Parental care trade-offs and the role of filial cannibalism in the maritime earwig, Anisolabis maritima

► We measured the fitness costs and benefits of maternal care in the maritime earwig, Anisolabis maritima. ► Maternal care increased offspring survival seven-fold, but reduced subsequent clutch sizes. ► Females routinely reduced clutch size through filial cannibalism. ► We tested the function of filial cannibalism. ► Filial cannibalism may be a product of energy limitation and hygienic removal of unviable eggs.