The efficacy of two synthesized sea lamprey sex pheromone components as a trap lure when placed in direct competition with natural male odors

Abstract

The female sea lamprey (Petromyzon marinus), a devastating invasive fish of the Laurentian Great Lakes, locates potential mates by tracking a sex pheromone emitted by nesting males. We tested whether combinations of two putative components of the sex pheromone, 3-keto-petromyzonol sulfate (3kPZS) and 3-keto-allocholic acid (3kACA), were sufficiently attractive to function as a trap-bait when placed in direct competition with male odors. Ovulating females successfully located point sources of 3kPZS both in the presence and absence of a competing odor emitted by mature males placed upstream. However, 3kPZS was not able to retain females in the vicinity of a trap longer than two minutes, and retention time was reduced by 57% when competing male odors were present. 3kACA failed to elicit a response on its own and did not improve attraction to, or retention near, a source of 3kPZS. Application of an incomplete pheromone in trapping-for-control scenarios will require devices configured to minimize the effort necessary to enter a trap, features to offset the probable decrease in trap retention, and deployment into favorable habitats where competition with spawning males is minimal.

Multiple functions of a multi‐component mating pheromone in sea lamprey Petromyzon marinus

“…In electro‐olfactogram recordings, both 3kPZS and 3kACA are potent odorants in female P. marinus , probably by stimulating different olfactory receptor mechanisms (Siefkes & Li, 2004). While there is increasing evidence that 3kPZS induces overt upstream movement in females (Johnson et al , 2009), it remains to be determined whether 3kACA induces behavioural responses in females (Luehring et al , 2010). The first objective, therefore, was to determine if the C24 sulphate is critical for 3kPZS to induce upstream movement by determining if 3kACA modifies ovulated female behaviour in streams.…”

A Sea Lamprey (Petromyzon marinus) Sex Pheromone Mixture Increases Trap Catch Relative to a Single Synthesized Component in Specific Environments

“…For example, in Luehring et al (2011), ovulated females spent less time near 3kPZS-baited traps when caged spermiated males were located upstream. Lack of increased performance of SMW in capturing sea lampreys at spawning grounds may also be a result of the confounding effects of 'at-large' pheromone plumes.…”

“…recently has been identified (3,12-diketo-4,6-petromyzonene-24-sulfate; DKPES; Li et al 2013). However, when 3kPZS or mixtures of 3kPZS and DKPES were directly compared to the full male sex pheromone collected from live males (spermiated male washings; SMW), SMW attracted more females and retained females longer than synthesized odorants (Johnson et al 2009(Johnson et al , 2012Li et al 2013;Luehring et al 2011;Siefkes et al 2005). For example, when a mixture of 3kPZS and DKPES was compared directly to SMW in a controlled stream environment with no background sources of pheromone, two females visited the nest baited with 3kPZS and DKPES, while 12 females visited the nest with SMW .…”

“…Perhaps 3kPZS, as a partial pheromone that primarily induces upstream attraction, is unable to compete with the natural sex pheromone released by free-ranging males? For example, in experiments conducted in controlled stream environments, search time of ovulated females around 3kPZS-baited traps decreased substantially when caged spermiating males were placed upstream of a 3kPZS-baited trap (Luehring et al 2011). Therefore, an outstanding knowledge gap is whether the full blend of sex pheromone components could produce greater gains in trap catch relative to 3kPZS alone in free-ranging populations.…”

Matching tools to management goals

“…These include pheromones (attractants) and repellents. For example, pheromones emitted by male sea lampreys (Petromyzon marinus L.) are being tested to attract females to traps or streams of low ecological value (Luehring et al, 2011). Broadcast application of insect sex pheromones to reduce mating by interfering with normal mate attraction (called "mating disruption") is used in orchards and agricultural areas to reduce attack by pests such as the codling moth (Cydia pomonella L.) (Witzgall et al, 2008), and this approach can work in natural ecosystems to control or contain some invasive species, such as gypsy moth (Sharov et al, 2002;Brockerhoff et al, 2010).…”