Kate Arnold, Yvonne Pohlner and Klaus Zuberbühler (2008): A forest monkey?s
alarm call series to predator models. Behav. Ecol. Sociobiol. 62(4),
549-559.
Abstract: Some non-human primates produce acoustically distinct alarm calls
to different predators, such as eagles or leopards. Recipients respond to
these calls as if they have seen the actual predator, which has led to the
notion of functionally referential alarm calls. However, in a previous study
with free-ranging putty-nosed monkeys (Cercopithecus nictitans martini), we
demonstrated that callers produced two acoustically distinct alarm calls to
eagle shrieks and leopard growls, but both alarm calls were given to both
predators. We can think of two basic explanations for this surprising
result, a methodological and theoretical one. Firstly, acoustic predator
models may not always be suitable to test alarm call behaviour in primates,
sometimes causing uncharacteristic behaviour. Secondly, referential alarm
calling may not be a universal feature of primate alarm call systems.
Considering the methodological and theoretical importance of these
possibilities, we conducted a follow-up study using life-sized leopard,
eagle, and human models on the same population and compared the resulting
vocal responses to those given to acoustic predator models. We compared the
alarm call series given to each of these predator model types and found a
considerable degree of consistency suggesting that the mode of presentation
did not affect anti-predator calling strategies. However, evidence for
audience effects on calling behaviour was inconclusive. While it appears
that predator class is reliably encoded by different call series types
irrespective of the mode of presentation, observations of these same call
series given in non-predatory contexts indicate that predator class is
unlikely to be the relevant organising principle underlying the
alarm-calling behaviour in this species. We conclude by offering an
alternative, non-referential, account of the alarm-calling system exhibited
by this species.
URL: http://www.springerlink.com/content/256k473g26168216/
For reprints please contact Kate Arnold (Email:
Gerlind U. C. Lehmann and Arne W. Lehmann (2008): Bushcricket song as a clue
for spermatophore size? Behav. Ecol. Sociobiol. 62(4), 569-578.
Abstract: Bushcricket males of Poecilimon zimmeri transfer large and
protein-rich spermatophores during mating, which females directly ingest.
There is correlational evidence that heavier males transfer larger nuptial
gifts. In no-choice mating trials, females mated randomly with respect to
male?s body weight. In contrast, in two-choice mating trials, female
bushcrickets exhibit clear choice for the heavier male. This heavier male
advantage was also found in pre-mating choice during phonotaxis. With
manipulated mute males, females mated at random with regard to body weight
of the competitors. The number of physical encounters between a female and
males was low in all tests with a single male (no choice) and greater in
choice-tests with two competing males. The latencies to mate also differed
significantly between treatments. The time mating pairs spent in precopula
was short in experiments where the males could hear rivals and significantly
longer in all other tests using either a single male or mute males. Thus,
acoustic signalling in male bushcrickets seems to signal male body weight. A
preference for heavier males may reflect a female?s preference for a larger
spermatophore and therefore a greater direct benefit.
URL: http://www.springerlink.com/content/r8612pmw5147rn75/
For reprints please contact Gerlind U. C. Lehmann (Email:
Kind regards
Sonja Amoser
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