Ovaska KE, Caldbeck J
Renewable Resources Consulting Services Ltd, Sidney, B.C.
Anim Behav. 1997 Jul;54(1):181-8. doi: 10.1006/anbe.1996.0414.
The vocal repertoire of male Eleutherodactylus and the communicative significance of two calls (trill and courtship call) were investigated under natural conditions on the British Virgin Islands. Interspersed with two-note advertisement calls, males uttered trill calls, which typically consisted of an introductory note followed by five to 13 rapidly repeated notes. The introductory note and the repeated notes were within the range of the dominant frequencies of the first and second note of the advertisement call, respectively, but their mean frequencies were 5-8% higher. The temporal and spectral characteristics of the trill and advertisement calls were similar on three islands (Tortola, Virgin Gorda, Guana), except that the number of repeated notes in the trill was higher on Guana. Body size and air temperature had no detectable effects on the call characteristics. In response to experimental playback of trill calls (either synthesized or constructed from actual calls), males produced more trills in the period following the stimulus than during the baseline. During the playback itself, five or 22 males produced an unusually high number of trills that alternated with the stimulus trills. These responses suggest that the trill is an aggressive call used in the defence of a calling territory. In response to the playback of courtship calls (multi-note calls that males uttered only in the presence of a female and that differed from the trill call mainly in the dominant frequency of the repeated notes), 11 of 28 males left their perch sites and nine approached the speaker. In contrast, males never left their perches during the baseline or the trill stimulus. These responses suggest that males may exploit the courtship calls of rivals to obtain mates through interference.
在英属维尔京群岛的自然条件下，对雄性 Eleutherodactylus 的鸣声 repertoire 以及两种叫声（颤音和求偶叫声）的交流意义进行了研究。雄性发出的颤音夹杂在两音符的广告叫声之间，通常由一个起始音符后跟五到十三个快速重复的音符组成。起始音符和重复音符分别在广告叫声的第一个和第二个音符的主频范围内，但它们的平均频率高 5 - 8%。在托尔托拉岛、维尔京戈尔达岛、瓜纳岛这三个岛屿上，颤音和广告叫声的时间和频谱特征相似，只是瓜纳岛上颤音的重复音符数量更多。体型和气温对叫声特征没有可检测到的影响。对颤音叫声（合成的或由实际叫声构建的）进行实验回放时，雄性在刺激后的时间段内比基线期间发出更多颤音。在回放过程中，有五只或二十二只雄性发出了异常多的颤音，与刺激颤音交替出现。这些反应表明颤音是一种用于保卫鸣叫领地的攻击性叫声。对求偶叫声（雄性仅在有雌性在场时发出的多音符叫声，与颤音叫声的主要区别在于重复音符的主频）进行回放时，28 只雄性中有 11 只离开了栖息位点，9 只靠近了扬声器。相比之下，在基线或颤音刺激期间，雄性从不离开它们的栖息处。这些反应表明雄性可能通过干扰利用竞争对手的求偶叫声来获取配偶。
