(Abstracts below)
Brumm, H & A Zollinger (2011) The evolution of the Lombard
effect: 100 years of psychoacoustic research. Behaviour 148:
1173-1198.
Krause, ET, M Honarmand & M Naguib (2011) Zebra finch nestlings
beg more under better nutritional conditions. Behaviour 148:
1239-1255.
Terleph, TA (2011) A comparison of prairie vole audible and
ultrasonic pup calls and attraction to them by adults of each sex.
Behaviour 148: 1275-1294.
Abstracts:
Brumm, H & A Zollinger (2011) The evolution of the Lombard
effect: 100 years of psychoacoustic research. Behaviour 148:
1173-1198.
On the occasion of the centenary of the discovery of the Lombard
effect, we review the literature on noise-dependent regulation of
vocal amplitude in humans and other animals. The article addresses
the scientific and the biological history of the Lombard effect:
first, it sketches the evolution of the study of the Lombard effect,
and second it reflects on the biological evolution of the effect
itself. By comparing the findings from anurans, birds and mammals,
we try to trace back the phylogenetic origins of this basic vocal
mechanism for acoustic communication in noise. The current evidence
suggests two alternative parsimonious hypotheses: either the Lombard
effect is the outcome of a convergent evolution in birds and mammals
or it may be a synapomorphy of all amniotes. If the latter is true,
then the Lombard effect would have evolved to maintain vocal
communication in the presence of noise more than 300 million years
ago.
Krause, ET, M Honarmand & M Naguib (2011) Zebra finch nestlings
beg more under better nutritional conditions. Behaviour 148:
1239-1255.
Providing parental care involves costs for the parents when
investing resources such as food and time to raise their offspring.
In many species, offspring communicate their need by begging signals
which often are linked to their physiological condition but also may
be affected by the expectation they may develop depending on
previous parental behaviour. To test whether or not offspring
begging is affected by the food quality to which parents have
access, we experimentally manipulated the early nutritional
conditions of zebra finch (Taeniopygia guttata) nestlings by
providing the parents with either a low or a high quality diet. We
expected that lower early nutritional conditions increase begging
behaviour resulting from a presumed higher nestling need. Yet, the
experiments revealed that broods of nestlings begged more intensely
when they were raised on a high compared to a low quality diet.
Nestlings raised under high quality food conditions may have a
higher begging intensity due to their higher need associated with a
fast growth trajectory. Likewise, lower begging intensity by
nestlings raised on low quality food might result from a general
delay in development, or nestlings adjusted their begging to
behavioural adjustments made by parents as a response to the
different diets. These findings highlight that begging signals can
be affected by a complex set of factors and expands the classical
view of signalling need. Begging call rates can increase with
offspring condition and with their expectations about the quality of
food that can be provided by the parents.
Terleph, TA (2011) A comparison of prairie vole audible and
ultrasonic pup calls and attraction to them by adults of each sex.
Behaviour 148: 1275-1294.
Rodent pups of many species emit both ultrasonic vocalizations
(USVs) and calls spanning into a lower frequency range, audible to
humans (AUDs), yet there has been little systematic comparison of
these different call types, or analyses of how they might differ in
signal function. Here the spectral and temporal characteristics of
USV and AUD pup calls are described for the prairie vole (Microtus
ochrogaster), a model used in studies of monogamous mating and
biparental care, and a species with an unusually large functional
and anatomical representation of auditory cortex. Findings provide a
detailed description of each call type, including changes to a
number of USV characteristics over pup development. Adult attraction
to the playback of these two call types was tested in groups that
differed in regards to sex and reproductive status. Separate groups
included virgins as well as paired animals of each sex, tested at
time points either prior to the birth of pups (associated with
either mid or late gestation), or at postpartum time points (parents
of 2-3 day olds and parents of 8-9 day olds). Adults were attracted
to both USVs and AUDs, but group differences were found only in the
attraction to USVs. Males were more attracted to USVs than females,
and there were interactions of sex and reproductive status. Results
suggest that pup vocal communication is quite sophisticated, and
that USVs and AUDs may have different communicative functions.
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