Parental Investment Theory
https://contensis.uwaterloo.ca/sites/courses/PSYCH-101/lecture-content/module-3/3c.aspx
This is really interesting stuff.
Parental InvestmentĀ is any expenditure (time, energy, resources etc.) that benefits an offspring and simultaneously reduces the parentās ability to invest in other aspects of fitness (e.g., mating).
Parental Investment TheoryĀ recognizes that there are asymmetries in the degree to which males and females of a given species are obligated to invest in offspring. That is, what male and females must invest to ensure successful reproduction. At the minimum, for instance, females areĀ obligatedĀ to invest an egg whereas males are obligated to invest sperm.
Trivers recognized that these asymmetries could be used to predict which sex would be more competitive and which sex would be choosier.
- The sex that makes the larger obligatory investment will be choosier when selecting a partner for mating.
- The sex that makes the smaller obligatory investment will compete for access to the sex that makes the larger investment.
OMG, PIT is sexist
no. this is facts. Parental Investment Theory perfectly predicts the mating practices of every known sexually reproducing species on our planet. There are zero exceptions to the rule.
In sea horses, for instance, females deposit their eggs into the maleās pouch where they are fertilized, carried, and cared for by the male until the offspring are ready to disperse. In this case, it is the males who are obligated to invest more and it is the males who become choosy. Male sea horses are very particular regarding which females are allowed to deposit their eggs in his pouch. And it is the females who are larger, more aggressive, and who compete with each other for access to the males.
