Behavioral Ecology - Resource Competition

What does the Evolutionarily Stable Strategy (ESS) state?

A strategy that if all members of a population adopt it, cannot be bettered by an alternative strategy

What is the hawk-dove equation?

If V > C then V/C

What would the ESS be if V = 40 and C = 60? What would the ESS be if V = 40 and C = 10?

1) 2/3
2) 1; the ESS is for the population to be all hawks

What is the difference between producers and scroungers?

Producers: Make food available by exposing prey

Scroungers: Steal food found by producers

What are four reasons why fighters don’t confront sneaks?

1) Too energetically expensive
2) They’re too busy fighting with other conspecifics
3) Removes their good positionality to mate with females
4) Sneaks may not decrease the fitness of the fighters

What is the difference between competition by exploitation/ideal free model vs competition by resource defense/despotic distribution?

In competition by exploitation, there’s no territoriality or fighting; individuals can choose wherever they want to forage because there’s abundant resources in both rich and poor habitats to sustain all animals equally. Ex: Stickleback fish

In competition by resource defense, species keep others away from resources through dominance or territoriality. First arriving competitors settle in rich habitat an defend their territory, while later arriving competitors are forced to settle in poor areas even though they do less well there. Ex: Great tits

What are six species that are producers/scroungers or fighter/sneaks due to environmental factors?

1) Ruddy turnstones: Body condition likely impacts whether producer or scrounger
2) Spice finches: Environment impacts whether producer or scrounger
3) Toads: Younger (smaller) toads are sneaks
4) Horseshoe crabs: Crabs in poor physical condition are sneaks
5) Switch flexibly between being producer or scrounger
6) Dung beetles: Beetles that got fed poorer diets as larvae are sneaks

What are two species that are fighter/sneaks due to genetic factors?

1) Marine isopods: Three morphs; large “alpha” males, small “beta” males (look like sexually mature females), tiny “gamma” males
2) Ruffs: Males have two morphs; dark ruffs love to fight (independents) while white ruffs don’t fight and act as satellites on edge of territories and try to sneak copulations