Behavioral Ecology

MOSTLY VOCAB – listen to concepts/stories to explain each

term

Behavioral ecologyThe study of how animal behavior develops, evolves, and contributes to survival and reproductive success

Ethology - a narrower field that just studies behavior, without all the ecological parts

We ask 2 kinds of questions

1. Proximate questions - ask about the environmental stimuli that trigger a behavior (“how” questions)

e.g. “How does the length of daylight affect breeding behavior in cranes?”

2. Ultimate questions - ask about the evolutionary significance of a behavior (“why” questions)

e.g. “Why did natural selection favor this behavior and not a different one?”

Animal Behaviors1. Fixed Action

Patterns (FAP)Unlearned behaviorsUsually unchangeableInnate (genetic, born able to do it)Triggered by an external stimulusCarried to completion once initiated

Story of the sticklebacks

Animal Behaviors2. Imprinting

Includes both learning and innate componentsUsually irreversibleComes about during a sensitive period during development when the behavior MUST be learned

The story of ducks, geese, cranes

Caution

All behaviors have some genetic and some environmental componentThe question is not “Nature or Nurture”The question is “How do both nature and nurture affect behavior?”

Animal Behaviors w/ strong genetic basis

Kinesis A change in activity in response to a stimulus; a change in speed – move faster in unfavorable environments and slower in favorable ones. The net result is more time in favorable placesNot directed

The story of the isopods

Animal Behaviors w/ strong genetic basis

TaxisAn automatic, reflex oriented movement toward (positive taxis) or away from (negative taxis) something, like moths to the light

The story of the fish

Animal Behaviors w/ strong genetic basis Migration

Strong genetic component

Story of the black caps

Some populations migrate; some do notIn migrating populations, caged birds show restlessness during migration time

Animal Communication is strongly genetic

Use visual, auditory, chemical, tactile, and electrical signals to communicate

Pheromones - chemical signal that affects behaviorBird songs are at least partly learnedInsect songs are almost purely genetic

Animal Behaviors w/ a strong environmental basis

Environmental factors like:Quality of dietSocial interactionsLearning opportunities

A coyote with a face full of porcupine quills - ouch!

Animal behaviors with a strong environmental basisLearning - the modification of behavior based on specific experiences

ImprintingHabituationSpatial learningCognitive mapsAssociative learningCognition and

problem solving Chimps teaching each other how to hammer open palm nuts

HabituationLoss of responsiveness to stimuli

Venus flytrap closes when triggered, unless it keeps getting touched without the reward of foodBaby ducks run for cover when something flies overhead, unless it keeps happening and no one gets attackedResearchers often have to habituate their study population to their presence

Spatial Learning

The modification of behavior based on experience with the spatial structure of the environment

Where the good nesting sites are, where food can be found, what areas to avoid Wasps use landmarks to

locate nests

Cognitive Maps

An internal representation of the spatial relationships in an animal’s environment

Ravens and jays store food in cachesMay store 1000s of nuts in 1000s of different placesThey can remember where food is stored and even what kind of food is stored in each place using landmarks as identifiers

Associative learningThe ability to associate one feature of the environment with another

Classical conditioning - an arbitrary stimulus is associated with reward or punishment - Pavlov’s dogsOperant conditioning - an animal learns to associate its own behavior with reward or punishment

Cognition & problem solvingThe ability of an animal to perceive and process information

Some animals have very advanced problem solving skills

PrimatesDolphinsMany birds like crows, ravens, and jaysOctopi

Animals can learn from each other

Natural selection can result in the evolution of behaviors

Best evidence for this is variations in behaviors between and within species

Example:Different populations of garter snakes prey on different animals

Natural selection favors individuals who can capitalize on the dominant food source

Optimal Foraging TheoryForaging is a compromise between the benefits of getting food and the energy spent getting it or the risk of getting eaten by a predator while trying to get foodNatural selection favors those that maximize the benefits and minimize the costs

Optimal height drop is 5 m - least amount of work for most benefit…most birds drop frfom exactly this height

Mating BehaviorsMay be

Promiscuous - no lasting relationshipsMonogomous - 1 male w/ 1 female

Both sexes often look alikeMany birds are this way because the young require so much care they need 2 parents

Polygymous - one individual mating w/ several others

Polygyny - 1 male, several females - more common

Female mammals care for young by nursing - don’t need dad to help so he maximizes his reproductive success by mating with severalMales often “prettier” in this type

Polyandry - 1 female, several males

Mating BehaviorsCertainty of paternity an issue

Of course the kids are the mom’s, but are they the dad’s?With internal fertilization, behaviors like guarding females or releasing large amounts of sperm occur to help ensure paternityWith external fertilization, paternity is pretty much a given, so males may help with care of the young more

Male jawfish cares for young…external fertilization guarantees they are his

Bull male protects his harem of females from other males

Mating BehaviorsFemale choice has led to the natural selection of particular traits in males

Social Behavior & Altruism

Altruism - selfless behavior for the benefit of othersBenefits the passing of genes - which is what “success” is all about in biology

One queen is cared for by all others…they even die to save her

Altruism and relatedness

Coefficient of relatedness – a statistic that represents the average number of genes 2 individuals shareThe more they share, the more likely they will help each otherSiblings share 50% of their genes

Agnostic Behavior

Conflict behavior over a resource; usually just big displays of strength

Dominance Hierarchies

Ranking among members of a group; subject to change; reduces conflict among members since everyone knows their place

Territoriality

Defense of territory to keep others out