Multiple post-mating barriers to hybridisation in field crickets

Mechanisms that prevent different species from interbreeding are fundamental to the maintenance of biodiversity. Barriers to interspecific matings, such as failure to recognize a potential mate, are often relatively easy to identify. Those occurring after mating, such as differences in the how successful sperm are in competition for fertilisations, are cryptic and have the potential to create selection on females to mate multiply as a defence against maladaptive hybridization. Cryptic advantages to conspecific sperm may be very widespread and have been identified based on the observations of higher paternity of conspecifics in several species. However, a relationship between the fate of sperm from two species within the female and paternity has never been demonstrated. We use competitive microsatellite PCR to show that in two hybridising cricket species, Gryllus bimaculatus and G. campestris, sequential cryptic reproductive barriers are present. In competition with heterospecifics, more...

阻止不同物种间杂交的机制，是维持生物多样性的核心基础。种间交配障碍（Interspecific Mating Barriers）——例如无法识别潜在配偶——通常较易被识别。而交配后发生的障碍（如精子在受精竞争中的成功率差异）则较为隐蔽，且可能对雌性施加选择压力，使其通过多次交配来抵御适应性不良的杂交（Maladaptive Hybridization）。同种精子的隐蔽竞争优势可能极为普遍，这一点已通过多个物种种内父权比例更高的观测结果得到证实。然而，雌性体内两种物种的精子命运与父权之间的关联，此前从未被证实。本研究采用竞争性微卫星PCR（microsatellite PCR）技术证实，在两种杂交蟋蟀——双斑蟋蟀（Gryllus bimaculatus）与田野蟋蟀（Gryllus campestris）——中，存在连续性的隐蔽生殖屏障。在与异种精子的竞争中，更多……