Chapter 51 Behavioral Ecology Behavior actions or reactions is response to internal or external stimuli Nature vs Nurture Instinctive vs Deliberate Causes Subdivided Proximate HOW mechanism how the sensory neuron works Ultimate WHY what is the benefit of induction minimizing harm o Ex 2 Species of Lovebirds o Peach faced tuck and carry multiple bark strips at once in feathers o Fischer s carry single barks strip in beaks Hybrid birds tuck their bark into their feathers and then pull it back out Genetic drive to tuck but it is not complete with experience they have learned to not tuck but will not give up the impulse to turn around to try to tuck pre encoded into the genome Fixed Action Pattern o Ex Male Stickleback fish will attach anything that has red on their belly side o Ex Newborn will grasp anything that touches your hand reflex Acquisition of Knowledge gaining a skill and experiencing it Humans are programmed to learn language open to learning rhythms and sounds of whatever language we are exposed to early in life Which language we learn depends on our exposure The Scientists in the Crib Alison Genic et al 1999 Publisher Perennial Core questions of Behavior Ecology What should I eat Who should I mate with Where should I live How should I communicate When should I cooperate 1 Foraging Behaviors animals 2 Mating Systems Parental Investment Fish on seaward reef slope are often zooplankton feeders Zooplankton made up category of many small organisms Protists bacteria small o Level of Parental Investment correlates to courtship and mating behaviors There are many exceptions to the female chooses pattern Male seahorses care for the young after female hands over eggs Male Betas Chinese fighting fish build bubble nests and protect fertilized eggs Promiscuous no strong pair bonds Typical of fish Coral reef fish often change sex during life Or are hermaphrodites gives species and edge in times of predication Sex in Open Water 1 Broadcast Spawning a Subtype Pair Spawning 2 Underwater Nests 3 Brooding Banded Pipefish a Male banded pipefish male cardinalfish mouth brooding Sex on the Reef o Many coral fish change sex during life o Others are hermaphrodites but can produce only one gamete types at a time o Coral Spawning coordinated by tides temperature light 3 Home Sweet Home Kinesis activity level change in response to stimulus and Taxis directional response Landmark Usage Digger wasp Honey bees Compass electromagnetic field detection Migration regular movement over long distances Ants use number of steps to measure distance travelled How Do I Get Home Spiny Lobster Tail o Magnetic Fields and Latitude Liens o Do they orient to magnetic field Yes they do but could be using different ways of doing it from their capture site vs transport site o Transport with and without magnets lobsters are not remembering where home is it is still magnetic fields o Can we mimic in the lab Put the lobsters in a magnetic field and they are still able to read and navigate back to their capture sites 4 Communication Social signal response communication o Ex Waggle Dance in honeybees direction of waggle indicates the direction from the sun o Honeybee the round dance is just an abbreviated waggle dance They are the same both communicate distance and direction 1 Ritualized Competitions 2 Courtship Rituals 3 Pheromones 4 Transfer of external information honeybees communicate where to forage 5 Defense of Territory Deception happens o Ex Female Photuris fireflies flash Anglerfish uses a lure to attract prey 5 Competition and Cooperation Examples of Competitive Behavior 1 Agonistic Behavior threatening and submissive behavior Often ritualized In stable social situations also involves reconciliation behavior a Benefit rank determined with minimal risk 2 Dominance Hierarchies related to agnostic behavior Know your place a Benefit top animal gets primary access to resources Lower ranked animals minimize risks of moral combat 3 Territoriality area defend by an individual or a group against others of same species Ownership maintained through agonistic behavior Examples of cooperative and altruistic behavior o Cooperation usually benefits all parties wolf packs hunt as a group o Altruism self sacrifice bee societies workers are sterile work for queen Doesn t haven an obvious benefit o Inclusive Fitness the relative number of an individuals alleles that are passed on from generation to generation either as the result of his or her won reproductive success OR that of related individuals o Self sacrifice for a relative ensures some of your genes are likely to be passed on o Coefficient of relatedness o Hamilton s Rule for natural selection to favor altruism the benefit to the recipient multiplied by the relatedness to the recipient must outweigh the cost to the altruist o Kin Selection selection favoring relatives Ex Leafcutter ants the first agriculture Leaf cutter ants and foraging behavior or courseweb Leaves are not directly consumed Used to farm a fungus that the ants eat Strong correlation between size and transporting ant and cut leaf size However larger pieces cut when distance must carry is greater smaller pieces when food deprived or using unfamiliar leaves Young ants do the cutting older ones carry Young ants have sharper jaws do most of the cutting As age increases jaws become more dull switch to carrying role Question Do ants make a size and or shape adjustment when the trail between source and nest is contrained Nest Tray Food tray with leaves Bridge between the two trays 30cm long 5cm wide Experimental bridges 24h acclimation o New uncovered control o New covered 1cm clearance 10cm long 5 cm from end Synthetic Food Actual leaves to stimulate foraging Parafilm soaked in crushed leaf solution Some key factors measured With and without bridge cover o Bridge traffic o Travel duration o Size of ants doing the carrying o Size of load shape of load o Interaction rate between outgoing empty and incoming laden ants on bridge Findings Traffic volume number of ants crossing bridge unaffected Number of laden ants much greater with covered bridge Time to cross Strongly affected for ants carrying a load o Why Friction with cover Different carrying posture required Small but significant difference of size of ants carrying loads Laden ants tended to be bigger on both bridges Laden ants on covered bridge were larger than laden ants on uncovered bridge The hard the work the bigger the ant Individuals cut smaller leaves
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