**ABSTRACT NOT FOR CITATION WITHOUT AUTHOR PERMISSION. The title, authors, and abstract for this completion report are provided below. For a copy of the full completion report, please contact the author via e-mail at liweim@msu.edu Questions? Contact the GLFC via email at slrp@glfc.org or via telephone at 734-662-3209.**
STRUCTURE
AND FUNCTION OF SEA LAMPREY PHEROMONE COMPONENTS (PHASE II)
1 Michigan
State University, Department of Fisheries & Wildlife, liweim@msu.edu,
like4@msu.edu, fissette@msu.edu
2 University
of Michigan, Graham Sustainability Institute, brantco@umich.edu
3Texas State University,
Department of Biology, mhuertas@txstate.edu
December 2018
ABSTRACT:
The complex pheromone communication
system employed by lamprey is essential for its life cycle, making
pheromones targets for sea lamprey control.
Our overarching objective was to characterize the structures and
functions of candidate pheromone components released by larvae and sexually
mature males. Several novel
tetrahydrofuran-diol lipids were isolated from larval washings and subsequently
tested on migratory adults. One
compound, (+)-PMA is the first compound tested that replicates larval washings
in biasing migratory adults into a stream channel. We isolated eight novel sulfated steroid
compounds from mature male washings; five were significantly attractive and one
significantly repulsive to ovulated females in a two-choice maze. However, these were never
tested using in-stream assays, so more detailed behavioral responses
were not characterized. Two additional
sulfated steroid compounds DkPES and PAMS-24 were shown to act as proximity pheromones that influence
female behavior near an odor source. Our
results also indicate PAMS-24 may act as a territorial pheromone for mature
males, but we are still evaluating this hypothesis. Multiple
advances were also made in our general understanding
of the pheromone communication network.
We identified females can differentiate a pheromone signal based on
sexual context, and that 3kPZS can outweigh temperature in influencing
migratory females to move upstream.
Additionally, there are multiple factors that influence pheromone
release by sexually mature males. Male
size, competition, and time of day all have impacts on 3kPZS release and
provide insights into evolutionary mechanisms that have shaped the signaling
system. Overall, we isolated 18
compounds; 16 were tested for olfactory potency using
electro-olfactogram recordings (EOGs), and 14 were
tested for behavioral responses using a two-choice maze or in-stream assays.