Form and function of long-range vocalizations in a Neotropical fossorial rodent: the Anillaco Tuco-Tuco (Ctenomys sp.)

JUAN PABLO AMAYA; JUAN IGNACIO ARETA; VALENTINUZZI VERONICA; EMMANUEL ZUFIAURRE

PeerJ

PeerJ

Año: 2016

2167-8359

The underground environment poses particular communication challenges forsubterranean rodents. Some loud and low-pitched acoustic signals that can travellong distances are appropriate for long-range underground communicationand have been suggested to be territorial signals. Long-range vocalizations (LRVs)are important in long-distance communication in Ctenomys tuco-tucos. Wecharacterized the LRV of the Anillaco Tuco-Tuco (Ctenomys sp.) using recordingsfrom free-living individuals and described the behavioral context in whichthis vocalization was produced during laboratory staged encounters betweenindividuals of both sexes. Long-range calls of Anillaco tuco-tucos are lowfrequency,broad-band, loud, and long sounds composed by the repetition of twosyllable types: series (formed by notes and soft-notes) and individual notes. Allvocalizations were initiated with series, but not all had individual notes. Maleswere heavier than females and gave significantly lower-pitched vocalizations,but acoustic features were independent of body mass in males. The pronouncedvariation among individuals in the arrangement and number of syllables andthe existence of three types of series (dyads, triads, and tetrads), created adiverse collection of syntactic patterns in vocalizations that would provide theopportunity to encode multiple types of information. The existence of complexsyntactic patterns and the description of soft-notes represent new aspects of thevocal communication of Ctenomys. Long-distance vocalizations by AnillacoTuco-Tucos appear to be territorial signals used mostly in male-male interactions.First, emission of LRVs resulted in de-escalation or space-keeping in male-maleand male-female encounters in laboratory experiments. Second, thesevocalizations were produced most frequently (in the field and in the lab) by malesin our study population. Third, males produced LRVs with greater frequencyduring male-male encounters compared to male-female encounters. Finally,males appear to have larger home ranges that were more spatially segregatedthan those of females, suggesting that males may have greater need for long-distance signals that advertise their presence. Due to their apparent rarity,the function and acoustic features of LRV in female tuco-tucos remaininadequately known.