1. Movement of wild and laboratory-reared guppies
(Poecilia reticulata)Klemet-N’Guessan, S., Blondel L., Hendry A.
McGill University, Montreal, QC. Redpath Museum and Dept Of Biology.
INTRODUCTION
o Rheotaxis is the ability of fish to orientate to current1
o There is a relationship between flow speed and the rheotactic
behavior displayed2
o The guppy Poecilia reticulata, has been studied as a model
organism for life-history divergence between low and high
predation habitats3
o The Trinidadian guppy is a great opportunity to study movement
in water flow
HYPOTHESIS
We compare the movement of a wild-caught guppy population
and laboratory-reared guppy individuals that have never
experienced water current
o Wild-caught fish (WC) were randomly selected from high-
predation streams in three Trinidadian rivers: Aripo, Oropuche
and Turure (n=8)
o Laboratory-reared fish (LR) were randomly selected from
laboratory-breeding stocks (n=14)
o We used a circular flow tank (Figure 1) to assess the movement
of each individual. The tank was divided into three sections,
with the middle section further divided into four concentric
zones of different water flow (flow speed zones): High, Medium,
Low and Minimal, from the outermost to the innermost region
of the middle section of the tank, respectively
o We tested and videotaped each fish separately for a 5-minute
trial
o We used ImageJ to analyze the video frames and R Studio for
the statistical analyses4
RESULTS
Figure 3. Bar graph comparing the mean population velocity ± standard error
in each flow speed zone between the laboratory-reared (LR, white bars) and
wild-caught (WC, black bars) population
CONCLUSION
o Our results suggest that laboratory-reared and wild-caught
guppy populations do not differ in their general movement
patterns
o The differences observed in the mean velocity per zone could
be due to a difference in movement patterns when facing
currents. This suggests that the methodology we have
developed will be useful for comparing the rheotactic behavior
of different natural populations
METHODS
ACKNOWLEDGMENTS
AIM OF THE STUDY
Experience and/or adaptive plasticity will make the wild-caught
fish perform better as they have previously been in current.
Conversely:
◦ Laboratory-reared fish should display little or no station-keeping
behavior
◦ Laboratory-reared fish will try to avoid the flow by staying in the
lower-current boundary areas
REFERENCES
Figure 2. Total distance traveled by guppies from the laboratory-reared (LR)
and from the wild-caught (WC) populations. The dot represents an outlier, the
bars the lower and upper limits, and the box represents first and third
quartile value with the median
o The total distance traveled and the flow regime (i.e in each
video frame the fish was scored as being in one of the four flow
zone, and this score was then averaged) were highly positively
correlated (r = 0.64, P = 0.002). Guppies in faster water went
further
o There was no significant difference in the total distance traveled
between laboratory-reared and wild-caught populations
o Mean velocity per zone was significantly higher among the
laboratory-reared population than the wild-caught (F = 10.86, df
= 28, P<0.0001)
1Arnold, G. P. 1974. Rheotropism in fishes. Biol. Rev. Camb. Philos. Soc.
49:515–576.
2Jiang, Y., L. Torrance, C. L. Peichel, and D. I. Bolnick. (In press). Differences in
rheotactic responses contribute to divergent habitat use between parapatric
lake and stream threespine stickleback. Evolution.
3Magurran, A. E. 2005. Evolutionary ecology: the Trinidadian guppy.
4Rasband, W. 2012. ImageJ. U. S. Natl. Institutes Heal. Bethesda, Maryland,
USA 403 //imagej.nih.gov/ij/;
5R Development Core Team, R. 2011. R: A Language and Environment for
Statistical Computing. R Foundation for Statistical Computing.
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Meanvelocity(cm.s-1)
Flow speed zones
LR
WC
LR WC
Minimal Low Medium High
This work is the preliminary data for a larger study that will
incorporate predation level, parasitism, as well as the direction of
movement in order to directly assess the rheotactic behavior of
natural populations and compare different populations coming
from above and below waterfalls environments
FUTURE DIRECTIONS
Figure 1. Middle section of the circular flow tank
divided in four flow speed zones
I especially thank Caroline LeBlond, Krista Oke , and Sian Kou-Giesbrecht for
their help