130 likes | 227 Vues
Other chemical defense. Bees: Stingers Isoamyl Acetate Ants: Formic acid. Actually, at least 11 hypotheses have been proposed. T. Caro has observed more than 200 occasions in response to cheetahs: stotting gazelles have never been seen to be caught.
E N D
Other chemical defense • Bees: • Stingers • Isoamyl Acetate • Ants: • Formic acid
Actually, at least 11 hypotheses have been proposed. T. Caro has observed more than 200 occasions in response to cheetahs: stotting gazelles have never been seen to be caught. gazelles stott to proclaim to the cheetah that it has been detected and no longer has surprise in its favor. Cheetahs often do give up after stotting.
The rewards of social living Flock vigilance, dilution effects and selfish herds • Flock vigilance: 2 eyes are better than one • Dilution effects: you cant eat us all • Selfish herds: surround yourself with food Vigilance
Vigilance behavior can be conditional on risk • House sparrows chirp (attracting) more when risk is low • Is this a selfish behavior?
Dilution effect: While living in a group may attract more predators the net individual risk is reduced Whirligig beetles