Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, 151-742, Republic of Korea.
Department of Life Sciences and Division of EcoScience, Ewha Womans University, Seoul, 120-750, Republic of Korea.
Sci Rep. 2016 Sep 7;6:32569. doi: 10.1038/srep32569.
Interspecific competition occurs when one species using a resource limits the use of that resource by another species. A dominance relationship between the species competing over a resource may result in asymmetric competition. Here, we tested the hypothesis that two sympatric treefrog species, the endangered Hyla suweonensis and the abundant H. japonica, compete with each other over calling sites. We observed the locations of calling individuals of the two treefrog species in rice paddies and tested whether removing one species affected the calling locations of the other species. Individuals of the two species were spatially isolated within rice paddies, with H. japonica at the edges and H. suweonensis in the interior. Male H. suweonensis moved towards the edges of rice paddies when male H. japonica were removed from the area, whereas male H. japonica hardly moved when male H. suweonensis were removed. The results of both studies are consistent with asymmetric interspecific competition, in which the calling locations of H. suweonensis are affected by the calling activity of H. japonica. In addition, H. japonica were found "sitting" on the substrate during call production, whereas H. suweonensis were "holding" onto vegetation. The difference in calling posture may represent an adaptive response to asymmetric interspecific competition.
种间竞争发生在一种物种使用资源时限制了另一种物种对该资源的使用。在竞争资源的物种之间可能存在优势关系，从而导致不对称竞争。在这里，我们检验了这样一个假设，即两种同域分布的树蛙物种，濒危的沼蛙和丰富的日本林蛙，会争夺鸣叫地点。我们观察了这两种树蛙在稻田中的鸣叫个体的位置，并测试了移除一种物种是否会影响另一种物种的鸣叫位置。这两种物种的个体在稻田中是空间隔离的，日本林蛙在边缘，沼蛙在内侧。当雄性日本林蛙被从该区域移除时，雄性沼蛙会向稻田边缘移动，而当雄性沼蛙被移除时，雄性日本林蛙几乎不会移动。这两项研究的结果都与不对称的种间竞争一致，即沼蛙的鸣叫位置受到日本林蛙鸣叫活动的影响。此外，我们发现日本林蛙在鸣叫时“坐在”基质上，而沼蛙则“抓住”植被。鸣叫姿势的差异可能代表了对不对称种间竞争的一种适应反应。
