Behavioral Ecology - Communication

What is the difference between senders and receivers?

Sender: Individual who provides information (intentionally or unintentionally)

Receiver: Individual who detects information

What is the difference between cues and signals?

Cue: Produced as a byproduct of other behavior; isn’t shaped by natural selection to convey information from the sender. Ex: A bear emits CO₂ as a byproduct of respiration

Signal: Shaped by natural selection to convey information from sender to receiver, and thereby influence receiver’s behavior

What are two example of cues?

1) A bear (sender) emits CO₂ as a byproduct of respiration. Mosquitoes (receiver) then use the CO₂ as a cue for where to find a bloodmeal
2) A mouse (sender) makes rustling sounds in undergrowth while foraging. An owl (receiver) then uses the sounds made to find prey

What are two example of signals?

1) A baby (sender) cries in order to get food, where a parent (receiver) modifies their behavior by feeding the baby to ensure their baby remains healthy
2) Male bowerbirds (sender) make bowers to attract females mates, where female bowerbirds (receiver) are able pay attention to bowers in order to get information about the quality of males and select the best male

What the three ways in which signal honesty is maintained?

1) Indices
2) Handicaps
3) Common interest

What are indices?

Signals whose intensity is causally related to the quality being signaled; signals that can’t be faked

What are two examples of indices?

1) In peacocks, the size of the tail is constrained by body size of male. More spots are associated with bigger tails

2) In red deer, the roars emitted by males provide information about the size and physical condition of the male before combat. Deeper roars are associated with larger deer

What are handicaps?

A signal that’s costly for a low-quality individual to maintain; not necessarily linked to trait being signaled

What are two examples of handicaps?

1) In red deer, antlers are heavy to carry around; only the most high-quality are capable of bearing their weight
2) In peacocks, tails are often heavy and unwieldy; only high quality males are capable of dealing with their drawbacks

What is common interest?

When the sender and receiver have a common interest, there’s no benefit to deceiving the receiver

What are three examples of common interest?

1) Belding’s ground squirrels performing alarm calls when a predator is nearby to protect related kin
2) Honeybee waggle dances, which are used for communicating about sources or new colony sites

3) Female fruit fly extruding her ovipositor to signal to a male fruit fly harasser she has already mated. Female doesn’t get harassed and the male doesn’t waste time/energy

What are dishonest signals?

Signals that deceive the receiver

What are two examples of dishonest signaling?

1) Batesian mimicry: A predator avoids eating a poisonous prey; occasionally avoids eating prey that’s actually not poisonous
2) Anglerfish: A small fish finds food, low number of small fish in population mistake anglerfish for food and get eaten