The main benefit of this action can only be an investment in the future reproduction of potentially larger or healthier broods.
[3] Competition among a species for resources, mating opportunities, and reproductive dominance are all promoters for filial cannibalism.
To compete well in a certain species' social structure, a parent may be compelled to practice filial cannibalism to limit the amount of energy and time they spend raising their young.
Females may also use cannibalism – particularly birds and bees that live in a joint-nesting social structure – as a way to establish reproductive dominance by eating the eggs of a co-breeder.
[3] In some animal cultures, competition may lead to instances of egg thievery, nest takeovers, and cuckoldry.
This is likely in order to gain additional energy and nutrients, which might ultimately increase their future reproductive success.
However, the acquisition of eggs suppresses the secretion of androgen, preventing males from performing courtship displays and obtaining more offspring.
At higher densities with insufficient food, larvae may not develop completely, resulting in smaller adults that are less likely to find a mate, as well as limiting the maximum clutch size that can be laid.
[14] Filial cannibalism can also serve as a source of energy while simultaneously removing nonviable eggs, such as those that have been parasitized.
R. tristis males also guard adopted broods without a higher rate of cannibalization, suggesting that they cannot discriminate between their own eggs and unrelated ones.