Table 1.
Descriptions of behaviors that were scored.
Fig 1.
Representative spectrograms of nine call types of vocalizations.
Fig 2.
Latency of aggressive behavior and normalized duration of aggressive behavior of gerbil groups during resident-intruder tests.
(A) latency of aggressive behavior in VM-VM, EM-VM, VF-VF, and MF-VF pairs. Thick horizontal bars represent medians. (B) normalized duration of aggressive behavior in VM-VM, EM-VM, VF-VF, and MF-VF pairs. Thick horizontal bars represent medians. (●, virgin male; ▲, experienced male; ○, virgin female; △, multiparous female). N.S.: Not significant, ** represents p < 0.01.
Fig 3.
Relation between latencies of aggressive behavior and durations of aggressive behavior.
Latencies of aggressive behavior and durations of aggressive behavior were negatively correlated (●, virgin male; ▲, experienced male; ○, virgin female; △, multiparous female; rs = -0.669; p < 0.001).
Fig 4.
Vocalizations of gerbils during resident-intruder tests.
(A) Maximum fundamental frequency and duration of each vocalization. High-frequency groups are represented by bluish symbols and low-frequency groups are represented by reddish symbols. (B) Percentages of each call type emitted during the resident-intruder test are shown.
Table 2.
Spectro-temporal features of nine call types.
Fig 5.
Numbers of two call types by during resident-intruder pairs.
(A) Numbers of high-frequency calls per minute by pair-tests. VM-VM pairs emitted high-frequency calls much more than MF-VF pairs. (B) Numbers of low-frequency calls per minute by pair-tests. MF-VF pairs emitted low-frequency calls much more than the other pairs. (C) There is a negative correlation between the numbers of high-frequency calls and that of low-frequency calls (rs = -0.413; p = 0.036). Each symbol represents calls from a single test (●, virgin male; ▲, experienced male; ○, virgin female; △, multiparous female). * represents p < 0.05. *** represents p < 0.001.
Fig 6.
Relation between two types of calls and each behavior.
(A) Representative ethograms of each pair-test during resident-intruder tests. Ethograms for VM-VM, EM-VM, VF-VF, and MF-VF pairs were aligned from top to bottom. Bluish colors represent non-agonistic behaviors and reddish colors represent agonistic behaviors. Blue circles and red circles indicate >24.6 kHz calls and 24.6≤ kHz calls respectively. Red arrows indicate the timing when the resident initiated the first aggressive behavior. MF-VF pairs exhibited different patterns of vocalizations and behaviors. (B) The ratio of behaviors at the timing each call emitted. At the timing of high-frequency calls, agonistic interactions were rarely observed, contrary, at the timing of low-frequency calls, agonistic interactions were dominant. *** represents p < 0.001.
Fig 7.
Relationship between two types of calls and aggressive behaviors.
(A) Distributions of latency of aggressive behavior and rate of high-frequency vocalizations. (B) Distributions of latency of aggressive behavior and rate of low-frequency vocalizations. (C) Distributions of duration of aggressive behavior and rate of high-frequency vocalizations. (D) Distributions of duration of aggressive behavior and rate of low-frequency vocalizations. Each symbol represents vocalizations from a single test (●, virgin male; ▲, experienced male; ○, virgin female; △, multiparous female). * represents p < 0.05. ** represents p < 0.01.