(names in bold are part of our Koala Ecology Group at UQ)
Bill in the field. Photo by Malcolm Ludgate
ABSTRACT (a summary of our study)
Acoustic communication mediates sociality in a variety of animals. One of the more ubiquitous vocal signals to have evolved is the sexual advertisement
call of males. Koala (Phascolarctos cinereus) males emit a sonorous bellow call during the breeding season, but no detailed studies of the calling context appear to have been published.
We used a novel remote sound detection network to monitor koala bellowing, whilst simultaneously collecting koala behavioral data using collar-mounted GPS units. Our approach enabled us to examine fine scale temporal variation in vocalization and spatial movements of free ranging koalas without direct 26 behavioral observations.
Bellow occurrence was susceptible to weather conditions, with fewer calls occurring when wind speed and temperatures were high. The number of bellow vocalizations recorded during an annual period mirrored breeding activity, with nearly all male bellows recorded during peak mating season. The distance traveled by koalas and the occurrence of koala bellows both peaked around midnight, but only female travel distance during the breeding season was temporally correlated with bellow occurrence.
We conclude that environmental factors might trigger male bellowing to launch the breeding season, and that these male vocal signals function more to attract females than to repel males. Female mate selection is probably an important component of male reproductive success in koalas, which is partly mediated by male bellow characteristics.
Written and transcribed by Amanda Niehaus, PhD
Written and transcribed by Amanda Niehaus, PhD
