Daily variation and repeatability of advertisement calls in an austral temperate forest frog under controlled conditions

Estimating repeatability allows a first approximation that may indicate a
potential response to selection of sexual traits. Acoustic sexual signals
comprise spectral and temporal variables, where the former generally have
lower intra-individual variation and higher repeatability values. Studies
of repeatability in anurans have been conducted mainly in natural
conditions, but the stability of laboratory settings allows extended
recording intervals, favoring measurement accuracy. We conducted a study
of variation and repeatability of the calls of males of Batrachyla
taeniata, a frog from the South American temperate forest to evaluate
under homogeneous environmental and social conditions: i) the extent of
variation in acoustic properties of calls within and among days, ii) the
extent of temporal variation in the repeatability of call properties, and
iii) differences in repeatability among call variables. Variation of
acoustic properties differed within and across days of recording, call
rate generally increased within and throughout days, suggesting
sensitization processes. Call duration decreased during these time spans,
yielding constant calling effort. In contrast, the dominant frequency
decreased within days but increased across days. Overall repeatability
differs significantly among variables: dominant frequency, call rate and
call duration having the highest, intermediate and lowest values,
respectively. The high repeatability of call rate relative to call
duration contrasts with an opposing general tendency in previous studies
in anurans. The repeatability of the three variables analyzed increases
within days and the repeatability of call rate also increases throughout
days, highlighting the relevance of this variable for individual identity
over different time ranges. The procedures were in accordance with
national laws of animal welfare and were approved by the Comité
institucional de cuidado y uso de animales (CICUA, Protocolo UNI
21014-MED-UCH). This dataset contains the acoustic variables analyzed in
the study. Specifically, the file “Data_DF_DUR.csv” includes 5 columns
corresponding to: ID of individuals, day, block, snout-vent length,
dominant frequency (Hz), duration (s). The file “Data_nCalls.csv” includes
4 columns corresponding to: ID of individuals, day, block, snout-vent
length, number of calls produced within 10 min. In addition, the R script
including the analyses and figures is provided.