Workshop (AIPR), Washington, DC, USA, 2018, pp. 1-8, doi: 10.1109/AIPR.2018.8707411.