Polygyny threshold model

The given shapes of the curve will change with other intrinsic factors like genetic quality and male paternal investment.

This represents the fitness gain of a female who chooses monogamy over bigamy due to, here, resource holding differences.

Orians predicted that animals exhibiting resource defence polygyny, such as the fish Neolamprologus pulcher would fit to this model when living in successive habitats, where territory quality is very variable.

Costs include less parental care and increased competition between females for the male's provision and food among other resources.

However, in a later study by Pribil and Picman conducted on Ontario populations of red-winged blackbirds the results indicated that there was indeed a cost of polygyny.

[4] Davies, Krebs, and West, in their textbook An Introduction to Behavioural Ecology, cited another Pribil study noting the polygyny cost to the red-winged blackbird females.

[7] Johnson, Kermott, and Lien conducted a study on the house wren (Troglodytes aedon) showing that there were inherent polygyny costs to these female populations, also.

The secondary females lost more of the broods largely because of starvation, and they also experienced lesser reproductive success in other areas.

Studies in human populations have demonstrated a decline of polygyny in highly stratified societies where rival wealth is concentrated by a small class of rich elite (economic inequality).