Predator-Prey Interactions Flashcards
What is the red queen hypothesis?
“Continuing adaptation is needed in order for a species to maintain its relative fitness amongst the systems it is co-evolving with”
What are the selection pressures in predators?
Selection for improvements in foraging
What are the selection pressures in prey?
Selection for improvements in defences
What are the predator adaptations when searching for prey?
Improved visual acuity
Search image
Search limited area where prey abundant
What are the counter-adaptations by prey when predators are searching for them?
Crypsis (background matching, disruptive patterns and countershading)
Polymorphism
Space out
What are the predator adaptations in recognition of prey?
Learning
What are the counter-adaptations by prey when predators are recognising them?
Masquerade (resemble inedible objects)
Warning signals of toxicity (aposematism, Mullerian mimicry)
Deceive predators by mimicking defended prey
What are the predator adaptations in catching of prey?
Secretive approach
Motor skills (speed and agility)
Weapons of offence
What are the counter-adaptations by prey when predators are trying to catch them?
Signal to predator that it’s been detected Escape flight Startle response: eyespots Deflect attack Weapons of defence
What are the predator adaptions when handling prey?
Subduing skills
Detoxification ability
What are the counter-adaptations by prey when predators are handling them?
Active defence, spines, tough integuments
Toxins
What is camouflage?
All forms of concealment, including strategies that prevent detection (background matching) and those that prevent recognition (masquerade)
What are the two forms of camouflage?
Prevent detection: crypsis (background matching, countershading and disruptive colour)
Prevent recognition: masquerading
What is the purpose of background matching?
It makes searching for the prey more difficult for the predator because they do not match their pre-learned “search image”
What is countershading?
Animal counters the patterns of light and shade with body colouration: put the darker colours on parts of the body that are typically illuminated - enhances cryptic protection
What is disruptive colouration?
Disruptive coloration is a form of camouflage that works by breaking up the outlines of an animal with a strongly contrasting pattern
What is prey polymorphism?
It describes the survival of individual prey animals that are different (through mutation) from their species in a way that makes it more likely for them to be ignored by their predators. It operates on polymorphic species, species which have different forms.
What is apostatic selection?
Where predators overlook rare prey types and consume excess of abundant prey types
What is an example of apostatic selection?
Grouse locust - frequency dependent selection whereby the fitness of morph declines if it becomes too common in the population
What is masquerade?
Masquerade describes the resemblance of an organism to an inedible object and is hypothesised to facilitate misidentification of that organism by it’s predators or its prey.
How can you distinguish between masquerade and crypsis?
With crypsis, detection of the individual in the environment is reduced; With masquerade the predator detects the existence of the potential prey but then misidentifies it as something unattractive to eat.
What are aposematic signals?
Aposematic signals are primarily visual, using bright colours and high-contrast patterns such as stripes.
How do aposematic signals sometimes exploit aspects of predator psychology?
Wariness of certain colours/patterns
Capacity to learn
Memory retention of learnt avoidance
What is an example of when aposematism has been used in conjunction with spatial behaviour?
Brightly coloured species of caterpillars of British butterflies are more likely to be aggregated in family groups than cryptic species
What are the two types of mimicry?
Mullerian and Batesian
What is Mullerian mimicry?
Müllerian mimicry is a natural phenomenon in which two or more well-defended species, often foul-tasting and that share common predators, have come to mimic each other’s honest warning signals, to their mutual benefit.
What are potential examples of Mullerian mimicry?
Heliconius butterflies, European burnet moths, bumble bees, cotton Stainer bugs, poison arrow frogs, Appalachian millipedes.
What is an example of mimicry rings (pairs of multiple species)?
Butterflies
Prey benefits because predators learn avoidance more quickly.
Heliconius cydno has 2 forms, white and yellow.
Each form does better in sites where its model is more abundant
Butterflies released at 4 sites, control (solid line) resemble the model, experimental (dashed) do not.
What is Batesian mimicry?
Batesian mimicry is a form of mimicry where a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both.
What is the difference between Batesian and Mullerian mimicry?
Batesian mimicry is the exhibition of the characteristics of a dangerous species by a harmless species to avoid predators whereas Mullerian mimicry is the exhibition of similar characteristics by similar species to avoid predators
What is an example of when even poor mimics were good enough?
Coral snakes and nonvenomous scarlet king snakes: replicas of poor mimics were preyed on significantly more often than replicas of perfect and good mimics.
Perfect and good mimics experienced similar attack rates, despite having a different ring order.
Poor mimic – same colours, different proportions, different order
Good mimic – same colours, same proportions, different order
Poor mimic higher probability of attack
What is death feigning?
“Playing dead”
Death feigning versus flight
Animals like cuttlefish match their response (play dead or flee) to the threat level and predator type
