Lecture 7: Sperm Competition Flashcards
who are Geoff Parker & Bob Trivers
In late 1960’s.
-GP = introduced concept of sperm competition
Both studied individual selection
Individual selection refers to which of tinbergens questions
FUNCTION
the adaptive significance of behaviour
–> (Function refers to the adaptive value or contribution that the behavior makes to fitness.)
sexual selection –> Post-copulatory sexual selection - sperm competition definition
Competition between the ejaculates of two or more males for the ova of a single female
what was Darwins view of sexual selection?
- discovered it but
- he assumed monogamy
- sexual selection was about mate acquisition only
In yellow dung flies what was it that G.A. Parker saw:
i) female yellow dungflies mate with more than one male = sperm competition, and
ii) males guarded females they had mated with
so SEXUAL SELECTION CONTIUNES AFTER MATING
Extra pair copulations adaptive? When are female birds fertile?
Hard to tell as birds & insects can store sperm (birds several weeks, insects several years in some cases) copulation a long time before can still fertilise
Is EPC adaptive for males?
Males engaged in extra pair copulations leave more offspring more copies of their genes
is EPC adaptive for females?
More problematical, As yet no concsensus of what benefits might be of females engaging in EPC
Cryptic female choose
- sexual selection taking place after copulation
- in ducks, when forced extra pair copulation takes place
- Strong circumstantial evidence that in ducks female reproductive anatomy has co-evolved with that of males in response to post-copulatory sexual selection
how did they use to determine paternity? (Zebra finch)
-Use to use genetic plumage markers to assign paternity
–Fawn genotype is a sex-linked recessive, so using only fawn females.. with a fawn male gives only fawn offspring, with grey (wild type) male gives only grey offspring
-Molecular methods
Multi-locus DNA fingerprinting - wild zebra finches in Australia
