First published online October 10, 2003
Seismic signals in a courting male jumping spider (Araneae: Salticidae)
Damian O. Elias1,*,
Andrew C. Mason2,
Wayne P. Maddison3 and
Ronald R. Hoy1
1 Department of Neurobiology and Behavior,
Cornell University, Seeley G. Mudd Hall, Ithaca, NY 14853, USA,2
Division of Life Sciences, University of Toronto
at Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M16 1A4 and3
Department of Ecology and Evolutionary Biology,
University of Arizona, Tucson, AZ 85721, USA
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Fig. 3. Effects of male abdominal immobilization on power spectra of different
seismic signals. (A) Buzz signal; (B) scrape signal; (C) thump signal. Panels
i-iii represent mean power spectra for one individual during the control,
experimental and recovery treatments, respectively. Experimental treatment
consisted of waxing the cephalothorax to the abdomen, rendering body segments
immovable relative to each other. Recovery treatment consisted of removing the
wax from the animal.
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Fig. 5. Effects of preventing male abdominal and cephalothorax contact on the power
spectra of different seismic signals. (A) Buzz signal; (B) scrape signal; (C)
thump signal. Panels i-iii represent mean power spectra for one individual
during the control, experimental and recovery treatments, respectively.
Experimental treatment consisted of waxing a piece of flexible foil to the
cephalothorax and placing one end of the foil between the cephalothorax and
abdomen. Recovery treatment consisted of removing the foil from between the
cephalothorax and abdomen.
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Fig. 1. Seismic signals of courting male jumping spiders. (A) Sonogram of a seismic
signal. (B) Oscillogram of seismic signals. Courtship can be divided into four
distinct phases, with seismic signals occurring in phases 2-4. (C) Detail of
oscillogram marked by the box in B. All three types of seismic signals can be
observed: thumps [Th (red)], buzzes [Bz (green)] and scrapes [Sc (blue)].
Individual scrapes occur in groups consisting of multiple repeated scrapes [Sc
G (yellow)]. Recordings made using a laser Doppler vibrometer.
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Fig. 2. Types of seismic signals. Top panels (i) show body positions, with numbers
(1-5) illustrating movements of the forelegs and abdomen. Middle panels show
(ii) the position of one of the forelegs (mm above the substrate) and (iii)
the oscillograms of the seismic signals. Bottom panels (iv) show the frequency
characteristics of the seismic signals. Panels ii-iv are shown in the same
time scale, with numbers (1-5) corresponding to the body movements illustrated
in panel i. (A) Thump signal. Front legs come down (1-2), contact the
substrate and quickly move back up (2-3). Shortly afterwards the abdomen is
pulled back and released, and the abdomen `rings' at 58.3 Hz (4-5). Thumps are
broadband signals with peak frequencies at 203 Hz and 1203 Hz. Production of
signal corresponds with the percussive contact of the front legs against the
substrate (1-2) and movements of the abdomen (4-5). (B) Scrape signal. Abdomen
moves up (1-2) and shortly afterwards the front legs come down (2-3). Scrapes
occur in groups with a frequency of 5.7 Hz. Scrapes are broadband signals with
peak frequencies at 230 Hz and 550 Hz. Production of seismic signal
corresponds to movements of the abdomen. (C) Buzz signal. Front legs come down
(1-2) as the abdomen oscillates at 65 Hz (1-2). This signal has a fundamental
frequency at 65 Hz with several harmonic frequencies (130 Hz, 195 Hz and 260
Hz). Production of seismic signal corresponds with movements of the front legs
and abdomen.
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Fig. 4. Effects of male abdominal immobilization on (A) thump, (B) scrape and (C)
buzz seismic signals. Within individuals, peak intensities were normalized to
the maximum intensity produced for all of the signal components. Normalized
intensities were then averaged, and the relative dB difference between the
treatments calculated. Graphs show relative dB difference between the
treatments (control, experimental treatment and recovery) of all the
individuals tested ± S.D. (N=5). Experimental
treatments attenuated peak frequencies of all signals significantly
(**P<0.001; Tukey post-hoc test with
Bonferonni corrections). No significant differences were observed between
control and recovery treatments.
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Fig. 6. Effects of preventing male abdominal and cephalothorax contact on (A)
thump, (B) scrape and (C) buzz seismic signals. Within individuals, peak
intensities were normalized to the maximum intensity produced for all of the
signal components. Normalized intensities were then averaged, and the relative
dB difference between the treatments calculated. Graphs show relative dB
difference between the treatments (control, experimental treatment and
recovery) of all the individuals tested ± S.D.
(N=5). Experimental treatments attenuated peak frequencies of scrape
and high-frequency (>500 Hz) ranges of thumps significantly
(*P<0.05; Tukey post-hoc test with Bonferonni
corrections). No significant differences were observed for buzz and low
(<500 Hz)-frequency ranges of thumps. No significant differences were
observed between control and recovery treatments.
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Fig. 7. Scanning electron micrograph (SEM) of cephalothorax and abdomen junction on
(A) female and (B) male H. dossenus. (i) SEM of the posterior end of
the head; (ii) SEM of the anterior end of the abdomen. F represents the ridged
file found on male H. dossenus. S shows the location of the scrapers
on the male.
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© The Company of Biologists Ltd 2003
