Even in the Animal Kingdom, there are some common sense rules. The more likely to get a big return, for example, the more work will be invested. That goes for male-female relationships as well.
A French team of behavioral ecologists demonstrated that in the Peafowl. They found that females with attractive mates invested more resources in their eggs than females paired with unattractive mates. They laid larger eggs and deposited more testosterone in egg yolk, potentially offering a better prospective to their offspring.
Adeline Loyau, Michel Saint Jalme, Robert Mauget, and Gabriele Sorci of the National Museum of Natural History and the Laboratory of Evolutive Parasitology, Paris, investigated maternal investment in the peafowl (Pavo cristatus).