Evidence that 3-keto petromyzonol sulphate specifically attracts ovulating female sea lamprey, Petromyzon marinus

Abstract

We examined and confirmed the hypothesis that 3-keto petromyzonol sulphate (3kPZS) constitutes a major component of a male sea lamprey sex pheromone. Previous studies have indicated that male sea lampreys release 3kPZS after spermiation, and that 3kPZS specifically influences the behaviour of ovulating females. In this study, we addressed two issues to further characterize the function of 3kPZS: (1) whether the male pheromone specifically influences the behaviour of ovulating females only, and (2) whether synthetic 3kPZS replicates the function of the male pheromone in a natural environment. When placed in a two-choice maze, ovulating females preferred and showed search behaviours in the side scented with spermiating males, or washings thereof. Similar behavioural responses to the spermiating male odorant were not observed in males or preovulating females. Odorants from prespermiating males did not elicit similar behaviours from ovulating females. Furthermore, when released into a natural spawning stream, ovulating females located and swam to the source of water conditioned with spermiating males, or 10−12 M synthetic 3kPZS. This knowledge has the potential to impact the integrated management of sea lampreys in the Laurentian Great Lakes.