Ch7 Trade-offs and Cost of Signaling

Question 1

Physiological cost

Answer 1

production of signals involves cost. Energetic and physiological investments.

Question 2

Eavesdropping

Answer 2

can gain information about rivals and adjust their display accordingly. Predators use cues like rustling leaves to detect prey, but communication signals may also get exploited.

Question 3

Tungara Frogs

Answer 3

T.Frogs have a specific call that has two components (whine and chuck). They wine when they are alone and whine + chuck when there are other males around. Bats capture frogs using their calls as cues to localize them. Success rate for catching frogs with complex calls is higher than when there is no frog calling. Complex calls facilitate localization for females and bats. Female frogs prefer complex calls.

Question 4

Parasitoids

Answer 4

Blood-sucking flies. These flies are attracted to frog calling. Parasitoids often locate host by chemical signals : pheromones. In crickets, males that are most attractive to females also seem to be most vulnerable to parasitization.

Question 5

Balancing the risk of eavesdropping with the necessity to communicate

Answer 5

Change behavior (Can) - with bats present, frogs stopped calling. Graded response based on how close the bat was
Reduce detectability of signal (Rhys) - guppies have bright spots and blotches. Experiment was done and found that the guppies spots depended on if they were under selected pressure. Those with no pressure had spots evolved to oppose gravel size and stick out, those with pressure showed a decrease in spot number and brightness.
Signal in a different sensory modality (See) - Katydids spend less time calling where bats live. Instead they send vibratory signals through plants which are indetectable to bats.
Utilize a hidden or private channel of communication (U) - Dameselfish use UV signals to communicate. Main predators are insensitive to UV and UV scatters quickly so individuals must be close to observe it.