Interspecific Interactions Overview

Interspecific Interactions

• Interspecific interactions can be categorized by their effect on each species
• +/-: Consumer-Resource (e.g., predator-prey, parasite-host, parasitoid-host, herbivore-plant, grazing vs. browsing, seed predator)
• -/-: Competition
• +/+: Mutualism
• +/0: Commensalism
• -/0: Amensalism

Consumer-Resource

• Predator-prey
• Parasite-host
• Parasitoid-host
• Herbivore-plant
  • Grazing vs. browsing
  • Seed predator

Predation

• Predation is a consumer-resource interaction where one organism hunts and consumes another -Examples include images of a bird of prey with caught fish and a snake with a frog in its mouth

Parasitism

• Parasitism is a consumer-resource interaction in which one organism (parasite) harms another (host) without immediately killing it.
• Often symbiotic
• Symbiosis means two species live in close physical association
• Ectoparasite: lives externally on the host's body surface or outside the host's body
• Endoparasite: lives inside tissues of the host
• Parasitism differs from predation as it does not kill the host (e.g., flu/ viruses)
• Examples of blood-consuming human parasites:
  • Free-living: mosquitoes, leeches, ticks
  • Symbiotic: fleas, lice, malaria.
• Tapeworm life cycle: Cysts in raw meat; larvae form in muscle tissue; eggs hatch to larva and infect animal muscle; Adult tapeworm(8-11ft) in the small intestine; tapeworm head (scolex) attaches to intestine; Eggs contaminate vegetation, ingested by livestock

Parasitoid

• Parasitoid: Insect whose larvae consume and kill the host (e.g., Nasonia etc.)
  • Tarantula hawk (Pepsis spp.)

Herbivory

• Grazing: grass/herbs
• Browsing: woody vegetation
• Is the plant-animal version of what?

Seed Predator (Granivore)

• Example: chipmunk eating a nut, toucan eating a seed

Defensive Mechanisms

• Ways to avoid predation:
  • Early detection and swift escape
  • Camouflage (crypsis)
  • Chemical defense (animals and plants)
  • Protection: spines (porcupine), thorns (plants)
  • Warning coloration (aposematic)

Predator Avoidance Costs

• Studies (graphs) on the costs of predator avoidance for bullfrog tadpoles
• These costs include: Time spent not feeding, growth rates

Cryptic Coloration

• Crypsis: Camouflage (examples: insects, lizards, plants, lithops)

Western Coral Snake

• Picture of the snake.
• Aposematic warning coloration (bright colors warning of toxicity)

Mullerian Mimicry

• Poisonous animals mimic each other's color patterns
  • Examples include the pictures of wasps, honeybees, yellow jackets
• What kind of interaction is this?
• There's a study on poison dart frogs of Northern Peru

Batesian Mimicry

• Non-toxic animals mimic the color patterns of toxic or dangerous forms
  • Examples include pictures of a wasp, mantis, and a moth
• What kind of interaction?

Plant Defense

• Structural: Spines, bark
• Chemical: Secondary compounds not directly related to metabolism/photosynthesis
  • Lignin (indigestible)
  • Morphine, nicotine (poison)
  • Latex (poison/ gum up mouthparts)
• Examples of studies on milkweed, effects of herbivores on plants

Constitutive vs. Induced Plant Defense

• Constitutive: Always produced
• Induced: Occur after defoliation

Competition

• Intraspecific: Individuals of the same species
• Interspecific: Individuals of different species
  • Interference: Direct interaction (physical aggression, territorial fights)
  • Exploitative: Depleting shared resources (e.g., bats, hummingbirds, and nectar)

Mutualism

• Trophic: Complementary ways of receiving food (e.g., cows and cellulose, giant tubeworms and bacteria)
• Defensive: Defend each other; Example: cleaning mutualism (removes parasites from fish)
• Dispersive: Transport pollen or seeds (e.g., honeyguides and humans) -Seed dispersal benefits?

Commensalism

• Antbirds and Army ants
• Remora (suckerfish)
• Epiphytes (e.g., orchids, bromeliads)

Amensalism

• Example of fungus (Penicillium) affecting bacterial growth.

Explore the various types of interspecific interactions, including consumer-resource dynamics such as predation, parasitism, and competition. This quiz will test your understanding of how these interactions shape ecosystems and species relationships. Gain insights into mutualism and commensalism as well.