Postmating-prezygotic isolation between two allopatric populations of Drosophila montana: fertilisation success differs under sperm competition.
Postmating-prezygotic isolation between two allopatric populations of Drosophila montana: fertilisation success differs under sperm competition.
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DOI：
10.1002/ece3.1995
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发表时间：
2016-03
影响因子：
2.6
通讯作者：
Veltsos P
中科院分区：
文献类型：
--
作者：
Ala-Honkola O;Ritchie MG;Veltsos P
交配后但合子前（PMPZ）的相互作用越来越多地被认为是生殖隔离进化中潜在的重要早期障碍。最近的一项研究描述了同一物种种群之间的一个潜在例子：蒙大拿果蝇种群之间的单次交配导致了不同的受精成功率，因为一个种群（温哥华）的精子无法穿透另一个种群（科罗拉多）的卵子。作为D. montana是一雄多熟的（雌性很快再交配），我们在相同的种群之间建立了所有可能的杂交的双交配，以测试射精之间的竞争效应是否影响这种PMPZ隔离。我们测量了无选择试验中的交配前隔离，单次和双次交配后的雌性生殖力，生育力和卵到成虫的存活率以及第二次雄性亲子鉴定成功率（P2）。令人惊讶的是，我们发现没有PMPZ生殖隔离的两个群体之间的竞争环境下，表明没有困难的精子从温哥华男性受精科罗拉多鸡蛋后，双交配。虽然P2随时间的变化存在细微差异，表明温哥华男性的精子在科罗拉多女性中的第一男性角色中竞争力较低，但这些影响并没有转化为整体P2的差异。因此，在竞争性和非竞争性条件下，受精的成功率会有很大的不同，这可能是因为第二次交配的雄性在精子竞争中产生了更高质量的射精。我们认为，不像在更不同的物种比较，精子竞争通常会增加生殖隔离，射精剪裁可以减少PMPZ隔离的潜力时，最近分化的人群杂交。
Postmating but prezygotic (PMPZ) interactions are increasingly recognized as a potentially important early‐stage barrier in the evolution of reproductive isolation. A recent study described a potential example between populations of the same species: single matings between Drosophila montana populations resulted in differential fertilisation success because of the inability of sperm from one population (Vancouver) to penetrate the eggs of the other population (Colorado). As the natural mating system of D. montana is polyandrous (females remate rapidly), we set up double matings of all possible crosses between the same populations to test whether competitive effects between ejaculates influence this PMPZ isolation. We measured premating isolation in no‐choice tests, female fecundity, fertility and egg‐to‐adult viability after single and double matings as well as second‐male paternity success (P2). Surprisingly, we found no PMPZ reproductive isolation between the two populations under a competitive setting, indicating no difficulty of sperm from Vancouver males to fertilize Colorado eggs after double matings. While there were subtle differences in how P2 changed over time, suggesting that Vancouver males’ sperm are somewhat less competitive in a first‐male role within Colorado females, these effects did not translate into differences in overall P2. Fertilisation success can thus differ dramatically between competitive and noncompetitive conditions, perhaps because the males that mate second produce higher quality ejaculates in response to sperm competition. We suggest that unlike in more divergent species comparisons, where sperm competition typically increases reproductive isolation, ejaculate tailoring can reduce the potential for PMPZ isolation when recently diverged populations interbreed.