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Felipe A. L. Contrera and James C. Nieh (2007): The effect of ambient
temperature on forager sound production and thoracic temperature in the
stingless bee, Melipona panamica. Behav. Ecol. Sociobiol., 61(6), 887-897.
Abstract: Foragers of the stingless bees genus Melipona may produce
intranidal sounds that are correlated with food location and quality. In
this study, we provide the first detailed analysis of pulsed sounds produced
by Melipona panamica foragers while feeding on a carbohydrate food source.
We trained foragers to a 2.5-M sucrose feeder under normal, ambient
temperature (23?33°C) and lower temperature (11?25°C) conditions. We
recorded forager sounds under both conditions and tested the effect of
temperature of the thorax, feeder plate, and air on sound temporal
characteristics. Forager energetic expenditure and the number of pulses per
visit were significantly higher in the cold condition than in the normal
condition. Foragers spent a longer time at the feeder under the cold
condition than during the normal condition. Interpulse durations were
significantly shorter in the cold condition than in the normal condition and
became progressively and significantly shorter at the end of each
performance. Thus, pulse production increased before departure. Foragers
increased their thoracic temperatures above ambient at all experimental air
temperatures. Under chilled conditions, foragers had a significantly greater
difference between thorax temperature and ambient air temperature than under
normal conditions. Foragers must achieve a minimum flight muscle temperature
before take-off, and thus forager sounds may be linked to muscle warm-up.
Roman M. Wittig, Catherine Crockford, Robert M. Seyfarth and Dorothy L.
Cheney (2007): Vocal alliances in Chacma baboons (Papio hamadryas ursinus).
Behav. Ecol. Sociobiol., 61(6), 899-909.
Abstract: Theory predicts that females in species with matrilineal dominance
hierarchies should use nepotistic support systems to maintain their family?s
rank. Female Old World monkeys, however, form alliances against other
females at surprisingly low rates. Nonetheless, in many species, females
utter threat vocalizations when observing others? disputes, suggesting that
these vocalizations may function as ?vocal alliances?. We describe a
playback experiment testing the efficacy of vocal alliances in free-ranging
female baboons. Subjects were played the same female?s threat-grunts under
three separate conditions: after being threatened by the signaller?s close
relative to mimic kin support, after being threatened by a female maternally
unrelated to the signaller to mimic non-kin support, and after a friendly
interaction with the signaller?s close relative as a control. Subjects
responded more strongly to the playback and avoided the signaller and her
matrilineal relatives for a longer period of time in kin support trials than
in either non-kin support or no aggression trials. In contrast, there was no
difference in subjects? behaviour between non-kin support and no aggression
trials. These results corroborate observational data showing that vocal
support occurs at a higher rate than physical support in female baboons, and
that kin are more likely to provide vocal support than non-kin. We conclude
that vocal support plays a similar role as physical support in the alliances
of female baboons.
Mark A. Bee (2007): Selective phonotaxis by male wood frogs (Rana sylvatica)
to the sound of a chorus. Behav. Ecol. Sociobiol., 61(6), 955-966.
Abstract: Frogs and toads commonly form large choruses around suitable
breeding habitat during the mating season. Although often regarded as a
constraint on the acoustic behavior of signalers and receivers, the sounds
of a chorus could also serve as an acoustic beacon that allows some frogs to
locate the breeding aggregation. Attraction to chorus sounds might be
particularly important for explosively breeding frogs. In these species,
which often mate just one or a few days during the year, the timing and
location of breeding aggregations can be unpredictable because their
formation often depends on local climatic factors, such as rainfall or a
change in temperature. I used laboratory playback experiments to test the
hypothesis that male wood frogs (Rana sylvatica), an explosively breeding
frog, exhibit positive phonotaxis toward the sound of a conspecific chorus.
Males were released at the center of a rectangular arena with a speaker
positioned in each corner facing toward the release point. In a
single-stimulus experiment, more males approached a speaker broadcasting a
conspecific chorus than the three silent speakers in the arena. In a
two-stimulus experiment, more males approached a speaker broadcasting a
conspecific chorus compared to the two silent speakers or a fourth speaker
simultaneously broadcasting the spectrally overlapping sound of a
heterospecific (R. septentrionalis) chorus. These results are consistent
with the hypothesis that male wood frogs could use the sound of a chorus as
a beacon to locate a short-lived breeding aggregation.
University of Vienna, Dept. of Behavioural Biology
Doctoral Student, Research Associate
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