The evolution of feeding behaviour

Question 1

What are search images?

Answer 1

Formed from specific queues of what an idividual is looking for.

Question 2

How did Tinbergen test search images?

Answer 2

• Tinbergen noticed that when a new type of caterpillar appeared in woodland breeding passerines didn’t immediately start feeding on them.
• Once a few were caught the birds then started catching them more frequently
• Formation of search image
• Set up specific queues to identify

Question 3

How did Pietrewicz and Kamil
show that blue jays formed search images

Answer 3

• Used operant conditioning to investigate if blue jays used search images to identify moths
• Search images were very quickly built up
• When moths changed - no search images (no single example)
• Increases capture rate with one species

Question 4

What are olfactory search images?

Answer 4

• Use sense of smell instead of vision
• Skunk example
• Distance of food detection increased as olfactory images increased
• Building up olfactory search image - remembering and improving over time

Question 5

Lizard foraging phylogeny

Answer 5

Lizard foraging phylogeny are either:

• Vision/ambush
• Olfaction/Searching

Question 6

Social insects: benefits and interactions

Social foraging: Isects, Birds and Mammals.

Answer 6

• Cooperation strongly favoured by kin selection
• Deliberately communicate with each other
• e.g. waggle dance, direct leading, pheremone trails.

Question 7

What are the benefits of foraging as a group?

Answer 7

• Take prey much larger than themselves
• Gather more food

Question 8

How did Karl von Frisch measure how bees indicated direction in the waggle dance?

Answer 8

• Firstly he used a Fan test & distance test.
• Secondly: Dance on vertical cones - angle from straight up to direction of waggle dance indicated which way recruits should fly is relation to the sun.
• By removing directional light from horizontal combs the directional information in the dances is removed.
• Directional information is very important to the bees

Question 9

How did Srinivasa show how bees measured distance?

Answer 9

• Image motion hypothesis
• More information that passes eyes the further they travel
• tested using different patterned tunnels
• Bees that flew down tunnels with more complex patterns thought they had gone a much further distance than those that hadn’t
• Bees were less likely to perform ‘round dances’ (which indicate a distance of less than 50m) when flying down patterned tunnels

Question 10

What is the fitness benefit of the waggle dance?

Answer 10

Colonies only benefit in winter when food is scarce

Question 11

Social foraging birds: Do Ospreys watch other birds in the colony to find fish?

Answer 11

• Test this by observing the comings and goings of ospreys
• Departure direction is random when none return with prey
• More departures in a single direction once an idividual returns with a prey

Question 12

Getting no help from companions: Do barn swallows follow the direction of successful foragers in the group?

Answer 12

• No
• The nature of the prey is very different
• Insects dont tend to stay in one place long enough for multiple predations.

Question 13

Group hunting in female lions

Answer 13

A behavioural adaptation to hunting large prey

Question 14

Creel and Creel measured net energy gain increase in african wild dogs. What did the study show?

Answer 14

• Net energy gained inceased in larger packs.
• Group hunting was beneficial as they didn’t expend as much energy