Assignment 1 -

1) Suppose a bird has the potential to encounter two seed types.

Moonflower seed is encountered every 8 minutes, takes 3 minutes to handle and is 100 calories.

Evening Glory seed is encountered every 6 minutes, takes 4 minutes to handle and is 150 calories.  

a) Which seed is more valuable?

b) Should the bird specialize on one of the two seeds? If so which one?

2) Suppose prey 1 takes 8 minutes to handle, and is 60 calories. Prey 2 takes 10 minutes to handle, is encountered every 12 minutes and is 30 calories. What would be the minimum encounter rate for prey 1 in order for the predator to include prey 2 in its diet?

3) Suppose a Ladybird Beetle can encounter 2 aphids. The spider moves at 10 cm/sec.

Green Aphid: takes 3 minutes to handle and is 9 calories

Yellow Aphid:  takes 5 minutes to handle and is 15 calories

The green aphids are found at 8 aphids/cm² and the yellow aphids 3/cm².

Should the Beetle specialize on one of the two aphids? If so which one?

4) Suppose a Bass has the potential to encounter three prey items.

Crayfish: encountered every 6 minutes, takes 7 minutes to handle and are 25 calories.

Frogs:  encountered every 10 minutes, takes 3 minutes to handle and are 24 calories.

Minnows: encountered every 3 minutes, takes 3 minutes to handle and are 28 calories.

Given these three prey items, what would be the optimal diet for the predator?

5) You encounter a cave system which contains a pool of water. The pool only contains blind fish and their two prey items, cave shrimp and cave midge larvae. You are curious if the fish are following the optimal diet model. You measure the caloric value of the prey items, the handling times, the density of the prey, and the speed of the fish. You also observe what the fish eat. 

The data set can be found in an excel file on-line.  Based on these results are the fish following the optimal foraging model? Be sure to justify your answer. 

 6) The graph below represents the rate of resource intake from Patch A (Solid black line) and Patch B (Dotted Grey line). There are only 2 patches. The forager moves back and forth between the patches. When the forager is gone the patch resets.  

a) If the travel time between patch A and Patch B is 30 minutes. How long will the forager stay in Patch A before moving on? How long will it stay in Patch B?

b) Will the forager stay longer in Patch A or Patch B? Why?

c) If the forager stays in patch B for 15 minutes before leaving for patch A, How long will it stay in Patch A before moving back to Patch B?

Assignment 2 -

1) Below are three graphs containing the feeding results for three different species fed several foods with different ratios of lipid to protein. The "+" indicates the intake target for the species and the dots are results for individual food types. There is a PowerPoint posted for this problem set that reviews the different scenarios we discussed in class. Based on those, explain the results for each of the species below. 

2) In an experiment, Fiddle Crickets were given access to two different food sources with different carbohydrate and protein ratios. In trial 1, 10 crickets were put in individual containers. Each cricket was given access to a food source that was 5% carbohydrates: 10% protein and another food source that was 10% carbohydrates: 5% protein. The amount (mg) of each food consumed was measured. The second trial was set up the same way as the first trial except 10 different crickets (to avoid the effects of satiation) were used and they were given access to foods containing 10% carbohydrates: 20% protein and  20% carbohydrates: 10% protein. The results are in the excel file that accompanies this assignment. Base don't the data determine at the intake target for the Fiddle Cricket.

Attachment:- Assignment.rar