BIOE 20C Lecture Notes - Lecture 15: Agonistic Behaviour, Aposematism, Herbivore
12 May 2018
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Ant - Plant Interactions
• Acacia trees: provide home to ants, sometimes food
• Ants: defend trees from grazers
• Plants with ants demonstrate better survival growth
Consumption (agonistic interactions)
• One species consumes all or part of another
• 3 types
o Herbivory
▪ Grazing organisms consume plant tissue
o Parasitism
▪ Parasite consumes relatively small amounts of tissue from a plant or
animal
o Predation
▪ Predator kills and consumes most or all of another organism
Defense from consumption
• Prey evolve defenses to counter predators
• Two basic types of defenses
o Constitutive: always presented
o Inducible: produced in response to predators
• Weaponry: fighting back
Certain defenses are advertised
• Aposematism:
o Warning coloration that advertise defenses
o Ex. bright colors, striped patterns
Mimicry
• Constitutive defenses have led to 2 types of mimicry
• Mullerian mimicry
o Species with similar defenses resemble each other
• Batesian mimicry
o Don't have a defense but resemble a species that does have a defense
Inducible defenses
• Variable responses
• Triggered by presence of predators
• Defense represents a fitness cost
• Inducible defense minimizes fitness cost
Top down vs bottom up control consumption
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Document Summary
Ant - plant interactions: acacia trees: provide home to ants, sometimes food, ants: defend trees from grazers, plants with ants demonstrate better survival growth. Defense from consumption: prey evolve defenses to counter predators, two basic types of defenses, constitutive: always presented. Inducible: produced in response to predators: weaponry: fighting back. Certain defenses are advertised: aposematism, warning coloration that advertise defenses, ex. bright colors, striped patterns. Mimicry: constitutive defenses have led to 2 types of mimicry, mullerian mimicry, species with similar defenses resemble each other, batesian mimicry, don"t have a defense but resemble a species that does have a defense. Inducible defenses: variable responses, triggered by presence of predators, defense represents a fitness cost. Top down vs bottom up control consumption: predator/prey populations undergo cycles, what controls these cycles, bottom up: amount of prey regulates predator abundance, top down: predators control prey abundance. Remoras and large fish/ whales: remora gets protection, food scraps, free ride, host not affected.
