Spider cannibalism

Indeed, scholars have noted that the "supposed aggressiveness of the female spider towards the male is largely a myth" and that cannibalism only occurs in exceptional cases.

[4] Reversing the traditional roles, species that have males consuming females are relatively unknown; the few that do show a male-biased sexual dimorphism.

Juvenile redback spiders live in groups immediately after hatching, and are known to cannibalize siblings during this period.

This behavior may be triggered by aggression, where females carry over hostility from their juvenile state and consume males just as they would prey.

Known as the "aggressive spillover hypothesis", this tendency to unselectively attack anything that moves is cultivated by a positive correlation between hostility, foraging capability, and fecundity.

This behavior "spills over" into adulthood, and shows up as a nonadaptive trait that manifests itself through adult females preying on males of their same species.