BACKGROUND The hybridizing field crickets, Gryllus firmus and Gryllus pennsylvanicus have several barriers that prevent gene flow between species. The behavioral pre-zygotic mating barrier, where males court conspecifics more intensely than heterospecifics, is important because by acting earlier in the life cycle it has the potential to prevent a larger fraction of hybridization. The mechanism behind such male mate preference is unknown. Here we investigate if the female cuticular hydrocarbon (CHC) profile could be the signal behind male courtship. RESULTS While males of the two species display nearly identical CHC profiles, females have different, albeit overlapping profiles and some females (between 15 and 45%) of both species display a male-like profile distinct from profiles of typical females. We classified CHC females profile into three categories: G. firmus-like (F; including mainly G. firmus females), G. pennsylvanicus-like (P; including mainly G. pennsylvanicus females), and male-like (ML; including females of both species). Gryllus firmus males courted ML and F females more often and faster than they courted P females (p < 0.05). Gryllus pennsylvanicus males were slower to court than G. firmus males, but courted ML females more often (p < 0.05) than their own conspecific P females (no difference between P and F). Both males courted heterospecific ML females more often than other heterospecific females (p < 0.05, significant only for G. firmus males). CONCLUSIONS Our results suggest that male mate preference is at least partially informed by female CHC profile and that ML females elicit high courtship behavior in both species. Since ML females exist in both species and are preferred over other heterospecific females, it is likely that this female type is responsible for most hybrid offspring production.

中文翻译：

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雌性表皮碳氢化合物（CHC）轮廓对雄性求爱行为的影响，在两个杂交田field Gryllus firmus和Gryllus pennsylvanicus。

背景技术杂交田field，坚固的灰ry和灰质的灰ry具有阻止基因在种间流动的几种障碍。行为上的合子前交配障碍是重要的，因为雄性比异种具有更强的同种优势，因为通过在生命周期中更早地行动，它有可能阻止更大比例的杂交。这种男性伴侣偏爱的机制尚不清楚。在这里，我们调查女性的表皮碳氢化合物（CHC）配置文件是否可能是男性求爱的信号。结果虽然两个物种的雄性显示出几乎相同的CHC分布图，但雌性却具有不同的特征，尽管它们具有重叠的分布，并且两种物种的某些雌性（介于15％和45％之间）都呈现出不同于典型雌性的雄性状。我们将CHC雌性的概况分为三类：牢固的G.（F；主要包括坚硬的G.女性），宾夕法尼亚州的G. pennsylvanicus（主要；主要包括宾夕法尼亚州的G. pennsylvanicus）和男性的M.（ML;包括女性）两种）。雄性灰鼠男性比雌性女性更频繁，更频繁地向ML和F女性求爱（p <0.05）。宾夕法尼亚州灰鼠男性比坚硬革兰男性的出庭速度慢，但与自己的同种雌性女性相比，向雄性雌性女性求爱的频率更高（p <0.05）（P和F之间没有差异）。男性比异性雌性更倾向于异性雌性（ML）雌性（p <0.05，仅对坚硬革兰氏雄性有显着性）。结论我们的研究结果表明，雄性配偶的偏好至少部分由雌性CHC资料提供，而ML雌性在这两个物种中都引起较高的求爱行为。由于ML雌性都存在于这两个物种中，并且比其他异种雌性更受青睐，因此这种雌性类型可能是大多数杂种后代生产的原因。