Behavioral Ecology Flashcards
Shared vigilance
More eyes. Each individual in a group must spend less time watching and can spend more time feeding.
Groups
Purposeful joining of individuals. Increase the chance of surviving, feeding, or finding a mate. Increased rate of resource depletion. Optimal grouping behavior balances these factors.
Shared defense
Group attacks on potential predator in a group.
Numerical Dilution Effect
reduced probability of predation for an individual during a successful attack on a group.
Confusion Effect
Difficult for predators to focus on one out of many moving prey
Benefits of groups in mating
Large groups attract the attention of females.
Lek
Place animals aggregate, display and attract the opposite sex
Territory and dominance hierarchies
Organize resource access. Dominant individuals get more
Interactions in a group require …
energy
Spitefulness
Maladaptive. Reduces the fitness of both donor and recipient. Not observed in natural populations
Selfishness
Donor experiences increased fitness, recipient experiences decreased fitness. Ex. Intraspecific competition for space.
Cooperation
Donor and recipient both experience increased fitness. Cooperation is common. Hunting, heat conservation, feeding by two parents.
REVIEW THE GAME THEORY PAY-OFF GRID FROM DISCUSSION
REVIEW THE GAME THEORY PAY-OFF GRID FROM DISCUSSION
Altruism
Cost to donor. Benefit to recipient. Selfless behavior. Does not lead to direct fitness. The fitness an individual gains by passing on genes to its offspring. We would expect selfishness to prevail over altruism.
Altruism is really … because …
Apparent altruism. The idea that altruistic acts may actually be cooperative. The donor may eventually benefit. Two main mechanisms proposed (reciprocal, kin)
Reciprocal altruism
Expectation that the other organism will act in a similar manner at a later time.
Kin selection
Altruistic behavior increases the fitness of a relative and in so doing indirectly increases the fitness of the altruist
Indirect fitness
the fitness an individual gains through the reproduction of their relatives which passes on copies of their genes (can be increased by helping behaviors).
Inclusive fitness
The mathematical sum of direct and indirect fitness.
Hamilton’s Rule
Benefit to the genes of the donor must be greater than the cost.
Hamilton’s equation
r > C/B
Eusociality
Highest grade of sociality. Most offspring help parents rear siblings rather than reproduce themselves. Some organisms have no direct fitness, only indirect (& thus inclusive) fitness. Cooperation not altruism. Reproductive dominance and sterile castes.
Eusocial Hymenopteran Societies
Many (not all) bees, wasps, and ants
Characteristics of Eusocial Hymenopteran Societies
One or a few egg-laying female queens. Non-reproductive female workers gather food and care for younger siblings Male offspring (drones) and new queens sexually mature and leave the nest.
Haplodiploidy in Hymenoptera
Daughter egg is fertilized by drone which is diploid. Drones come from unfertilized egg and is haploid. Drones must give some DNA to all daughters. Hymenopteron sisters are 0.75 in relatedness so it makes sense for the worker bees to be sterile and raise queen offspring.
True or false: Haplodiploidy is necessary for eusociality
False. It is favored but not necessary.
Diploid Eusocial Species
Termites, mole rates
Eusociality also favored when cost of staying with a colony is … and cost of leaving due to mortality is …
low, high
