Cannibalism

Definition

The consumption of conspecific individuals as food; an intraspecific predatory interaction that functions as a density-dependent population regulator and alternative foraging strategy. In arthropods, cannibalism commonly occurs under resource limitation, high population density, or when size asymmetries allow larger individuals to prey upon smaller life stages (eggs, neonates, or molting individuals).

Etymology

From Spanish Caníbales, a name for the Carib people of the West Indies, via Latin canis (dog) folk etymology; applied to animal behavior in ecological literature since the early 20th century.

Example

In the European earwig Forficula auricularia, females frequently consume their own eggs when food is scarce—a facultative maternal cannibalism that trades off current versus future reproductive success. In predatory mites (Phytoseiidae), cannibalism of eggs and larvae by adult females is routine and can stabilize population oscillations in biological control systems.

Synonyms

• intraguild predation (when conspecific)
• autocannibalism (self-cannibalism, restricted usage)

Related Terms

• Predation
• kin recognition
• siblicide
• Trophic egg
• life-history trade-off
• Population regulation
• density-dependent mortality

Usage Notes

Distinguish from heterospecific predation and scavenging (cannibalism requires living or freshly killed conspecific prey). 'Facultative cannibalism' occurs when environmental conditions trigger the behavior; 'obligate cannibalism' is developmentally required, as in some mantid species where nymphs cannot complete development without conspecific prey. Size-structured cannibalism—larger stages consuming smaller—is particularly common in insects with marked ontogenetic size variation and incomplete metamorphosis. The term is sometimes extended to oophagy (egg-eating) and filial cannibalism (offspring consumption by parents), though specialists may treat these as distinct subcategories.