1. Leafcutter AntsAusten Hilding, Zoe Gerber, Kat Kurtenbach,Theresa Thao Nguyen

2. Atta cephalotesAusten Hilding, Zoe Gerber, Kat Kurtenbach,Theresa Thao Nguyen 3. Optimal Foraging Theory Organisms forage in a way that maximizes energy intakeper unit of time (most calories in least amount of time) A trade-off between: energy used and energy gained time foraging and time being vigilant Maximizes fitness Minimize energy exerted Equation:Eaverage / (haverage + saverage)E = Energy, h = handling time, s = search time 4. In other animals The Optimal Foraging Theory has also been appliedto copious amounts of other species to explore andexplain behavioral patterns Ex: A study assessed the optimal foraging decisionsfor the common crow, Corvus caurinus, in catchingJapanese-little-necked clams. Finding these clamsrequires the crow to probe in the sand for anaverage of 34.6 seconds. The results of the studyshowed that the best foraging strategy was forcrows to wait to consume clams above 28.5mmrather than waste energy on smaller clams that areless profitable. 5. Natural History of Leafcutter Ants Ants collect leaf fragments and create a mulch tocultivate a fungus garden Ants are separated into different castes depending onsize Soldiers guard the entrance to the nest or scout forpredators Workers (all female) consist of media and minima Media with powerful jaws cut the leaves and returnthem to the nest Minima prepare the leaf fragments to be fed to thefungus garden Ants are able to navigate between the source of leavesand the nest in a process called tandem running 6. Why these leafcutter ants wereconvenient for measuring OFT Prey (in this case, leaf fragments) were consistent No toxins No variability Trails are visible Can manipulate biomass Numerous amount of this species available toexperiment on Ants choose & cut the leaf fragments themselves(i.e. making the most optimal choice) 7. Question & Prediction Whether the ants are choosing the mostefficient leaf fragment size to maximizeenergy intake while minimizing energyexerted. So if the optimal foraging theory applies,then these ants should be transporting themost optimal size of the leaf fragment thatwould carry the most biomass to the nest atthe most efficient rate. 8. MeasureWeight of leaf fragments ControlWeight reducedWeight added Measure carrying speed of 20cm ControlWeight of reduced/added 9. Materials Stopwatch Tweezers Scale Tape Measure Scissors (to cut leaf fragment) Foil to add weight to create a burrito for the ant toprevent them from moving!) 10. Our Methods 11. Measure 20cm 12. Time 13. Control Ants 14. Ants w/ weight reduced 15. Ants w/ foil Added 16. 30 ants per treatment 17. Remove all minima!!!! 18. Weigh on Scale Ants Leaf fragment Reduced LeafFragment Tin foil#Richard 19. RecordData(& tryto looksmart) 20. Results14121086420Reduced Whole(Sec)t = 3.018, df = 30,p-value = 0.0051 (significant) 21. ResultsEfficiency (g/sec)t = 4.21, df = 30,P-value = .00022 (significant) 22. ResultsFoil Leaf(Sec)t = -4.32, df = 29,p-value = .00016 (significant) 23. ResultsEfficiency (g/sec)t = -1.71, df = 29,p-value = .098 24. Discussions According to our results, ants carrying a reduced size of theleaf fragments were not foraging as optimally as thosecarrying the original size fragments. However, ants carrying leaf fragments with added weight (i.e.foil) were foraging as optimally or more as those carrying theoriginal size fragments. Possible reasons why leafcutter ants do not carry moreweight: Area factor Distance factor Prey factor Environment (ex. wind) factor 25. Thank you! 26. Really 27. Ya know?