Social Behavior and group formation Flashcards
what are the disadvantages of group formation
- shared resources increase competition if resources are limited.
- more noticeable
- must invest energy in social behavior
- could cause increased inbreeding.
- reproductive suppression is typical within groups
why do organisms live in groups
most reasons revolve around an ecological basis.
what are the two main hypotheses for group formation?
- Predator avoidance and defense.
- increase in foraging efficiency.
Predator avoidance and defence
- more eyes and ears to look for predators, more individuals to help defend.
Increase in foraging efficiency
By living in a social group, you can rely on the memory of other individuals regarding the pattern of food and water availability in your home range.
- larger groups are able to defend resources better.
factors influencing group formation
- resource distribution
- predation risk
- intraspecific competition
what can the distribution of resources do to a group
- prohibit group formation
- promote group formation
- permit group formation while some other factor acts to puch group formation.
what does this mean for solitary or asocial species
often has something to do with the reasources needed that forces individuals to live and forage alone.
what are the effects of resource distribution?
- determines how far an organism must travel for food.
- in general higher quality food like fruit and insects are less abundant and tend to have patchier distribution.
- things like leaves are often abundant and have a uniform distribution.
- this means that organisms that are folivores do not have to travel as far to find food so they do not have to burn as many calories.
- with a patchy distribution of high-quality food, an organism has to travel further, burning more calories but can consume higher quality food.
what do organisms do when their preferred food is scarce?
- they have to switch to a less preferred food
- fission-fusion hunting in a group
- due to insects’ mobile nature, they have random distribution and are scarce, which makes it impossible for larger primates to rely on them.
what about for groups that are not formed because of resource distribtion
for grazers, group formation allows for safety because while some are feeding with their head down, the others can keep watch.
How are social groups organized
Females depend on food
- lactation and pregnancy are energetically expensive.
males depend on females
- for success in mating and passing on genes.
social relationships - female interactions
Female-female competition
female rank and mothering style
female boding
Female-Female competition
- more low-key bc of the presence of infants
- Direct contest over food = displacements
- indirect suppression or inhibition of ovulation via pheromones
- create allies/coalitions to support or cooperate against others: close vs. distant kin, matriline, intergroup contest.
Mothering styles
Permissive: are less restraining of their young
restrictive: are more protective of their young