complex calling song, Teleogryllus oceanicus (Orthoptera: Gryllidae)
Sean E. Walker and William H. Cade
Can. J. Zool./Rev. Can. Zool. 81(8): 1414-1420 (2003)
Abstract: We examined the effects of temperature and age on calling song in
the field cricket Teleogryllus oceanicus. Teleogryllus oceanicus has a
complex calling song made up of two different kinds of chirp, long and
short. The long chirp is made up of three to eight single pulses of sound
and the short chirp consists of several paired pulses. The properties of T.
oceanicus calling song did not vary with age, but almost every property of
the song varied with temperature. Pulse duration, interpulse interval, and
pulse rate in both the long and the short chirp varied with temperature. The
number of pulses in the long chirp, number of chirps in the short chirp,
chirp rate in the short chirp, duration of the long chirp, carrier frequency
of both the short and long chirps, and total song duration were also
affected by temperature. The duration of the short chirp and the degree of
frequency modulation were the only characteristics that did not vary with
temperature. Temperature does not affect the properties of the long and
short chirps in the same manner. The long chirp decreases in duration with
temperature and has fewer pulses, while the short chirp stays the same in
duration and contains a higher number of chirps. These data demonstrate that
temperature influences calling-song parameters in a field cricket with a
complex calling song.
Endothermy and chorusing behaviour in the African platypleurine cicada Pycna
semiclara (Germar, 1834) (Hemiptera: Cicadidae)
Martin H. Villet, Allen F. Sanborn, and Polly K. Phillips
Can. J. Zool./Rev. Can. Zool. 81(8): 1437-1444 (2003)
Abstract: Cicadas use acoustic signals to find mates and therefore offer a
phylogenetically independent opportunity to test the generality of ideas
about acoustic communication that were developed from studies of other
animals. Pycna semiclara (Germar, 1834) (Hemiptera: Cicadidae) is a
forest-dwelling platypleurine cicada that uses its calling song to form
choruses and attract mates. Additionally, P. semiclara produces an encounter
call that is involved in courtship and also in spacing males within
choruses. Males generally call from exposed trunks and branches within the
understory but clear of the undergrowth and fight with other males that call
within about 50 cm of them. Choruses sing sporadically throughout the day
but focus most of their calling activity into half-hour bouts at dawn and
dusk. Body size and ambient temperature had no significant effect on
spectral or temporal characteristics of the calling song. Body temperature
measurements indicate that P. semiclara thermoregulates endothermically,
with a body temperature of more than 22 °C above ambient temperature being
measured during calling activity at dusk. Such endothermy provides an
advantage to the cicadas by allowing them to call during crepuscular hours
when atmospheric conditions are most optimal for acoustic communication and
predation risks are minimal. Coincidentally, endogenously regulating body
temperature allows the temporal characteristics of the call to be unaffected
by ambient temperature changes.
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