Chapter 12 Flashcards
What is Predation
A trophic interaction where individuals of one species (Predator) consumes individuals or parts of another species (Prey)
Parasitism
Parasite (predator) living in symbiosis (close physical/physiological contact) with its host (prey)
Parasitoid
Insects that lay eggs in another insect (host)
How do carnivore and herbivore nitrogen content differ
Plants have lower nitrogen and are less nutritious
Optimal foraging and dietary preferences are dependent on two factors:
Encounter rate (function of search time of predators for prey) and handling time (subduing and consuming prey)
If encounter rate is low
prey may be mobile and predators may generalists with broad diets
If encounter rate is high, but handling time is long
prey is most likely immobile, less nutritious plants
Example of carnivore showing preference (specialist)
lynxes and coyotes eat hares as their preferred prey, even when hairs are only 20% abundant, they make 60-80% of the lynx and coyote diet
Example of carnivore eating on availability (generalist)
guppies supplied with fruit flies and tubificids, guppies ate whatever was most abundant due to learning most common prey type.
Example of below ground herbivory being detrimental for plants
40% reduction in growth in bush lupine after 3 months of herbivory by caterpillars of ghost moths
Three methods of foraging
Movement (Hunters like wolf or sharks), Ambushing (Eels and snakes)
Traps (Spiders web)
Example of predators having traits improving ability to feed
Protist lembadio bullinum adjusts size depending on prey, and Garter snake detoxify prey chemical defense due to poison tolerance
Traits of prey to reduce predators consumption rate
Large size, rapid or agile movement body plan, body armor
Warning (aposematic) coloration
can provide protection from predators that instinctually avoid bright prey
Mimicry
when prey resemble less palatable organisms or physical features off the environment, making them appear less desirable to eat
Compensation
occurs when removal of plant tissues stimulates plant to produce new tissues
Induced defense
stimulated responses, such as cacti who increase production of spines after being grazed
Secondary compound
act to reduce herbivory, some are toxic, while some attract predators or parasitoids to the plant, where they attack herbivores
How do herbivores combat plant protective mechanisms
Some evolved digestive enzymes that tolerate or disarm chemical defenses, giving them an advantage or use behavior responses
What test did Zust conduct on aphids
Zust tested to prove that aphids (herbivores) present strong (natural) selection on the annual plant arabidopsis thaliana (mustard plant).
What were the results of Zust aphid experiment
Zust found that feeding by aphids reduced plant size by up to 82% when compared to control and ten plant genotypes were lost completely as different aphid species selected different plant genotypes
Lotka volterra predator prey model
represents the dynamics of predator prey interactions and aids in evaluating population cycles
Lotka Volterra Predator Prey Model Equation
dN/dt = rN - aNP
N
number of prey individuals
