First published online January 27, 2004
Journal of Experimental Biology 207, 803-811 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.00840
Female reply strategies in a duetting Australian bushcricket, Caedicia sp. (Phaneropterinae: Tettigoniidae: Orthoptera)
Winston J. Bailey* and
Thomas J. Hammond
School of Animal Biology, University of Western Australia, Nedlands,
WA 6009, Australia

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Fig. 1. (A) The male-female duet showing a male natural call (above) with a female
three-click reply (below). (B) Synthesised call of 19 `short' syllables
forming part B and 9 `long' syllables of part C. All traces share the 200 ms
time marker.
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Fig. 2. The response of females to model calls based on varying the number of
syllables in parts A and B (see Table
1), expressed as the sum of ranks of mean female clicks (see
Materials and methods). (A) Reply of female to part B containing 9, 18 and 30
syllables with part C constant, measured as rank sum of mean female clicks.
(B) The same measure to varying syllable number in part C with B held
constant.
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Fig. 3. Effect of presentation order on reply number (N=7). Each symbol
represents the mean value (N=24) from each female with each
presentation. While individual females were consistent in the number of their
replies, all females reduced the number of replies during the course of the
experiment (see text).
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Fig. 4. (A) Timing of one female's reply (animal no. 50) from the start of the male
call (zero). As the female increases the number of clicks the entire reply
remains within a distinct window between 800-1800 ms. The symbols and
associated legend indicate the timing of the first (diamond) to eighth click
(horizontal mark) of each set of clicks while the horizontal line indicates
the end of part C of the male call. (B) Timing of the first and last clicks of
seven females from the start of the male call; the open circles without error
bars represent data from one female only. The end of part C of the male call
is shown as a solid horizontal line while the end of part B is a broken line.
Values are means ± S.D.
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Fig. 5. Mean interval (± S.D., N=7) between successive
clicks decreases as the number of replies increases from 2 to 11. Replies 8-11
are from one female.
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Fig. 6. (A-D) Timing of the first click of the female reply with changing duration
of part C. y-axis values are from the start of part C while the
diagonal line represents the timing of the end of the song. As females
increase the number of clicks (from 1 to 4 clicks) and the duration of part C
increases the first click is more inclined to fall within the male call -
compare upper left to lower right in each panel.
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Fig. 7. Long and short reply strategies of female Caedicia (traces 2 and
3) to a male call (trace 1) consisting of two parts B and C. Females producing
a reply of six clicks have a low threshold at Y (high motivation), rising
after recognising elements of part C of the male call (at X). These females
call at the start of the species' specific reply window (shaded). Females with
high threshold (low motivation) fail to call at the conclusion of part C and,
following a brief silent interval, produce 1 or 2 clicks (at Z), which are
timed from the conclusion of the call. Note that the click rate of trace 3 is
faster than the rate for trace 2.
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© The Company of Biologists Ltd 2004