Field study suggests that sex determination in sea lamprey is directly influenced by larval growth rate
Citation
Johnson NS, Swink WD,
Brenden TO. 2017 Field study suggests that sex
determination in sea lamprey is directly
influenced by larval growth rate. Proc. R. Soc. B
284: 20170262.
http://dx.doi.org/10.1098/rspb.2017.0262
Summary
Sex determination mechanisms in fishes lie along a genetic-environmental continuum and thereby offer opportunities to understand how physiology and environment interact to determine sex. Mechanisms and ecological consequences of sex determination in fishes are primarily garnered from teleosts, with little investigation into basal fishes. We tagged and released larval sea lamprey (Petromyzon marinus) into unproductive lake and productive stream environments. Sex ratios produced from these environments were quantified by recapturing tagged individuals as adults. Sex ratios from unproductive and productive environments were initially similar. However, sex ratios soon diverged, with unproductive environments becoming increasingly male-skewed [...]
Summary
Sex determination mechanisms in fishes lie along a genetic-environmental
continuum and thereby offer opportunities to understand how physiology
and environment interact to determine sex. Mechanisms and ecological
consequences of sex determination in fishes are primarily garnered from
teleosts, with little investigation into basal fishes. We tagged and released
larval sea lamprey (Petromyzon marinus) into unproductive lake and
productive stream environments. Sex ratios produced from these environments
were quantified by recapturing tagged individuals as adults. Sex
ratios from unproductive and productive environments were initially similar.
However, sex ratios soon diverged, with unproductive environments
becoming increasingly male-skewed and productive environments becoming
less male-skewed with time. We hypothesize that slower growth in
unproductive environments contributed to the sex ratio differences by
directly influencing sex determination. To the best of our knowledge,
this is the first study suggesting that growth rate in a fish species directly
influences sex determination; other studies have suggested that the environmental
variables to which sex determination is sensitive (e.g. density,
temperature) act as cues for favourable or unfavourable growth conditions.
Understanding mechanisms of sex determination in lampreys may provide
unique insight into the underlying principles of sex determination in other
vertebrates and provide innovative approaches for their management
where valued and invasive.
