Moore A J, Gowaty P A, Moore P J
School of Biological Sciences, University of Manchester, Oxford Road, Manchester, UK.
J Evol Biol. 2003 May;16(3):523-30. doi: 10.1046/j.1420-9101.2003.00527.x.
Female mate choice has been demonstrated in a wide variety of species and is now accepted as an important factor in sexual selection. One of the remaining questions, however, is why females prefer specific males. Do females or their offspring benefit from their choice? Or do females choose mates to minimize costs of mating? Here we show that, in the ovoviviparous cockroach Nauphoeta cinerea, where sexual selection has been well documented, females chose mates to avoid costly male manipulation. Females were partnered with preferred or nonpreferred mates, and fitness of the females measured. We found that females lived longer when they mated with preferred males. Female lifespan depended on the rate at which offspring developed from egg to parturition: slower development led to longer life. We manipulated the male pheromone and showed that the component of the pheromone blend that makes males attractive to females also delayed parturition. Thus, like other aspects of sexual conflict in this species, offspring development and thereby the mother's lifespan depended on exposure of females to specific components of the male pheromone. Males benefit from manipulating offspring development because females with accelerated parturition remained unreceptive whereas females with slower developing offspring readily remated after giving birth to their offspring. Our results suggest a hormone-like role for the male pheromone in N. cinerea and provide the first direct evidence of mate choice to avoid male manipulation. This study shows that dominant males may not be preferred males if they are manipulating females, why multiple components with contrasting effects can exist in a sexual signal, and emphasizes the complex fitness relationships that can arise in species with sexual conflict.
在众多物种中都已证实存在雌性配偶选择现象，如今它已被公认为是性选择中的一个重要因素。然而，仍存在的一个问题是，为何雌性会偏好特定的雄性。雌性自身或其后代会从这种选择中受益吗？还是说雌性选择配偶是为了将交配成本降至最低？在此我们表明，在卵胎生蟑螂灰白新小绥螨（Nauphoeta cinerea）中，性选择已有充分记录，雌性选择配偶是为了避免雄性的高成本操控。让雌性与偏好或非偏好的配偶配对，并对雌性的适合度进行测量。我们发现，当雌性与偏好的雄性交配时，寿命更长。雌性的寿命取决于后代从卵发育到分娩的速度：发育较慢会导致寿命更长。我们对雄性信息素进行了操控，结果表明，使雄性对雌性具有吸引力的信息素混合物成分也会延迟分娩。因此，与该物种性冲突的其他方面一样，后代发育以及母亲的寿命取决于雌性接触雄性信息素的特定成分。雄性从操控后代发育中受益，因为分娩加速的雌性不再接受交配，而后代发育较慢的雌性在产后很容易再次交配。我们的研究结果表明，雄性信息素在灰白新小绥螨中具有类似激素的作用，并首次提供了为避免雄性操控而进行配偶选择的直接证据。这项研究表明，如果优势雄性操控雌性，它们可能并非是雌性偏好的雄性，解释了性信号中为何会存在具有相反作用的多种成分，并强调了在存在性冲突的物种中可能出现的复杂适合度关系。
