Salmon lice (Lepeophtheirus salmonis) are a specialist ectoparasite of salmonids. Interest in their reproductive biology derives from their outsized role in disrupting the marine Atlantic salmon aquaculture industry. Salmon lice can cause severe deleterious effects on their salmonid hosts and recurring seasonal infestations have had profound effects on the aquaculture industry.
Development of novel mitigation measures to control these pests is needed. Identifying pheromonal targets that have the potential to disrupt reproduction of the salmon lice could lead to the development of new treatments. As a dioecious parasite, salmon lice must identify the suitability of a mate. The species, sex, and reproductive state are important to determine prior to making the energetically costly decision to copulate. Recognition factors that are utilized to adjudicate pairing in L. salmonis are not known.
Copepods have been shown to use surface sex specific molecules, expressed in locations important for courtship and mating, as pheromonal indicators of reproductive suitability in a conspecific. In this study we explored the possibility that L. salmonis expresses surface molecules in areas of known pre-copular contact which may be utilized as contact sex pheromones. Through treatments we provide evidence that sex specific surface-bound molecules are present on the cuticle of L. salmonis in locations important for courtship and mating. The results of this study provide a potential novel basis for disruption of the salmon lice life cycle.