Hochkirch A, Bücker A, Gröning J
University of Osnabrück, Department of Biology/Chemistry, Division of Ecology, Barbarastrasse 13, D-49076 Osnabrück, Germany.
Bull Entomol Res. 2008 Dec;98(6):605-12. doi: 10.1017/S0007485308005907.
The coexistence of closely related species is often hampered by resource competition or reproductive interference (interspecific sexual interactions). Species utilising similar signal channels might face substantial problems when they co-occur. It has, therefore, been suggested that reinforcement might drive signal evolution in narrow suture zones of secondary contact. However, species with large overlapping ranges are usually not believed to interact sexually. The Slender Ground-hopper, Tetrix subulata, and the Common Ground-hopper, Tetrix undulata (Orthoptera: Tetrigidae) are sister species, which occur sympatrically in large parts of western and Central Europe, but rarely share the same habitat. It has been hypothesized that reproductive interference might account for their missing coexistence. Here, we test experimentally whether these two species interact sexually. Our results suggest an incomplete premating isolation of these ground-hoppers, as we recorded heterospecific courtship, mating attempts and mating. The number of conspecific copulations and mating attempts of T. subulata decreased substantially in the presence of T. undulata, whereas the latter species was not negatively affected. Males of both species preferred to approach females of T. undulata, whereas females of both species did not discriminate against heterospecific males. Further studies on the reproductive success are needed to clarify whether reproductive interference might influence habitat partitioning between these species.
亲缘关系相近的物种共存往往会受到资源竞争或生殖干扰（种间性相互作用）的阻碍。利用相似信号通道的物种在同域分布时可能会面临重大问题。因此，有人提出在二次接触的狭窄缝合带中，强化作用可能会推动信号进化。然而，通常认为分布范围大量重叠的物种不会发生性相互作用。细地蝗（Tetrix subulata）和普通地蝗（Tetrix undulata，直翅目：蚱科）是姐妹物种，它们在西欧和中欧的大部分地区同域分布，但很少共享相同的栖息地。据推测，生殖干扰可能是它们未能共存的原因。在此处，我们通过实验测试这两个物种是否会发生性相互作用。我们的结果表明这些地蝗存在不完全的交配前隔离，因为我们记录到了种间求偶、交配尝试和交配行为。在有普通地蝗存在的情况下，细地蝗的同种交配和交配尝试数量大幅减少，而普通地蝗并未受到负面影响。两个物种的雄性都更倾向于接近普通地蝗的雌性，而两个物种的雌性都不会区分异种雄性。需要进一步研究生殖成功率，以阐明生殖干扰是否可能影响这些物种之间的栖息地划分。
