DOI: 10.5061/dryad.8931zcrvk
title: Data from: Male lake char release taurocholic acid as part of a mating pheromone

description: The evolutionary origins of sexual preferences for chemical signals remain
 poorly understood, due, in part, to scant information on the molecules
 involved. In the current study, we identified a male pheromone in lake
 char (Salvelinus namaycush) to evaluate the hypothesis that it exploits a
 nonsexual preference for juvenile odour. In anadromous char species, the
 odour of stream-resident juveniles guides migratory adults into spawning
 streams. Lake char are also attracted to juvenile odour but have lost the
 anadromous phenotype and spawn on nearshore reefs, where juvenile odour
 does not persist long enough to act as a cue for spawning site selection
 by adults.  Previous behavioural data raised the possibility that
 males release a pheromone that includes components of juvenile odour.
 Using metabolomics, we found that the most abundant molecule released by
 males was also released by juveniles but not females. Tandem mass
 spectrometry and nuclear magnetic resonance were used to identify the
 molecule as taurocholic acid (TCA), which was previously implicated as a
 component of juvenile odour. Additional chemical analyses revealed that
 males release TCA at high rates via their urine during the spawning
 season. Finally, picomolar concentrations of TCA attracted prespawning and
 spawning females but not males. Taken together, our results indicate male
 lake char release TCA, a mating pheromone, and support the hypothesis that
 the pheromone is a partial match of juvenile odour.
description: # Male lake char release taurocholic acid as part of a mimetic pheromone
 --- Data include: 1. metabolomics results comparing chemical features of
 male, female, juvenile, and control water samples, 2. concentrations of
 taurocholic acid in male and female urine and conditioned water, 3.
 concentrations of taurocholic acid in male-conditioned water during and
 outside of the spawning season, and 4. behavioral responses of
 pre-spawning and spawning male and female lake char to taurocholic acid in
 two two-channel flumes. ## Description of the data and file structure
 Metabolomics file: * Water samples were collected by holding one male or
 female lake char, or 3 juveniles in 150 L of Lake Huron water for four
 hours. * Peak1 through Peak5 are the relative magnitudes of the top five
 peaks found in male-conditioned water using high-resolution mass
 spectrometry. * TCA is the concentration (ng/mL) of taurocholic acid in
 these water samples * Juv.2 and Juv.3 are the weights and lengths of the
 2nd and 3rd juveniles sampled. Release route file: * Water samples were
 collected by holding one male or female lake char in 150 L of Lake Huron
 water for four hours. * Urine was collected via catheter one day after
 initial water samples were collected * water.TCA is the concentration of
 TCA (ng/mL) in water * urine.TCA is the concentration of TCA (ng/mL) in
 urine Release rate by season file: * Water samples were collected by
 holding one male in approximatly 563.4 L of Lake Huron water for 4 hours.
 Sampling was done during the spawning season (October) and outside of the
 spawning season (April) * Start.TCA is the concentration of TCA (ng/mL) in
 water at time-0 h * End.TCA is the concentration of TCA (ng/mL) in water
 at time-4 h Behavior * Behavioral responses of prespawning and spawning
 male and female lake char were tested in two two-channel flumes. Time
 (sec) spent in each of the two channels was recorded before and after
 appplication of 1 x10-12M TCA * im = prespawning male; if = prespawning
 female; mm = spawning male; mf = spawning female * id is individual id of
 fish * period is pre-odor application (pre) and post-odor application
 (post) * con.s is the time (sec) spent in the control channel * trt.s is
 the time (sec) spent in the treatment channel * trt.p is the proportion of
 time spent in the treatment channel ## Code/Software statistical analysis
 of the data were ran in R using the script "trout_script"