Animal Behavior

Behavior = causes/consequences of the nervous system

  • Behavioral ecology → study of ecological and evolutionary basis for animal behavior

  • maintain homeostasis, bad behavior→ don’t pass on your genes

  • physiology shapes behavior→ feeds back and shapes physiology→ behavior can evolve, under natural selection

Kleptoparasite = harass others for food and steal it

Body shape, color, etc influence mating and recognition

How behaviors occur and why they arise

4 Major Questions- proximate and ultimate

  1. How do behaviors occur?

    1. stimulus

    2. mechanism

  2. How does experience influence behavior?

  1. Why is a behavior adaptive? Does it aid survival and reproduction?

Fixed Action Pattern- directly linked to stimulus

  • an unlearned behavior in response to a sign stimulus (External cue)

  • once behavior begins, continues until completed

  • ex: male sticklebacks attack any red stimulus b/c other males have red undersides, very territorial, don’t attack female sticklebacks b/c not red

  • Human Impacts:

    • Australian jewel beetle stimulus = orange and bumpy b/c males think they’ve found a mate, when beer bottles thrown out, orange and bumpy→ seem huge and attractive→ overheat and do not reproduce

  • behavioral traits that may have been adaptive become maladaptive in new environments

Learning establishes links b/w Experience and Behavior

  • Imprinting- has a sensitive period (critical period) when specific behaviors are learned

    • if critical period is missed→ some behaviors may never be learned

    • can be used successfully in conservation efforts when it comes to migratory bird species

    • can also go wrong if imprinted on wrong species→ hard to find mates later especially when imprinted on humans and released back into the wild

  • Spatial Learning and Cognitive Maps

    • many animals can build an understanding of the environment they’re in→ create a cognitive map

  • Associative Learning- ability to associate one feature with another

    • Classical Conditioning- stimulus becomes associated with an outcome

    • Operant Conditioning- behavior associated with a reward or a punishment

  • Depends on nervous system development and organization

    • Pigeons associate danger with sound, not color, but associate food with color

    • rats associate sickness with smell→ limited by biology, but also makes sort of sense why these associations would come about.

  • Cognition involves awareness, reasoning, recollection, and judgement

    • Problem-solving→ cognitive activity of devising a method to proceed from one condition to another in the face of real/apparent obstacles

    • apply abstract rules to novel stimuli→ goes past simple conditioning

  • Social Learning- observing and interpreting the behaviors/consequences of others

    • Culture- system of info transfer through social learning/teaching that influences the behavior of individuals in a population

      • can alter behavioral phenotype→ influence fitness

      • much faster than evolution

Movement

  • Kinesis = movement but not in a specific direction, change speed or how often it turns while moving

    • Ex: Sow bugs move around randomly until they find a moist spot

  • Taxis= recognize a stimulus and move either toward or away it

    • Ex: Moths fly towards a light source, bacteria move towards nutrients up through a chemical gradient

  • Migration = regular, long-distance movement, typically seasonal

    • Ex: sea turtle migration, magnetism but also some animals have multiple systems like using the sun, circadian clocks, use stars

Behavioral Rhythms

  • Circadian rhythms

    • rest and activity cycles regulated by circadian clock

    • light and dark cycles but light does not create the rhythm, resets and realigns it

    • circannual rhythm daylight and darkness = common seasonal cues

  • Lunar cycles

    • tide movements can also influence behaviors

Signals and Communication

  • Signal = stimulus generated by one animal guiding the behavior of another

    • not accidentally, shaped by natural selection for communication

  • Communication = transmission and reception of signals b/w animals

Selection

  • Food

    • Foraging = food obtaining behaviors

    • optimal foraging model→ animals compromise b/w benefits of nutrition and cost of obtaining food

    • natural selection should favor strategies that minimize cost and maximize benefits

  • Reproduction

    • Interactions b/w mating systems and behaviors

    • Monogamous pairs often are similar in appearance and have intricate courtship displays involving both partners

    • Polygamous pairs→ exhibit choosiness

      • Polygynous→ sperm producers have a flashier display and compete with each other

      • Polyandrous→ egg producers compete w/ flashy displays

    • Parental Care- any investment in offspring after the production of gametes

      • trade off b/w the number of offspring and time commitment

        • most turtles invest in numbers, most birds invest in parental care

      • Parental certainty often linked to differences in parental care→ lower parental certainty = lower parental care

        • mate-guarding against other males

        • removal of previous males’ sperm

        • sperm competition- try to produce more sperm to out compete others

        • genital plug

Game Theory - evaluates strategies where the outcome depends on the strategies of all players, like the prisoner’s dilemma

  • Negative freq dependent selection→ fitness of a phenotype declines when it is too common→ depends on how common the strategy used is

    • preserves genetic variation in a population

    • phenotype frequency oscillates b/c the uncommon phenotype has the advantage

    • outcome of game theory

  • Lizard Case Study

    • blue = somewhat aggressive, defend smaller territories, places w/ smaller egg producers (lose to orange)

    • orange = very aggressive, larger territories, many egg producers (lose to yellow)

    • yellow = nonterritorial, sneakier lizards (lose to blue)

    • each color kept in check by other colors, females bring declining frequencies back b/c prefer rarer phenotypes→ negative frequency dependent selection

    • also altruism b/c blue males warn other males that yellows+predators are around

  • Altruism = behavior that reduces an animal’s individual fitness but increases the fitness of other individuals in the population

    • like animals giving warning calls or honeybees stinging intruders→ draws attention to themselves but allow for others to get to safety

    • helps relatives pass on shared genes

    • inclusive fitness- total effect an individual has on proliferating its genes by producing offspring and providing aid that enables other close retalitves to produce offspring

      • relatedness = probability of shared genes

    • Kin selection- quantify the effect of altruism on fitness

    • Hamilton’s rule→ coefficient of relatedness times benefit of recipient must be greater than cost to altruist for altruism to be favored

Gene x Environment interactions

  • Garter snakes eat different diets based on whether they are coastal or inland (eat vs not banana slugs)

    • why? environmental or genetic difference?

    • banana slugs common on coast

    • snakes collected and hatched in lab, coastal still ate slugs and inland did not→ likely genetic, sensory differences

    • coastal snakes found an abundant resource in banana slugs→ more food→ higher fitness→ learned to eat them

  • Courtship in fruit flies

    • response to multiple stimuli

    • specific genetic control of behavior

    • single gene (fru) controls courtship behavior

      • courtship performed by sperm producer

      • no gene→ no courting→ no mating

      • when egg producers are given this gene, they start courtship displays

  • Pair bonds in voles

    • prairie voles monogamous, ADH released

    • meadow voles polygynous, ADH suppressed