Kinship and Kin Recognition Flashcards
Discriminative Parenting in Bats
A 1962 study incorrectly determined that female bats could not recognize their own kin, and instead were “an anonymous dairy herd”. This turned out to be untrue, which isn’t surprising since it isn’t an ESS. Moms can accurately recognize their own pups by smell and auditory signals.
When should we expect Discriminative Parental Care mechanisms to evolve?
When parents are exposed to situations in which they might misdirect parental investment to the benefit of rivals’ fitness.
Discriminative Parental Care: Cliff Swallows vs. Barn Swallows
Cliff swallows nest colonially, and live in large aggregations. As such, they recognize their chicks by face and voice. Cliff swallow chicks’ voices are more distinctive to facilitate this.
Barn swallows nest dispersedly. As such, they do not have parental recognition.
Discriminative Parental Care in Sheep
Sheep inspect their lambs immediately at birth, learns its individual odour, and subsequently rejects all other lambs.
During the birthing process, an ewe’s olfactory system is reprogrammed. Mitral cells (which normally respond to food) respond only to the individual lamb they bond with at birth.
What sort of discriminations would we expect evolved parents to make?
Phenotypic quality (how will the offspring convert investment to fitness?)
Quantity and need (how much difference will this investment make?)
Identity (is this infant really mine?)
Inclusive Fitness = ?
Direct Fitness + Indirect Fitness
Coefficient of Relatedness
The % of genes that two individuals share by common descent.
r = Σ(0.5)^n
Hamilton’s Rule
(r x b) - c > 0
Where r = coefficient of relatedness, b = benefit to recipient, c = cost to actor.
Belding Ground Squirrels and Hamilton’s Rule
Females stay close to their natal burrow for their entire life, while males disperse. As such, females call significantly more than males, as they are often around those they are related to.
Kin Recognition
Ability to identify relatives, assessing genetic relatedness, differential treatment based on cues of relatedness.
Phenotypic label or cue is acted on by the perceptual system. It is then matched to some sort of template. Identification as kin can lead to nepotism, inbreeding avoidance, or increase in care.
Kin Selection
A form of natural selection. When individuals engage in self-sacrificial behaviour (lives, energy, fitness) that benefits the genetic fitness of relatives.
Mechanisms of Kin Recognition
- Location (indirect recognition): treat everyone in nest or burrow as kin.
- Association/familiarity (indirect recognition): treat any individual which you are associated or familiar with as kin.
- Phenotype matching (direct recognition): inspect and learn characteristics of relatives and use them as a recognition guide for unknown individuals.
- Self-referent phenotype matching (direct recognition): learning your own phenotype and comparing it to unknown individuals.
Cuckoos
Obligate brood parasites. Watch hosts, remove an egg once their clutch has been laid, and then leave one of their own (which mimics the rest of the clutch). Eggs have a shorter incubation time, and will hatch before the others, allowing the chick to monopolize resources and kick the others out.
They have redder mouths than their hosts. They match the calls of multiple chicks at once.
Counter-adaptations of Cuckoo Hosts
- Choosing nest sites that are hard to parasitize, territorial defense, group defense.
- Morning incubation (as many birds eat in the morning after not having eaten at night)
- Mottled eggs (distinct recognizable pattern)
- Ejection (puncture or grasp eggs) [may not be physically possible, or results in damage to own eggs]
- Brood desertion [costly to start a new clutch]
Conspecific Brood Parasitism and American Cootes
Commonly parasitized by other American Cootes. Parasitic chicks have a lower survival rate, because host chicks are normally born first. Experiments suggest chick recognition is learned after hatching of first few chicks.
