Fecundity selection

[1] Charles Darwin formulated the theory of fecundity selection between 1871 and 1874 to explain the widespread evolution of female-biased sexual size dimorphism (SSD), where females were larger than males.

Fecundity selection is distinct[3] in that large female size relates to the ability to accommodate more offspring, and a higher capacity for energy storage to be invested in reproduction.

[4][5] Examples of fecundity selection in nature include self-incompatibility flowering plants, where pollen of some potential mates are not effective in forming seed,[6] as well as bird, lizard, fly, and butterfly and moth species that are spread across an ecological gradient.

[11] David Lack suggested in 1954 that differential food availability and management across latitudes play a role in offspring and parental fitness.

[13] Food differences in availability between seasons are greater towards higher latitudes, so birds are predicted to experience low survival during the winter due to limited resources.

Long breeding seasons towards the tropics favor smaller clutches since females are able to balance energy reserved for reproduction, and the risk of predation.

[1][16] Fecundity selection acts by favoring early reproduction and higher clutch size in species that reproduce frequently.

The strategy suggests that fewer, but larger, clutches in higher latitudes are a result of food seasonality, nest predation, and LBS.

[8] Liolaemus species span from the Atacama Desert to austral rain forests and Patagonia, and across a wide range of altitudes.

[7] Natural selection is defined as the differential survival and/or reproduction of organisms as a function of their physical attributes, where their 'fitness' is the ability to adapt to the environment and produce more (fertile) offspring.