Intermolt Insemination, an Alternative Mating Strategy for the American Lobster (Homarus americanus)

American lobster (Homarus americanus) have a dual mating strategy. Although most females mate when they are newly molted, mating can occur at any molt stage if necessary, in the laboratory, virtually all uninseminated preovigerous females mate prior to spawning. Male aggression is a major factor in the success of intermolt mating and males can discriminate between immature and mature females, and between inseminated and uninseminated females. Female receptivity is affected by both ovarian stage and the presence of stored sperm, but not by molt stage. Most females become unreceptive after insemination, but their receptivity returns once the supply of stored sperm is exhausted. Intermolt mating occurs in smaller lobster that for some reason did not mate at molt, and it is an important part of the reproductive strategy of larger lobster. Lobster s[Formula: see text] carapace length frequently spawn twice without molting and often fail to store sufficient sperm to fertilize consecutive spawnings. Intermolt mating ensures these females will produce fertile second broods.