FÖ7 Avioding Predation, Finding Food & Habitat Selection (ch. 5-6)

Life-dinner principle

a characterization of the race between predators and prey that is meant to emphasize the supposed selective asymmetry between the players.

• It is more selectively important that the prey get away than for the hunter to succeed

Predation event

1. Detection

2. Identification

3. Attack

4. Capture

5. Consumption

Crypsis

the ability of an animal to avoid observation or detection by other animals

• Background matching

• Disruptive colouration

• Mimicry

Disruptive coloration

Irregular patches of contrasts that tend to catch the eye of predators and break up the outline of the animal, making it harder to detect

Camouflage by mimicry

An animal resembling something else to avoid detection

• Ex. looking like a plant, eyespots on butterflies to startle

Optimality theory

a framework that assumes natural selection favours behaviours that maximize an animal’s fitness given ecological constraints

• Works based on a cost-benefit analysis

• Mathematical models can be used to predict optimal strategies

• Problems:

  • Maximizing one behaviour can have a negative effect on another

  • Over time selection acts for an optimal trade-off between behaviours

  • Does not take behavioural syndromes (personality) into account

  • Neglects importance of learning as an optimization process

Carcinization

Repeated convergent evolution of crustaceans into crab-like bodies

Dispersal

movement of an animal from one site (birthplace) to another

Migration

population moving between locations regularly

• Seasonally sychronized relocations between breeding ground and wintering area

• When the same or different generations move within a breeding season (some insects)

• Movements in circuits between bredding, feeding and wintering sites (some fish)

IFD (Ideal Free Distribution)

Animals will distribute with such densities that a constant intake rate is achieved

A game theoretical model, used to predict distribution of individuals in space, assumes that:

• Behavioral decisions are assumed to maximize reproductive success, or some proxies such as energy gain, number of matings

• Individuals have perfect information about relative fitness payoffs and can move freely

• Individuals have equal competitive abilities, and can move between patches without costs

Cannot predict how the animals will distributed with only one measurement, it depends on what others are doing

• Intake rates should equalize between patches

Surface distribution model

Model that assumes that animals will distribute with equal densities over the total surface

Evolutionarily stable strategy (ESS)

A strategy that cannot be replaced by an alternative strategy because it would not be beneficial under natural selection