Mating in most species involves a conflict of interest between males and females. Males have evolved many ways of persuading, coercing and even forcing females to mate with them. Females lay their eggs on the seaweed and the larvae feed on the bacteria that decompose it. Prolonged absences of seaweed occur on most beaches inhabitated by coelopids, with females often having to survive for long periods before suitable egg laying sites become available. The coelopid mating system is characterized by a premating struggle during which the female attempts to physically remove a mounted male by kicking and shaking, whilst curling their abdomens downwards in order to prevent the male from engaging genitalia.
Large males gain a mating advantage.