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Behavior Development b. Learning. Learning is a change in an animal’s behavior linked to a particular experience it has Brain properties change by gene and environmental interactions . Learning. Forms of learning Imprinting Specialized learning Variation in learning behavior
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Learning • Learning is a change in an animal’s behavior linked to a particular experience it has • Brain properties change by gene and environmental interactions
Learning • Forms of learning • Imprinting • Specialized learning • Variation in learning behavior • Environmental influences
Imprinting • http://www.youtube.com/watch?v=7OynlzqtxmY • Why would this behavior be adaptive?
Imprinting • Occurs when a young animal’s early social interactions lead to learning • Functions • Recognition of parents in animals with preccocial young (ex geese) • Recognition of an appropriate sexual partner • Dependence of recognition on recognition • Young animal must see model to recognize it • Learning is flexible- model does not need to look like parent or even same species
Konrad Lorenz • Imprinting in Greylag Geese • Imprint on humans • Later preferred Humans as mates • http://www.youtube.com/watch?v=2UIU9XH-mUI • http://www.youtube.com/watch?v=SK65euK1FGU
Great Tits & Blue Tits Imprinting has different effects among species
Imprinting has Different Effects Among Species • When cross imprinted • Some individuals became imprinted on opposite species • None of the Great Tits mated with a member of it’s own species • Formed a mate preference based on imprinted foster parent • Most of Blue Tits mated within it’s own species • Exhibited a different developmental interaction
Specialized Learning • Memory formation to aid in finding food
Clark’s Nutcracker • Whack cones of Whitebark pine • Also eats limber pine seeds • Seed pouch under tongue • Distribute seeds in Caches • Cache more than they will retrieve • Hides up to 38,000 of seeds per season • Up to 5,000 separate caches • Up to 20 miles away • Buries seeds in fall downslope • In winter will retrieve
Clark’s Nutcracker • Nutcrackers able to relocate caches with up to 80% accuracy • Recall memory for months • Use landmarks to relocate caches
Seeds germinate in clusters Un-retrieved caches create new stands
Learning varies among members of the same species • Chickadees in Alaska require fewer inspections to locate food stores that the same species in Colorado • What causes variation among individuals?
Factors that Influence the Development of Learned Behavior • Environmental • Genetic
Environmental Differences • Individuals can learn based on their interactions as young • Interactions with siblings can shape behavior • Kin recognition • Used to identify closely related individuals from potential rivals • Cues such as olfaction & sight can be used as recognition cues
Polistes Paper Wasps • Paper wasps use both olfactory cues to recognize individuals from the same nest • Females are also able to recognize facial markings • Individuals with altered face markings were attacked more frequently
Belding’s Ground Squirrels • Lives in subalpine and alpine communities • Meadows • Social ground squirrel • Females remain, males disperse • Closely related females help raise and protect each others offspring • Prey species lifestyle • Aerial predators such as hawks • Ground predators such as weasels • Colonial living aids in protection
Kin Recognition • Kin recognition critical • Helps identify closely related for assistance • Ability to recognize intruders • Prevents inbreeding • Strong selection pressure favoring genes that code for recognition behaviors
Kin Recognition • Signals used to identify kin include • Scent • Appearance
Ground Squirrel Musical Chairs • Newborn Ground squirrels were moved from their nests into 4 groups • Siblings reared apart • Siblings reared together • Non-siblings raised apart • Non-siblings raised together
Belding’s Ground Squirrel Torture! • After raised in their respective groups ground squirrels were placed in an arena to test their ability to recognize each other • Recognition was measure using levels of aggression • Aggression indicates less kin recognition
What would you predict? • Siblings reared apart • Siblings reared together • Non-siblings raised apart • Non-siblings raised together
Individuals learn based on their olfactory interactions as young • Ground squirrels raised together learned each others smell and were less aggressive towards each other • Independent of whether they were siblings • Ground squirrels raised separately tended to be more aggressive toward each other
Have we met? • Biological sisters raised apart had fewer aggressive interactions than nonsiblings raised apart • Indicates siblings have a secondary learned behavior for recognizing kin
Why are Females more Discriminating in their Sense of Smell?
Armpit Effect • Animals have ability to recognize relatives they have never met before • Individuals can learn their own olfactory profile • Self recognition provides a reference to compare other individual’s smells to • Individuals who smell similar are more closely related, whereas individuals that smell less similar are less closely related
Chemical Communication • Oral and dorsal glands • Nasal investigation • Scent mark behavior • 5 odors that are individually distinct
Scent Discrimination • Individuals learn to recognize their own scent • Spend more time sniffing less closely related relatives
Ultimate Causation • Kin Recognition by using scent discrimination allows Belding’s ground squirrels in order to • Helps identify closely related for assistance • Ability to recognize intruders • Prevents inbreeding
Genetic Differences • Some behavioral phenotypes can be determined by a genetic component • Alleles that code for behavioral differences can be selected for or against by natural selection to maximize fitness
Western Terrestrial Garter SnakeThamnophis elegans • Highly variable in habitat • Can be found near water or away from water • Feeds on a wide array of food sources • Slugs, worms, leeches, tadpoles, frogs, fish, insects, lizards, small birds
Western Terrestrial Garter Snake Populations • Coastal and inland snake populations exhibit variation in their diet preference • Inland population • Lives in arid habitats near lakes and streams • Feed primarily on fish and frogs • Coastal populations • Lives in moist coast ranges • Feed primarily on banana slugs Is variation in prey preference genetic?
Garter Snake Prey Preference Experiment • Pregnant snakes from both coastal and inland populations were brought into lab • Immediately after birth offspring were isolated • Controlling for environmental learning influences • After several days each snake offspring was offered a segment of Banana slug • http://www.youtube.com/watch?v=92InYz1cU2o
Garter Snake populations exhibit Prey Preference • Feeding score indicates how many days a snake ate the offered slug • A score of 10 indicates slug was eaten every offering • Coastal slugs exhibited greater likelihood of eating slug than inland garter
What happens if Garter snakes are offered multiple prey options?
The Tadpole vs Slug Taste Test • Newborn garter snakes are offered cotton swabs with different prey “juice” • Snakes were offered swab for 1 minute • Preference was measured by number of tongue flicks What?
Tongue Flicking in Snakes • Tongue flicking is a sensory-gathering behavior • Olfaction • Tongue flicks are used during prey trailing, foraging, mate searching • Chemical molecules gathered by the tongue are delivered to the Vomeronasal organ on roof of mouth
Tongue Flicking in Snakes • Ability to triangulate chemical cues in the environment is maximized by: • Waving tongue in the air to detect vertical gradients • Forked tongue increases sensitivity to chemical gradients in the environment • Tongue flicking rate http://vimeo.com/1206868
Vomeronasal Organ • AKA Jacobsen’s organ http://www.youtube.com/watch?v=yzC8DZK0aT4
The Tadpole vs Slug Taste Test • There was no difference in preference to toad tadpole samples • i.e. Both populations had about the same number of tongue flicks to the tadpole covered cotton swab • Coastal garter snakes showed higher preference to slug samples • i.e. Coastal population had a significantly higher number of tongue flicks to the slug covered cotton swab • Genetic crosses of both populations indicated that this prey preference was being driven by a variation in alleles
How Could Prey Preference Variation Occurred? • Remember the bell shaped curve? • A rare slug feeding allele could have become more prevalent in the coastal population • Hypothesis- Garter snakes with rare slug eating allele were able to gain a fitness advantage because they could acquire more energy from eating a slug than a snake eating a tadpole Selection Pressure