Concepts:

1. Foraging behavior
2. Optimizing time spent foraging
3. High quality vs. low quality environments

Skills:

1. Optimal Foraging Behavior
2. Formation of Foraging Strategies
3. Point-system Calculations
4. Group Data Collection

Information:

1. Animals' Reaction and Adjustment to Environmental Conditions
2. Behavioral Plasticity Based on Current Conditions
3. Strategies for High Quality Foraging and Low Quality Foraging

1. Students will successfully "forage" for food items.
2. Students will change foraging strategies as environmental conditions change.
3. Students will understand why certain strategies should be favored over others.
4. Students will understand the relationship between optimal foraging and current ecological conditions that animals face on a daily basis.

1. 300 small dixie cups (must be opaque, as they will hide food items from view)
2. 3 types of candy treats, preferably of clear increasing quality (i.e. a Reeses cup is clearly better nutrient-wise than a plain M&M, a Reeses and a peanut M&M is a little trickier)
3. Large foraging areas (benches are better than desks)
4. Handout

Procedure

Opener

Students should be broken down into 3 groups, consisting of 3-4 students per group (6 groups is okay for a larger class). Before students arrive, stations should be setup at the laboratory benches, so that there are 3 stations of 100 cups each when students arrive. For our activity, I labeled these stations (New England, Georgia, and Brazil, however you may choose any names you'd like). The 3 stations should vary in quality, but not quantity, of food items (i.e.warmer climated have bigger, nutrient-rich insects, however, this may not be true year-round). In our case, New England was a poor site to forage in, while Brazil was a high quality site, and Georgia was somewhere inbetween.
Place aproximately 50 food items at each of the stations, but keep the number equal for each station.

For the high quality site, for example, put:

25 Reeses Cups or equivalent
15 Plain M&Ms or equivalent
10 Skittles or equivalent

For the medium quality site, put:

10 Reeses Cups or equivalent
25 Plain M&Ms or equivalent
15 Skittles or equivalent

For the low quality site, put

10 Reeses Cups or equivalent
15 Plain M&Ms or equivalent
25 Skittles or equivalent

You may exaggerate these differences even further, as long as you keep the NUMBER of food items identical. This way, all foraging decisions are made based on food quality alone, and are not based on food quantity. You may also change the quantity for some really exaggerated effects.

Development

Give the students the handout provided HERE: Students should be interested in the stations as they walk into the classroom, ensure that they don't peek under the cups before the first trial begins. Have each group start at a station and have one student from each group start off as a forager (one student should be a timer and the other a data recorder).

Students will, at ten second intervals, move to new foraging areas (cup) as they move around their station. Students can start at any cup intially. Then, after each ten second interval, they may move to any area adjacent to the area they just visited. If a food item is found, and the forager decides to keep it, they must incur a ten-second penalty (to process the food item). If they decide to not take the food item, they may move on to a new foraging area at the next switch. Obviously, if there is no food item under the cup, the forager may move on at the next switch. Continue foraging for a 3-5 minute period, then have students switch stations (and foragers). During the last run, let students keep all of the candy they pick up during their foraging!

Closure

Students should, by the end of the laboratory, clearly understand the role that environmental conditions play in determining the optimal foraging behavior for a particular organism. In poor quality habitats, foragers must take every food item they can find, as there are too few high quality items to search for exclusively. In other words, foragers must be GENERALISTS, a term describing a foraging strategy that encorporates a wide diet breadth, such that nutrient requirements may be met despite the lack of many high quality habitats. In contrast, in high quality habitats, foragers can opt to be quite choosey, not wasting time and energy on low quality items and instead focusing on the very abundant high quality ones. These organisms are SPECIALISTS, and are often found in high quality habitats, such as those found in tropical rainforests. With many organisms foraging in this manner, competition may be reduced (as each species may specialize in a different food item) and the habitat or ecosystem may be able to support more species as a whole (this is a somewhat debated hypothesis for the reason we see so many more species as we move closer in latitude to the equator). Feel free to discuss this with students and get their opinions about this topic. What are some other possibilities for the increase in species number?

Students can be asked a variety of questions:

See handout for evaluation questions

Below are several links explaining optimal foraging in more detail. Depending on how advanced the students are, you may want them to explore how optimal foraging can be explained mathematically, and how quanitites such as diet breadth can be calculated using real foraging bouts. Squirrels make great study subjects for optimal forgaing laboratories outdoors, as they are readily observed and are often hungry! Peanuts and seedless grapes are food items that may be used for these types of studies, and depending on the season, results may vary according to moisture content of the food items. There are a number of hypotheses that may be explored using this simple biological system.

http://www.cquest.utoronto.ca/zoo/bio150y/foraging/ (a similar computer-based version of optimal foraging lab)

http://eebweb.arizona.edu/Animal_Behavior/links/links_optimal.htm

http://www.biodiversity.nl/encyclopedia.htm