First published online February 15, 2008
Journal of Experimental Biology 211, 757-765 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.012773
Finding females: pheromone-guided reproductive tracking behavior by male Nereis succinea in the marine environment
Jeffrey L. Ram1,2,*,
Xubo Fei3,
S. Michelle Danaher2,
Shiyong Lu3,
Thomas Breithaupt2 and
Jörg D. Hardege2
1 Department of Physiology, Wayne State University, Detroit, MI 48201, USA
2 Department of Biological Sciences, University of Hull, Hull HU6 7RX, UK
3 Department of Computer Science, Wayne State University, Detroit, MI 48202,
USA
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Fig. 1. Spontaneous swimming and responses of male N. succinea to low
concentrations of CSSG. Points show animal positions at 0.2 s intervals. (A)
No CSSG present. (B) CSSG present in a remote part of the tank (yellow strip).
The image shows three different paths swum down the left side of the internal
apex and one `cross-tank' path. (C) Lack of response to low concentration of
CSSG. The trail was created with 0.2 ml of 10–8 mol
l–1 CSSG and therefore has an estimated trail concentration
of <10–9 mol l–1. (D) Responses to a
trail made with 10–7 mol l–1 CSSG (estimated
trail concentration of <10–8 mol l–1
CSSG).
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Fig. 2. Weaving pattern of N. succinea upon encountering a trail of
glutathione at an oblique angle. The concentration of glutathione in the
syringe was 10–5 mol l–1, yielding a trail
(gray streak) concentration somewhat less than 10–6 mol
l–1. (A–F) Successive images of the path swum by the
animal (indicated by the broken line in F). The total time between images A
and F was 3 s. The 10 cm calibration applies to all parts.
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Fig. 3. Trail-following swimming pattern of N. succinea upon encountering
a trail of CSSG at an oblique angle. (A) Two CSSG trails were present, as
outlined. The concentration of CSSG in the syringe was 10–7
mol l–1, yielding a trail concentration
<10–8 mol l–1. (A–D) Successive
images of the path swum by the animal (indicated by the broken line in D). The
10 cm calibration in A applies to all parts.
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Fig. 4. Response of a male N. succinea to a moderate concentration of
CSSG. Images show the swim track, plotted every 0.2 s. The concentration of
CSSG in the syringe was 10–6 mol l–1,
yielding a trail concentration <10–7 mol
l–1. The drawings show the position of the original CSSG
trail and do not show the dispersion of the chemical as the worm swims through
it (to observe dispersion of the trail, see Movie 1 in the supplementary
material). Swim tracks are sequential recordings of 5 s (A–E) and 4 s
(F). (A) Typical `wall-swimming' behavior prior to encountering CSSG. (B,C)
CSSG stimulates circling behavior. (D–F) Larger circles result as the
worm encounters more dilute dispersed CSSG.
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Fig. 5. Dose–response and arousal time-courses used for simulation modeling
of male N. succinea swimming responses to CSSG. (A)
Dose–response relationship for speed arousal. The equation used was
speed=50+(180–50)/{1+10^[(–7–log[CSSG])*0.6]}.
(B) Time-course of arousal and duration of the response, as a percentage of
the maximum response to the encountered CSSG stimulus. The equation used was
%=130*[1–EXP(–time)]^3*EXP(–time/20).
(C) Dose–response relationship for turning arousal. The equation used
was angle
s–1=(750)/{1+10^[(–7–log[CSSG])*0.6]}.
(D) Time course of arousal and duration of the turning response, as a
percentage of the maximum response to the encountered CSSG stimulus. The
equation used was %=
100*[1–EXP(–time/0.05)]^3–[1–EXP(–time/0.05)]*[1–EXP(–time/0.5)]^25.
The preceding formulae are written with Excel spreadsheet functions and
operators, where EXP() means e raised to the power in the parentheses, ^ means
exponential and * means multiplication.
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Fig. 6. Simulated behavior of male N. succinea in response to various
concentrations of CSSG. The direction and starting point of the worm in the
simulation is shown by the yellow arrow in each illustration; the trajectory
of the worm is indicated by the narrow black line; the simulated final
position of the worm when the simulation was terminated is shown by the short
black line; and the dispersion of pheromone by the simulated swimming of the
worm through it is shown by the spread of the blue color of the initial line
of pheromone (initially approximately 7 mm wide). Concentrations of pheromone
in the simulated `trail' initially were (A) 0 (control, no pheromone),
(B–D) log[CSSG]=–8.5 (i.e. 3.16x10–9 mol
l–1), (E) log[CSSG]=–8.0 (i.e. 10–8
mol l–1), and (F) log[CSSG]=–8.5 (i.e.
3.16x10–8 mol l–1). The 10 cm
calibration applies to all parts.
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© The Company of Biologists Ltd 2008
20 cm to the right of the closest
point of the trail from the simulated male. The male starts 5 cm from the
trail, so that the female is at an angle of