Biology 484 – Ethology

Chapter 7 – The Evolution of Feeding Behavior

Chapter 7 Opener: A bullfrog has many dietary choices to make

The Common Whelk (or Snail)

7.1 Optimal foraging decisions by northwestern crows when feeding on whelks

The maximum cost/benefit ration is seen at the arrow.

7.2 Available prey versus prey selected

Why would they not select the LARGEST mussels?

7.3 Two optimal foraging models yield different predictions

7.5 A foraging bout by the red knot

Time line showing how the bird will select to move to another foraging spot.

7.6 Young garden skinks lower their foraging success in order to reduce the risk of predation

Feeding behavior can be influenced by other risks, such as that of predation pressures. In this case, it is snake scent.

This is an image of the phorid fly on the left. On the right is the end result of an attack on a fire ant, the main food item of this fly.

7.7 Foraging efficiency is compromised when the risk of predation is high

The forager ant is preyed upon by the phorid fly. But the phorid fly will only consume insects with a head size of 1.8 mm or greater. Hence, during predation times, the forager ant only sends out smaller (less efficient foragers).

7.8 Records of energy consumption in relation to trotting (red line) versus galloping (green line)

Look for the efficiency of trotting versus galloping.

7.9 How can two hereditary phenotypes coexist in the same population?

7.10 Two hereditary forms of an African cichlid fish

Because their phenotype differs, the two forms do not compete for resources.

7.11 The results of frequency-dependent selection in Perissodus microlepis

7.12 Do osprey nesting colonies serve as information centers? (Part 1)

7.12 Do osprey nesting colonies serve as information centers? (Part 2)

7.14 Web ornament of an orb-weaving spider

Web ornamentation is seen in the more reflective regions (the zig-zag patterns) seen in this web.

7.15 Do web ornaments lure prey?

7.17 A cost of conspicuous web decorations?

7.19 The antimicrobial properties of the major spices

7.20 Clay eating has evolved in several species of parrots

Clay eating is useful for dissipating toxins the birds consume.

7.21 Round dance of honey bees

7.22 Waggle dance of honey bees (Part 1)

7.22 Waggle dance of honey bees (Part 2)

7.23 Testing directional and distance communication by honey bees (Part 1)

Test by von Frisch examining ability to learn direction from the dance in bees.

7.23 Testing directional and distance communication by honey bees (Part 2)

Test by von Frisch to test the communication of distance by the dance language in bees.

7.24 Honey bee recruits really do “read” the symbolic information in dances

The blue bees were trained to think the food source was 70 meters away.

7.25 Rapid buildup of recruited foragers at flower patches after discovery by scout bees (Part 1)

7.25 Rapid buildup of recruited foragers at flower patches after discovery by scout bees (Part 2)

7.26 The adaptive value of the dance communication system (Part 3)

Note especially how the bees in the winter benefit especially in enviornments with oriented (unipolarized) light.