Gottsberger Brigitte, Mayer Frieder
Department of Zoology II, University of Erlangen-Nürnberg, Staudtstrasse 5, Erlangen, Germany.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2007 Jul;193(7):703-14. doi: 10.1007/s00359-007-0225-y. Epub 2007 Apr 18.
The effectiveness of hybridization barriers determines whether two species remain reproductively isolated when their populations come into contact. We investigated acoustic mating signals and associated leg movements responsible for song creation of hybrids between the grasshopper species Chorthippus biguttulus and C. brunneus to study whether and how songs of male hybrids contribute to reproductive isolation between these sympatrically occurring species. Songs of F1, F2, and backcross hybrids were intermediate between those of both parental species in terms phrase number and duration. In contrast, species-specific syllable structure within phrases was largely lost in hybrids and was produced, if at all, in an irregular and imperfect manner. These divergences in inheritance of different song parameters are likely the result of incompatibility of neuronal networks that control stridulatory leg movements in hybrids. It is highly probable that songs of hybrid males are unattractive to females of either parental species because they are intermediate in terms of phrase duration and lack a clear syllable structure. Males of various hybrid types (F1, F2, and backcrosses) are behaviorally sterile because their songs fail to attract mates.
杂交屏障的有效性决定了两个物种的种群接触时它们是否仍保持生殖隔离。我们研究了草蜢物种大斑草螽（Chorthippus biguttulus）和褐草螽（C. brunneus）之间杂种的声学交配信号以及与鸣叫产生相关的腿部运动，以研究雄性杂种的鸣声是否以及如何促成这些同域分布物种之间的生殖隔离。F1、F2和回交杂种的鸣声在乐句数量和时长方面介于两个亲本物种之间。相比之下，乐句内物种特异性的音节结构在杂种中基本丧失，即便产生，也是以不规则且不完美的方式。不同鸣声参数遗传上的这些差异可能是由于控制杂种中摩擦发音腿部运动的神经网络不兼容所致。杂种雄性的鸣声很可能对任一亲本物种的雌性都没有吸引力，因为它们在乐句时长方面处于中间状态且缺乏清晰的音节结构。各种杂种类型（F1、F2和回交）的雄性在行为上是不育的，因为它们的鸣声无法吸引配偶。
