Parental Investment Flashcards
Why do females generally care more than males?
More direct fitness return on initial investment
Often a greater cost of desertion
Higher confidence of genetic parentage
How can offspring number/fitness be optimised?
Greater investment in offspring means they are more likely to survive.
Give an example where male quality can be assured
In captive male mallards, supplementing them with carotenoids increases the bill’s colour, brightness and hue. This signifies they are better are foraging. Males with brighter bills produced bigger eggs and clutch sizes.
How can parent-offspring conflict arise?
There can be conflict over optimal parental investment levels. Offspring is 100% related to itself but only 50% related to the parent.
When does parental investment stop and the parent starts investing in itself or future offspring?
Why are sex ratios evolved at 50:50?
If one sex is produced in lower numbers, that sex becomes the rarer mating type in the population.
The rarer sex will then enjoy greater reproductive success.
Selection will then act on increasing production of the rarer sex.
Ratio returned to 50:50
What is the Trivers-Willard theory of sex allocation?
As males often have a higher reproductive potential and variance than females, better conditions should favour investment in sons to enable realisation of potential.
E.g. if large male body size is an advantage, if you are going to produce a large offspring, it is better off to make it a son which will out reproduce a daughter.
Higher socially ranking deer on the isle of rum produce more sons.
However there is a trade off, red deer hinds take 11 days longer to come into oestrous OR miss an entire season after producing a more costly son.
