School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
BMC Biol. 2022 Oct 31;20(1):244. doi: 10.1186/s12915-022-01438-5.
Animals can exhibit remarkable reproductive plasticity in response to their social surroundings, with profound fitness consequences. The presence of same-sex conspecifics can signal current or future expected competition for resources or mates. Plastic responses to elevated sexual competition caused by exposure to same-sex individuals have been well-studied in males. However, much less is known about such plastic responses in females, whether this represents sexual or resource competition, or if it leads to changes in investment in mating behaviour and/or reproduction. Here, we used Drosophila melanogaster to measure the impact of experimentally varying female exposure to other females prior to mating on fecundity before and after mating. We then deployed physical and genetic methods to manipulate the perception of different social cues and sensory pathways and reveal the potential mechanisms involved.
The results showed that females maintained in social isolation prior to mating were significantly more likely to retain unfertilised eggs before mating, but to show the opposite and lay significantly more fertilised eggs in the 24h after mating. More than 48h of exposure to other females was necessary for this social memory response to be expressed. Neither olfactory nor visual cues were involved in mediating fecundity plasticity-instead, the relevant cues were perceived through direct contact with the non-egg deposits left behind by other females.
The results demonstrate that females show reproductive plasticity in response to their social surroundings and can carry this memory of their social experience forward through mating. Comparisons of our results with previous work show that the nature of female plastic reproductive responses and the cues they use differ markedly from those of males. The results emphasise the deep divergence in how each sex realises its reproductive success.
动物可以对其社会环境表现出显著的生殖可塑性，从而产生深远的适应度后果。同性同种个体的存在可以暗示当前或未来对资源或配偶的竞争。由于暴露于同性个体而导致的对升高的性竞争的塑性反应在雄性中得到了很好的研究。然而，关于雌性中是否存在这种可塑性反应，以及这种反应是否代表性竞争或资源竞争，或者是否导致交配行为和/或繁殖投资的变化，人们知之甚少。在这里，我们使用黑腹果蝇来衡量在交配前实验性地改变雌性暴露于其他雌性的时间对交配前后生育力的影响。然后，我们部署了物理和遗传方法来操纵对不同社会线索和感觉途径的感知，并揭示了所涉及的潜在机制。
结果表明，在交配前被隔离饲养的雌性在交配前更有可能保留未受精的卵，但在交配后 24 小时内表现出相反的情况，并产下明显更多的受精卵。需要超过 48 小时的暴露于其他雌性才能表达这种社会记忆反应。嗅觉或视觉线索都没有参与调节生殖可塑性，而是通过与其他雌性留下的非卵沉积物直接接触来感知相关线索。
结果表明，雌性会对其社会环境表现出生殖可塑性，并可以通过交配将这种社会经验的记忆传递下去。将我们的结果与以前的工作进行比较表明，雌性的塑性生殖反应的性质及其使用的线索与雄性明显不同。结果强调了每一种性别实现其生殖成功的深刻分歧。
