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Peter Morrow

Antipredatory Behavior Outline • Primary Defenses • Secondary Defenses Primary Defense • A primary defense reduces the probability of attack – Camouflage – Counter-shading – Altering one’s appearance – Distraction – Mimicry – Group living Being conspicuous is a disadvantage Artificial color mutation: do red painted great tits experience increased or decreased Camouflage, be a rock Camouflage: Ibex being rock stars Camouflage: Tawny Frogmouth hunts at night but hides during daytime Camouflage: Cuttlefish (similar to the squid, a Cephalopod) waiting for its prey and avoiding predators Can be a source of protection as well as a predation advantage Camouflage: Dead leaf mantis waiting for its prey Camouflage: The rock fish, waiting for its prey Counter-shading • Many birds, fish and squids are darkly colored on their dorsal surface but a pale underneath . • Reduces the silhouette presented by the animal by reducing the effect of any shadows cast by the curve of the body surface due to light from above Counter -shading Counter-shading Altering one’s appearance • Predators develop search images • They learn to recognize their prey, experience individuals are able to recognize potential prey faster than their naïve counterparts What can prey animals do? • They can avoid predation by altering their phenotype and hampering the development of a search image Predator distraction displays • Remaining inconspicuous clearly has antipredatory benefits, however advertising your presence can be beneficial too. Deceptive strategies of the plover (Charadrius hiaticula ) •If predator is far, bird pretends to incubate (false nest) and then flies away, predator searches false nest area •In long grass bird mimics sound and movement of rodents to lure predator away from nest. •Bird may move towards the predator calling loudly, only changing direction at the last minute and thus managing to escape •Broken wing display: pretending to be hurt, bird leads predator away from the nest. Nesting Killdeer (Charadrius vociferus) pretends to have broken wings and lures predators away from the nest Mimicry • A deceptive signal, used for an antipredatory response in which, a prey species pretends to be a more dangerous or poisonous in order to avoid predation • 2 forms of mimicry: – Mullerian mimicry – Batesian mimicry Mullerian mimicry: common features honestly advertising same function in multiple species • The black and yellow pattern of wasps and caterpillars of moths: We are all poisonous! Paper wasp European wasp Wood wasp Callimorpha dominula Interspecific mimicry: dishonest signals Batesian Mimicry Looks like a wasp but it’s NOT!! Syrphus hoverflies are quite edible but will be avoided! Interspecific mimicry: dishonest signals The cleaner wrasse, Labroides dimidiatus, (top) is a symbiont removing ectoparasites from other fish, the mimic, a blenny, Aspidontus taeniatus, (bottom) bites off parts of other fishes' skin and fins. Distraction (the power in numbers): Schooling fish avoid predation by moving together The dilution effect, the idea that the larger the group the lower the probability that a single will be the target of a predator Synchronization of breeding in guillemots increases survival rate of their chicks Increasing flock size decreases probability of attack per prey in the redshank. Increasing flock size decreases time prey devotes to scanning for predators The advantages of sticking together • Decreased predatory risk (increased confusion for predators) – confusion effect • Decreased vigilance (energy and time devoted to watching out for predators) for prey The compromise between foraging and vigilance Factors influencing flock size: Optimization •Increasing flock size allows better detection, utilization of food up to a point. •Increasing flock size increases interference (costly interaction among members of the group. •Increasing group size decreases need for vigilance Vigilance: interspecific collaboration I can see but you need to help me smell I can’t see but will help you sniff out danger Mobbing • Surrounding a predator and constant
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