5.For robins small worms contain 25 calories of
energy, cost 10 calories and take 2 minutes to harvest. For the same birds medium worms contain 50
calories and cost 15 calories and take 3 minutes to harvest. Large worms contain 75 calories, cost 30
calories and take 5 minutes to harvest.
Based on optimal foraging theory, what sized worms should robins
favor? Explain your logic!
The optimal foraging theory states, that in order to
maximize the overall amount of energy gain, the prey is chosen by the
following: if E – is energy value and h - is
prey handling time, the choice will be with whichever will have higher
- energy/handling time value. For small worms the ratio will be (25calories-10calories)
/ 2 minutes = 7.5, form medium worms the ratio will be (50calories – 15calories)/3minues
= 11.7 and for large worms, the ratio will be (75calories-30calories)/5 = 9.
Therefore it is clear that medium worms have the highest
energy / handling time value and should be robins' first choice, then large-sized worms and the last are small worms,- due to the above mentioned reasons.