Hilborn & Mangel: c. 4-7, 10-11
Studies of animal (and more recently plant) foraging behavior/strategies is an area of ecological research that has been both fruitful and full of controversy. Simply stated, one observes that organisms need to eat in order to survive and reproduce. One could conclude, therefore, that evolution should favor those organisms most 'efficient' in gathering resources. (Efficiency can be defined in many ways: minimal handling time of resources; maximum use of any given resources [little waste]; speed of gathering of resources; etc.) This observation leads to the hypothesis that organisms should forage (i.e. gather resources) in some 'optimal' way that reflects the best possible (evolutionary) solution to the problem of gathering food while simultaneously dealing with everything else that an organism has to deal with (finding shelter, mates; avoiding predators; etc.). The literature addressing this hypothesis is vast. Chapters 4-7 and 10-11 in Hilborn & Mangel (1997) provide general background on predation and foraging. A collection of papers in the lab provide good background information on optimal foraging theory and experiments (MacArthur and Pianka 1966, Schoener 1971, Charnov 1976. Stearns and Schmid-Hempel 1987). A critique of these models is also included in the lab binder (Pierce and Ollason 1987). Do you see anything obviously wrong with the proposed hypotheses?
Your objective in the next three weeks is to attempt to experimentally test the hypothesis that organisms forage in an optimal way. Working together in small groups (2-4 students), you should formulate your own hypothesis to test (certainly more narrowly construed than described above), choose the organism for the experiment, design the experiment, and do it. I will provide advice, counsel, and logistical support to the extent that our equipment, facilities, and budget permit. This lab is deliberately open-ended and ill-defined. This is the sort of thing that all practicing ecologists do when confronting a new problem.
October 4: You should use the first part of the lab time to think about optimal foraging theory, look at some of the articles, develop your testable hypothesis(es), figure out your methods in detail, and make a list of necessary equipment and/or organisms. For legal and bureaucratic reasons, I prefer that you do not work with vertebrates in the lab; if you want to observe birds or squirrels outside, that's ok, though. Around 3:00, we'll go over your hypotheses and methods, and I will help you get together any necessary equipment and order any organisms, if necessary.
October 11: This session is open; you can use it for continued experiment time, discussion of difficulties so far encountered, etc. This is the latest date on which you should begin doing your experiments. Be prepared for things not to work! and be willing to modify your design accordingly. Experimental work can (and probably should) continue during this week.
October 18: Experiments should be complete by this date. The lab session will be used for discussing data analysis, problems and solutions.
October 25: Write-up due.
You should write up the results from this lab in standard format, in no more than 10 pages. The introduction and discussion of your lab report should reflect your research into, and reading of, the primary ecological literature on optimal foraging. You should clearly state your hypothesis in both the abstract and in the introduction. The methods should completely describe your experimental design. Your results should reflect careful analysis relevant to testing your hypothesis and they should be clearly and concisely presented.
Charnov, E. L. 1976. Optimal foraging, the marginal value theorem. Theoretical Population Biology 9: 129-136.
MacArthur, R. H., and E. R. Pianka. 1966. On optimal use of a patch environment. American Naturalist 100: 603-609.
Pierce, G. J. and J. G. Ollason. 1987. Eight reasons why optimal foraging theory is a complete waste of time. Oikos 49: 111-118.
Schoener, T. W. 1971. Theory of feeding strategies. Annual Review of Ecology and Systematics 2: 369- 404.
Stearns, S. C. and P. Schmid-Hempel. 1987. Evolutionary insights should not be wasted. Oikos 49: 118-125.