1. Light level as an environmental cue for foraging in Red Harvester Ants Zoe Henrichs & Matt Brown

2. Test Organism Pogonomyrmex barbatus

3. Purpose & Hypothesis Investigation into the environmental cues influencing foraging behaviour and activity. To test light level as foraging inducer Hypothesized most activity would be seen in starved ants under brightest light.

4. Materials & Methods Ants kept under 24-hour dark cycle. Red light used as control Timed ants dispersal to the other end of chamber under varying light intensities 10 trials at every intensity, 5 minute limit

5. Results Mean time of starved vs. non-starved groups at varying light intensities

6. Results

7. Starved vs Non-starved Non starved Starved

8. Discussion Results contradicted hypothesis (Denebourgh, Depickere and Fresneau 2004) Slower mean times at high light intensity No even distribution of results Overlap in SD Variance of results Small sample number

9. Discussion Ways to improve future studies Control temperatures (Cole et al 2013) Separate brood-tenders and foragers (Deneubourg, Depikere and Fresneau 2005) Stimulation - trail laying and interaction (Bala et al 2013) Many unknowns Effects of environmental cues aren’t widely studied Climate change and preservation

10. Time to complete trial (red vs normal light)

11. % failing to complete the trial

12. References Bala A, Gordon D, Holmes S, Merrell A, Stumpe M, Queirolo J, Pinter-Wollman N. 2013. Harvester ants use interactions to regulate forager activation and availability. Animal Behavior. 86.197-207 Cole B, Huber Z, Smith A, Wiernasz D. 2009. The structure of foraging activity in colonies of the harvester ant, Pogonomyrmex occidentalis. Behavioral Ecology. 21. 337-342. Deneubourg J., Detrain C., Mailleux A. 2005. Triggering and persistence of trail-laying in foragers of the ant Lasius niger. Journal of Insect Physiology. 51. 297-304. Deneubourg J., Depickere S., Fresneau D. 2004. The influence of red light on the aggregation of the ant Lasius niger. Journal of Insect Physiology. 50. 629-635. Gordon D. 2001. Ants at work: how an insect society is organized. Philosophy of Science. 68. 268-270. Hemmi J, Narendra A, Reid S. 2010. The twilight zone: ambient light levels trigger activity in primitive ants. Royal Society B: Biological Sciences. 227: 1531-1538.

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