ECOL 182R 1st Edition Lecture 4 Outline of Last Lecture I Adaptive behavior A Four F s of Behavior B Sexual and asexual II Why is sex so common A Inbreeding III Male female differences A Patterns B Sperm egg IV Animal reproductive behavior A Choosing mates V Plant reproductive behavior A Choosing mates Outline of Current Lecture I Levels of Analysis A Mechanism B Development C Function D Evolution II Altruism A Manipulation B Reciprocity C Kin Selection Hamilton s Rule III Instincts Current Lecture Why do lizards do pushups beatles stand on their heads or ants follow a trail Why do male birds have extravagant plumage and courtship displays In S Arizona walnut fly males defend fruit and mate with females as they arrive They re territorial on the fruit and patrol the fruit They box pretty literally any intruders Why What sensory stimuli because males to box Has to do with mechanism Do they box better with age experience Has to do with development Does winning a contest benefit males Has to do with function Did ancestors of walnut flies box Has to do with evolution They re called Levels of Analysis Mechanism the physiological or neurological basis of a behavior How does it work how is this behavior produced Analysis of mechanisms might address sensory organs and receptors brains nerves and neurons hormones Ex Sea turtles use the Earth s magnetic field to navigate in ocean This mechanism is called magnetoreception Development the role of age and experience in behavior Also called ontogeny How does it develop how do age and experience influence a behavior Analysis of development may address learning habituation imprinting and role of social environment Ex Nest finding my beewolves wasps They make a burrow then cover it up and fly to find a bee to paralyze Uncover nest put bee inside and lay an egg on it Offspring develop on the bee But how did they find their nests again when they flew away and had covered it They do a few circles in flight around in before they fly to find the bee Hypothesis When they leave the nest they memorize local landmarks so they learn to recognize the spot Experiments to figure that out 1 Mixed up local landmarks 2 Created set of landmarks then moved them to surround a spot a meter away Function the adaptive function of a behavior Why has natural selection favored this behavior how does the behavior influence fitness of the organism Ex Squirrels like to flick tails Temperature of tali varies with nature of threat Got really hot when presented with a rattle snake but temperature stayed the same when presented with a gopher snake Rattlesnakes can detect infrared using pit organs A robot squirrel was made and when he started shaking his hot tail rattlesnake changed his behavior from predatory to defensive Hypotheses 1 Squirrel with hot tail looks bigger Adult ones that can bite rattlesnakes and aren t the target for rattlesnakes They favor defenseless pups 2 Tail signal informs rattlesnake that squirrel has detected it Evolution What is the evolutionary history of the behavior Where did the behavior come from in the evolution of this group The analysis of evolution might map the behavior into an existing phylogeny Swiftlet birds Evolution of echolocation in cave swiftlets mapped into a phylogeny What does it tell us Altruism any behavior that benefits a recipient while incurring a cost to its donor Ex alarm calls in ground squirrels helping behavior in birds mammals sterile castes in honey bees ants naked mole rats There are 3 main explanations for altruism 1 Manipulation the donor is a dupe In other words altruism through ignorance Ex Brood parasitism Cowbirds and cuckoos lay eggs in nests of host birds Host bird raises parasite young Why do they remove a host egg or two before laying their own because maybe the mama bird can count Need to make sure the mama bird can t tell that one of their eggs is not actually theirs Parasite species have broken the code by which young are recognized by a mother bird Code involves features of egg and gaping response of baby birds And why does the cuckoo hatchling throw the other eggs out For room to grow Host keeps feeding its monstrous child 2 Reciprocity you scratch my back I ll scratch yours Takes the altruism out of altruism It is cooperation In olive baboons males form an alliance to wrest females from current mates Cotton top tamarins give food preferentially to those who give to them SO 1 Train actor tamarin to always pull food toward companion cooperator 2 Train another actor to never pull food toward companion defector 3 Pair test monkey with one of above types 4 Test monkey later given opportunity to pull food towards one of other companion The test monkey pulled food more if they had experienced cooperation that if they had experienced unhelpfulness Very common in humans We exercise indirect reciprocity Reciprocity in which the return for a donor s act comes forms someone other than the recipient I ll scratch your back if someone else scratches mine 3 Kin Selection Propagating your genes by helping genetic relatives propagate their genes Ex Ground squirrels produce an alarm call to warn colony of predator Hamilton s Rule conditions for altruism towards genetic relatives rb c 1 b benefits to recipient c cost to donor r coefficient of relatedness The more related the more likely to call out the alarm The behavior evolves when the cost to the donor is offset by benefit to the relative a more distant relative required greater benefit Sterile castes in naked mole rats live underground and feed on plant roots Are highly inbred leading to high genetic relatedness Breeding restricted to a single queen Sterile casts perform different jobs including defense What makes this altruism There are some working for colony that aren t getting anything out of it What makes this kin selection They re highly genetically related lots of inbreeding What are the relative costs and benefits of learning an instinct Instincts are beneficial when mistakes are not an option Ex hesitating instinctively at the edge of a cliff The cost is that instinctive behavior is inflexible Sometimes exploited by enemies Ex codebreaking in brood parasites Benefits of learning Flexibility different lessons in different environments Costs Learning involves mistakes Requires energy and brain resources