Kinship and Kin recognition Flashcards
discriminative parental care
cognitive or physiological mechanisms will evolve for recognizing offspring, but only if there is risk of error.
breeding colonies of bats, after pup is born the mother hangs it from the cave roof and goes to forage. Moms recognize pup’s smells and sounds
swallows discrimination
cliff swallows- discriminate parental care. young often leave nest and move around, so parents will recognize chick’s voices and face before care. the chicks themselves have more variety in their sounds
barn swallows- non discriminate parental care. rare to find another chick in their nest, they’re very dispersed. no parental recognition, will accept fosters.
lambs discriminatory care
mother ewe will inspect her lamb at birth, learns its individual odour and rejects all other lambs so she’s not parasitized.
what sort of discriminations would parents make?
- phenotypic quality: can this offspring convert parental investment into parental fitness?
- quantity and need: how much difference will this investment make?
- identity: is this my offspring?
human examples of discrimination
parentage matters, more resources given to genetic offspring
offspring quality matters some parents may abandon or kill offspring
direct kin
offspring and grand offspring
other kin
any other relatives who arent direct descendants.
coefficient of relatedness
r.
% of genes that are shared by individuals of common descent.
r for parent to offspring?
0.5
r for grandparent - grandoffspring?
0.25
r for first cousins?
0.125
Hamilton’s Rule
if rB-c > 0, then altruism will occur
r=relatedness
B=benefit
c=costs
alarm calls
vocalizations that alert other animals to danger. callers usually suffer a cost because they draw attention to themselves, but others around them benefit since they can escape.
ground squirrels alarm calling
dispersal is sexually asymmetric. females remain close to natal burrow, but males disperse. females are expected to alarm call more since they are around more of their relatives.
kin recognition
the ability to identify relatives, and assess genetic relatedness. permits kin selection
kin selection
a form of natural selection, where individuals engage in self sacrificial behaviour that benefits the genetic fitness of relatives. Gives the actor indirect fitness.
kin recognition systems
production of kin phenotypic labels or cues
sensory perception of label and and comparison /matching
action by individual
kin recognition mechanisms in ground squirrels
odours from oral and dorsal glands.
they can discriminate based on scent, and can tell if they are kin even if they had never encountered the related individual.
explored non kin odours longer
sweaty t shirt study
women preferred the body odours of men who had dissimilar MHC genes from their own
4 mechanisms of kin recognition
location (indirect): treat any individual in nest as kin.
association/familiarity (indirect): treat any individual you are familiar with as kin. works if raised in family groups, so phenotypes are reliable cues
phenotype matching (direct): individuals inspect and learn certain phenotypes of their relatives and use these to recognize kin if encountering unknown individuals
self referent phenotype matching (armpit effect, direct): learn your phenotype, to later compare or match unknown phenotypes with your template
cuckoo tactics
brood parasites- keep watch over nest hosts and once eggs are laid, replace host’s egg with their own, which is colour matched. (Mimetic eggs)
brood parasite adaptations
must choose host species and time their egg laying, remove egg when they lay their own
mimetic eggs
short egg incubation time and fast chick growth rate
counter adaptation of brood parasite hosts
choose nest sites that are hard to parasitize, territory defence
morning incubation
mottled eggs (Distinct pattern)
ejection (puncture or grasp eggs)
brood desertion
host parasite arms race, cuckoos
cuckoos have different host races, and each race lays distinct eggs that best mimic their specific host.
