announcements. tarantula hawk red shouldered hawk emperor penguin parental care very costly behavior...
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Announcements
tarantula hawkred shouldered hawk
emperor penguin
Parental care
Very costly behavior - time- energy- vulnerable to predation
earwig
Sibling conflict
Sibling aggression and siblicide
Occurs when resources are variable or in short supply?
Offspring compete for resources (they only share 50% of genes)
Galapagos
masked booby
have two eggs, first hatched chick always kills second chick
blue-footed booby
have two eggs, often raise two young
Parent offspring conflict (Trivers)
Selection may act on parents and offspring differently.
Some actions that increase fitness of offspring may reduce fitness of parents.
Parental favoritism
Likely occurs when resources are variable and adults have more young than they can raise (bet hedging)
Females can invest in eggs differently (even choose sex in some species).
Young can be fed preferentially.
Seychelles warbler
Parental favoritism
Honest signals of quality in offspring?
barn swallows
Asynchrony in hatching (birth order) can promote or reduce sibling conflict and parental favoritism
great egret
Can parents control sex of offspring?
Seychelles Warbler
Can parents control sex of offspring?
Haplo / diploid organisms (like ants, bees and wasps)fertilized egg = female ; un-fertilized egg = male
Temperature Dependant Sex Determination (TSD)many reptiles
Helpers at the nest
In some animals, juveniles stay to help second nesting effort.
More often female juveniles.
Both direct and indirect benefits.
Direct (learning about maternal care) Indirect (inclusive fitness by helping rear related offspring
magpie jaysvoles
Helpers at the nest
Leads to overlapping generations
Key step in the evolution of sociality?
Genetics basis for mating systems / parental care.
prairie voles
Monogamous, male parental care
meadow voles
polygynous, no male parental care
In male prairie voles, vasopressin and dopamine in the forebrain regulate affiliation between mates (bond formation).
Vasopressin receptor is expressed at higher levels in monogamous species than polygynous species.
Lim and colleagues, used a viral vector to transfer the vasopressin receptor gene from the monogamous species into the polygynous species.
With this change in a single gene, the polygynous species essentially became monogamous.