Behavioural Ecology

behavioural ecology

interactions between organisms and their environment which are mediated by behaviour

focuses on animals but has expanded to plants/microbes

behaviour

the internally coordinated responses of whole living organisms to external or internal stimuli

what causes adaptive behaviours

can vary between species (interspecific) or within (intraspecific)

when certain behaviours may increase the survival and reproductive output of an organism, as well as being related to genotype (genetic basis) - it can be selected for/shaped by natural selection

adaptive behaviours

a behaviour which increases the fitness of an organism and will be selected for over multiple generations

operate in a range of conditions and depend on genes and the environment

as well as cognitive ability to learn

behaviours and genetic basis ex

distribution of work based on age in bees - younger bees inside as brood care, older bees forage outside

foraging behaviour coded by single gene which produces a specific protein (PKG)

so change in expression of one gene can alter behaviour

hamiltons classes of social interaction

based on fitness consequences:

cooperation, altruism, selfishness, spite

cooperation

both the donor and recipient have fitness benefits, generally within a species/related animals, exchange of resources

ex wolf pack, ants, bees, clownfish

hamiltons class of social interaction

altruism

recipient gets benefits, donor will not

ex ground squirrels will alarm call when risk of predation, red squirrels can adopt offspring

due to group selection, manipulation, reciprocal altruism, or kin selection

hamiltons class of social interaction

selfishness

donor benefits, recipient does not

ex male lions killing cubs from other males, cowbirds and their brood parasitism

in herds they stick close together as a way to get away from predators - better them vs you (not cooperative)

hamiltons class of social interaction

spite

neither donor or recipient will benefit

ex european badger infected with tuberculosis will often leave kin (fitness disadvantage) and also spread pathogen to non-kin

hamiltons class of social interaction

fitness

the number of offspring contributed by an individual relative to the number of offspring produced by other population members

inclusive fitness

an individuals overall fitness is determined by its survival and reproduction, and the survival and reproduction of its relatives

natural selection favours behaviours which increase this

cooperation and selfishness

should be selected for by natural selection because they increase donor fitness

altruism and spite

should be selected against by natural selection because they decrease donor fitness

group selection and altruism

individuals neglect their own needs in favour of the needs of the group

manipulation and altruism

donor does not recognize it is being parasitized

reciprocal altruism and altruism

recipient will pay back at one point in the future

kin selection and altruism

individuals increase their inclusive fitness by helping increase the survival and reproduction of relatives

coefficient of the relationship (Rg)

coefficient of the relationship (Rg)

the probability that the alleles at a given locus will be identical by descent among two individuals in the population

50% reduction between each additional connection

ex parent 50%, grandparent to child - 25%

coefficient of the relationship and altruism

Rg x B > C, Rg X B - C >0

the more distant the relationship (Rg) the larger the benefits must be to the recipient to outweigh the cost (to the donor)

but when the relationship is closer, the benefits dont have the be as large to outweigh costs

obligate brood parasite

species must lay eggs in the nests of other birds

can be intra or interspecific

cowbirds and phoebe birds

selfish from the pov of the cowbird

but altrustic from the pov of the phoebe who raises another one’s young

considered manipulation because she has no means to prevent or recognize the act

sociality

consists of a group of individuals living together

evolution is supported by cooperative feeding, defense of social group, restricted reproductive opps

strong kin selection

ex mutual grooing, protection of young, alloparenting/allonursing, highly complex societies

wolf packs and sociality

alpha male and female are the only ones reproducing, this restricts the opportunities of other wolves and so they care for the young

cooperative breeders

live in groups, several adults help with offspring

defense, prepare/maintain living area, feed young

works because of inclusive fitness - most likely relatives, reciprocal altruism - u help me i help u

but can develop inbreeding

eusocial animals

highly complex social behaviour which evolved independently

individuals of more than 1 generation live together, cooperative care of young, division of individuals into sterile/non-reproductive and reproductive castes

ex leafcutter ants (7 castes), naked mole rats (3)

castes

generally likely to have larger workers specializing in defense (sterile), then there are smaller ones in foraging and maintenance - convergent evolution

queen on top

why has eusociality evolved?

kin selection due to very high degree of relatedness - haplodiploidy

ecological restraints

haplodiploidy

sisters are more related to eachother (75%) than they are to their brothers (50%)

also then they would be to their own offspring (50%)

this means makes more sense to raise a sister than to raise a new