Neurons and HormonesBehavioral OrganizationSlide 3AromataseMechanisms for Organizing BehaviorNeural Command CenterSlide 7BlowflySlide 9Slide 10Biological ClockCricketsCircadian RhythmSlide 14MelatoninWhat happens if….Some Species Lack Circadian RhythmCircannual RhythmGolden Mantled Ground SquirrelGolden Mantled Ground Squirrel HibernationHow do Ground Squirrels Know When to Hibernate and Wake?What does the Data Tell Us?StonechatSeasonal TestesSlide 25PhotoperiodismEnvironment Influences Long Term CyclesLunar CyclesKangaroo RatsSlide 30Slide 31HormonesSlide 33Slide 34Testosterone Where Does it Come From?Leydig CellsTestosterone and ReproductionProduction Stimulated by BrainWhy Does Testosterone Effect Males and Females DifferentlySocial Environment Influences BehaviorSocial Interactions Prioritize BehaviorTestosterone Levels and AggressionTestosterone Levels and CompetitionJealousyExposure to TearsJapanese QuailHow Quail Get the Lovey FeelingTestosterone is ExpensiveTestosterone can Decrease Reproductive FitnessSlide Blotched Lizard3 color MorphsYellow Throated SneakerBlue Throated MonogomousOrange Throated DominantSlide 55Females Influenced By Social EnvironmentFemale Mice Prefer Dominant MalesDominant Males Alter BehaviorHow Does Male Time BehaviorInfanticideProgesterone & InfanticideProgesterone KnockoutSocial Influences on Circannual TimingSlide 64Slide 65Neurons and HormonesBehavioral Organization •Neurons and hormones allow multiple behaviors•Nervous systems are adapted to avoid conflicts between behaviorsBehavioral Organization •Male ring dove courtship–Aggressive chase, strutting–Nest soliciting•Male must perform both displays in order to convince female to mate•Interplay of hormonal cues–Testosterone–EstrogenAromatase•Converts testosterone into estrogenMechanisms for Organizing Behavior•Neural command centers•Clocks that schedule behaviors•Hormones that track physical and social environmentsNeural Command Center•Allows nervous system to prioritize behaviors•Command centers coordinate a specific behavior–Innate releasing mechanism–Central pattern generators•Multiple command centers communicate–Hierarchically organized–Can suppress conflicting activities•Ganglia are clusters of neurons outside of the brain–Ganglia in each segment controls each region•Brain is regulator that prevents conflicting behaviors–Inhibits ganglia from producing conflicting behaviorsBlowfly•Detect rotting food by olfaction and taste with their feet.–This promotes feeding•Have neural sensors in proboscis that senses sugar concentration.•If sugar concentration exceeds threshold, then feeding command center starts to fire and sucking begins.–Command center fires for 90 seconds, then feeding stops.–Repeat•Feeding command center is inhibited by stretch receptors in the foregut.•If the recurrent nerve is cut, feeding continues in 90 second intervals until gut ruptures.Mechanisms for Organizing Behavior•Neural command centers•Clocks that schedule behaviors•Hormones that track physical and social environmentsBiological Clock•Allows altering of behavioral prioritizing in response to changing environment•Biological clocks allows a timing mechanism for regulating behaviors•Example how do crickets know to only sing at night?–Are crickets responding to environmental conditions? Or using a biological clock?Crickets•If crickets are responding to environmental light levels, when light levels drop crickets will call•Crickets experimentally placed under 24 hr lights still called–Calling still begins approximately 25-26 hours after last calling sessionCircadian Rhythm•Environmental independent internal biological clock–24 hour cycles of behavioral change–Periods of activity and inactivity (often sleep)•Environmental cues like light/ dark can be used to adjust biological clockMelatonin•Hormone secreted by pineal gland in brain•Dark stimulates an increase in Melatonin production–Increased levels of Melatonin induce sleepiness•Melatonin production drops in dayWhat happens if….•http://www.youtube.com/watch?v=rGMTj45hW1o&NR=1•What are the challenges of living underground?•How do they detect seasons?Some Species Lack Circadian Rhythm•Naked Mole rat•Activity patterns from lab animals kept under constant low light•Dark bars indicate activity•http://www.youtube.com/watch?v=HydmFILYlzMCircannual Rhythm•Yearly cycles of behavior•Ultimate selection pressure –Winter, wet season, breeding season•Circannual rhythms are timed by a biological clock •Circannual rhythms may be modified by environmental cuesGolden Mantled Ground Squirrel•Coniferous forest–Cold high elevation winter conditions–Low ambient temperatures–Low food availability–Short active season•Hibernation to escape cold–Oct-May–Reduces metabolic costGolden Mantled Ground Squirrel Hibernation•Body temperature drops to approx 1 degree above ambient temperature•Heart and respiratory rates drop•Waste processing, gene expression, cell division suspended•Very little food eaten, survive on stored fat•Seasonal activities critical to survivalHow do Ground Squirrels Know When to Hibernate and Wake? •Does a biological clock regulate hibernation?•Lab ground squirrels were–Held at constant temperature??–Blinded??What does the Data Tell Us?•Ground squirrels hibernated yearly at appropriate timesStonechat•Kenya•Yearly wet season–Abundance of food resources (insects)•Reproductive seasonSeasonal Testes•Seasonal changes occur in testes size•Testes will increase in size–Maximize sperm and testosterone productionCircannual Rhythm•Stonechats brought to Germany•Maintained seasonal pattern with some alterationsPhotoperiodism•Response to seasonal changes in day length–Winter vs Spring??•Can trigger physiological, morphological and/ or behavioral changes•Important cue for tracking seasonal changesEnvironment Influences Long Term Cycles•Adjustment of circadian and circannual clocks allows behavior to adjust to environmental variation•Environment can influence behavior–Temperature, day length, moonlight, rainfall•Ex. Temperature can influence exact timing of emergence from hibernation –Allows adjustment for late or early winter–Timing is critical for food availabilityLunar Cycles•28 to 29 day cycle•Behaviors are influenced by phase of moonKangaroo Rats•Nocturnal desert rodents•Open habitat