Zoology 425 1st Edition Exam 2 Study Guide Lec 1 2 17 15 sleep exposure index measure vulnerability while sleeping o negatively related to percent of time that the organism spends in REM sleep harder to wake from predator prey interactions shape what prey behavior occurs flight initiation distance o lots of things affect whether or not prey decide to flee 1 distance to refuge modified by time of day how much cover there is prey pay attention to environment 2 prey experience predator density sequential predator approaches 3 predatory effects predator speed and size directness of attack o other means of defense may be relied upon foraging anti predator behavior cost of risk o Joel Brown use animal foraging behavior to ask prey about anti prey behavior o giving up density GUD P C MOC density of a resource when a forager gives up and leaves patch describes what s left in the patch when the forager leaves every time something is removed less remains in substrate generates diminishing returns marginal value problem terms P predation risk can bump a gain curve if it s made riskier low predation risk longer time spent in patch lower cost tangent lines are parallel to average slope quality includes risk high quality can have same yield as low patch but has lower risk which is what inc its quality high risk environment can lead to higher rate of see yield energetic cost of predation risk difference between two patches harvesting perspective same seed quantity risk perspective different risk different quality high risk patch will have more seeds remaining than safe patch C cost metabolic MOC missed opportunity costs catch all for what s missing bc of what you chose to do with your time stay longer in safe environment leave sooner in high risk environment design a study where trays are paired assume C and MOC in both are equal values cons different thermal costs actually confounds focus on predation risk present in same environment risk allocation hypothesis if you hide long enough probability of starving probability of being eaten o may be many situations where animals are willing to trade a gain at cost of predator risk o at some point you stop worrying about predators and start worrying about starving o short term studies don t represent long term reality direct vs indirect cues o information in environment to optimize activities in risky world information is some state in the environment that can be used by the organism to predict events info reduces ambiguity regarding a particular outcome cue some component of environment that can be perceived and provides o o information direct cues cues produced by predator or by act of predation ex sight of predator sound produced by predator chemical smell macerated conspecifics urine feces indirect cues associated with risk but not produced by predator ex habitat is there a refuge lighting conditions weather o can evaluate anti predator behavior by providing cues o aphids use direct cues to initiate anti predator behavior o chemosensory assessment of predation risk information is used by about every organism o measuring distance to a refuge is usually testing indirect cues o rodent foraging does not change with direct cues did pay attention to indirect cues suggests that indirect cues are more important rain allowed them to be harder to detect visually and acoustically rodents get killed by everything need to prioritize risk indirect cues provide info about overall risk applicable to all predators island wide predator manipulation all foxes in captivity for awhile to let population rebound island mice respond to direct cue of the predator essentially fox is only predator as number of foxes inc rodents become more paranoid suggests rodents know risk level and respond to it ecology of fear o also known as o non consumptive effects o risk effects o trait mediated effects o risk alone can change prey activity growth fecundity density capable of changing population sizes of prey Lec 2 2 17 15 ecology of fear risk effects non consumptive effects o can compare non consumptive effects with consumptive effects o strength of non consuptive effects was often at least as strong as consumptive effects fear goes a long way in animal behavior activity density growth rate fecundity etc hunting mode o identity of a predator isn t as relevant as how they hunt their prey tells prey more about their risk based on predator cue o sit and pursue predator vs active predators SAP let you run by and come after you cue from SAP likely right by it AP always looking around cue from AP may or may not be near activity somewhat dec in presence of both presence cues density growth and fecundity dec more in presence of cues from SAP predators than in presence of AP predators may be short term response to long term risk differences in growth and fecundity are more long term signifiers o perceived predation risk study kept all real predators away pulsed fear but not actual consumption in presence of predator cue changed nest location to thorny area short flight initiation distance more paranoid didn t sit on eggs as long spent more time off nest significantly less visits to feed nest fecundity in presence of predator cue lower total number of offspring eggs laid larger number of death of nestlings and eggs failed to hatch risk of predation changes bird population sizes and fitness plants and perceived cues o induced defensives plant becomes less tasty once it senses predator is attacked by predator gets bitten grows thorns o exposed plants to mucus as seeds and as seedlings cue was water or water and mucus benefit to plant is info to prep for attack before it happens o repeated exposure leads to a significant reduction in snail herbivory regardless of exposure as a seed o most pronounce defenses when experienced predator cue more frequently o changes in organismal behavior caused by predation risk affects fecundity growth crypsis and masquerade o crypsis hoping not to be recognized at all doesn t require predator experience jays made many more mistakes when moths were presented on a cryptic background evidence that crypsis works if can increase searching handling time of predator could be removed from diet good for prey variation in fur coloration in subspecies in different geographic areas concealed conspicuousness once seen by predator then have alternate defense masquerade hoping you will be recognized but will be mistaken as something o else o o requires experience in
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