Communication and Signaling

What makes a signal worth believing? Why don't animals just lie all the time?

To be social animals must be able to … individuals and … with them including solitary animals for mating

Recognize, Communicate

When an animal meets another what three questions does it ask

Is it mine (species) , which one is it (individual), is it related to me (kin)

Coots learn which chicks are theirs

Other birds often dump eggs into coot nest, the graph shows that coots use recognition rules to know which chicks are theirs, learn the first hatched chicks and stick with them has highest fitness

4 channels of communication + examples

Visual (squid change color) , auditory (pika calls), chemical (lynx scent marks), mechanical (mosquito wingbeat)

Signal

Sender INTENDS to send it evolving for communication (cat hissing and arching back)

Cue

Sender did NOT intend to send it but the receiver uses it anyways (moth wingbeat heard by a bat or footprint in mud)

Case Study: The Plainfin Midshipman

Type I males: Grow large, build nest, defends territories

Type II males: sneakers looking like females and dart to fertilize eggs in type I

What is the signal from Plainfin Midshipman case study

Females make a grunt sound and sneaker males copy the sound to trick big male into thinking a female is in his nest

If a sneaker copies a female grunt, who is the signal for, and who is fooled?

The signal is for the big male and the big male is fooled

How is the hum made

fish uses swim bladder as a drum, two specialized muscles rapidly beat drum causing it to vibrate, vocal pattern generator in brain sets rhythm and pace of muscle contractions hormonal switch turns the hum on during the spring

Apply Plainfin Midshipman case study to Tinbergen's four questions

1. Mechanism: Bladder + muscles + hormones start grunt

2. Development: Fork development where males to be type I or II

3. Function: Hum attracts females mates, allows males to steal mates

4. Evolutionary: Evolved in dark water where sound can travel

Boat Noise and Plainfin Midshipman significance + what it is

When boats are around the red dots are lower than blue meaning when boats are around fish hum way less lowering their reproductive success, but in the graph growl drops a little so if big male stop humming sneakers might take advantage of it

Territory

Defended area that may hold food, water, shelter, nest, mates

Resource holding potential

An animal’s physical ability to win a fight. Signaling RHP early means loser gives up without a fight saving both animals’ energy + time

Gause's Law

If two species compete for the same resource one either goes extinct or shifts to a new niche

Honest Signals

A body feature, behavior or chemical that shows an animal’s ability to win—Signals you can’t fake because they cost too much (deep frog call requires massive body that a tiny frog can’t achieve)

Examples of honest signaling

color, size, call, scent strength

Why wouldn’t a loser just fake it?

Losers can’t fake because it would be too costly to do so

The Tail Flare Graph

A lizard flares its tail more when it wins a fight (possibly honest signal)

Dear enemy effect

Animals fight familiar neighbors LESS than they fight strangers because neighbors already know who owns what and don’t waste energy fighting

What’s important about the dear enemy effect

Knowing your neighbors saves energy

Howler Monkeys

In a study they played calls of neighbors on usual side, misplaced neighbors, and strangers–Males answered strangers and rule-breaking neighbors, not good neighbors.

Why do territory owners (holders) usually win fights?

They have more to lose. If an intruder loses he just goes somewhere else if the owner loses he loses his home and mates

Payoff asymmetry

Holding a territory usually pays more than taking one so owner has more to lose than intruder

How was holding a territory tested?

Removing an owner from his area for a while and found the longer he was gone the less likely he’d get it back because “intruder” moves in and becomes “new owner”

Aposematic coloration

Bright, bold colors and patterns that send a signal of (toxic or foul tasting) receiver is predator

Müllerian mimicry

Two toxic species copy each other (honest signaling because everyone is toxic)

Batesian Mimicry

Harmless species copies toxic and only works if the real toxic species is common

In the Yellowthroat and Cowbird example, which kin recognition rule is the parent using, and why is she fooled?

Place rule that whoever is in her nest is kin and is fooled because the Cowbird is a brood parasite that tricked parent into feeding proving that kin recognition rules are only simple shortcuts that can be exploited