Rapidly changing environments impose novel selection pressures on organisms, and sometimes adaptive phenotypic plasticity allows organisms to survive and reproduce in the face of environmental change. However, plastic responses can also be maladaptive. In this study, we investigate whether male reproductive investment responds plastically to varied experience with traffic noise. We exposed male crickets chronically to one of three noise treatments from the 2nd-3rd instar until their natural death: masking traffic noise (including noise that overlaps in frequency with the male crickets’ mating calls), non-masking traffic noise (an identical traffic noise track from which we digitally removed the frequencies that mask the crickets’ mating call), and silence. We dissected and weighed their testes and spermatophore molds. Controlling for body mass, we found that the spermatophore molds of crickets reared in masking and non-masking noise were 29% and 24% lighter, respectively, than those of crickets reared in silence. There were no differences in body mass-adjusted testes mass among treatments. If spermatophore mold mass is positively associated with male reproductive output, this reduction in size could have negative fitness consequences for animals exposed to traffic noise. We encourage future work to investigate impacts of noise on reproductive investment in other study systems that are likely sensitive to anthropogenic noise (e.g., birds, frogs, singing insects). Anthropogenic noise is a pervasive pollutant and chronic noise can negatively affect fitness. How does anthropogenic noise influence reproductive investment? Phenotypically plastic responses to noise may increase survival and reproduction in noisy environments. Traffic noise masks the sounds crickets make, potentially changing conspecifics’ perception of population density, mate availability, and the risk of sperm competition. We found that male crickets reared in silence developed significantly larger spermatophore molds (a reproductive structure that delivers the sperm containing packet to the female) than those reared in traffic noise. If the spermatophore mold influences male reproductive output, this reduction in size may have negative impacts on reproductive success of animals exposed to masking traffic noise.

中文翻译：

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人为噪声减少了雄性对声学信号昆虫的生殖投资

快速变化的环境对生物体施加了新的选择压力，有时适应性表型可塑性允许生物体在环境变化面前生存和繁殖。然而，塑料反应也可能是适应不良的。在这项研究中，我们调查了男性生殖投资是否对交通噪音的各种体验有可塑性的反应。我们将雄性蟋蟀从 2 至 3 龄期长期暴露于三种噪音处理中的一种，直到它们自然死亡：掩蔽交通噪音（包括与雄蟋蟀交配频率重叠的噪音）、非掩蔽交通噪音（相同的交通噪音）我们以数字方式去除了掩盖蟋蟀交配叫声的频率）和静音。我们解剖并称重了它们的睾丸和精囊霉菌。控制体重，我们发现，在掩蔽和非掩蔽噪音中饲养的蟋蟀的精囊霉菌比安静饲养的蟋蟀分别轻 29% 和 24%。治疗之间体重调整后的睾丸质量没有差异。如果精囊霉菌质量与雄性生殖量呈正相关，那么这种尺寸的减少可能会对暴露于交通噪音的动物产生负面的健康影响。我们鼓励未来开展工作，调查噪声对可能对人为噪声敏感的其他研究系统（例如鸟类、青蛙、唱歌昆虫）中的生殖投资的影响。人为噪音是一种普遍的污染物，慢性噪音会对健康产生负面影响。人为噪声如何影响生殖投资？对噪音的表型塑性反应可能会增加在嘈杂环境中的生存和繁殖。交通噪音掩盖了蟋蟀发出的声音，可能会改变同种动物对人口密度、配偶可用性和精子竞争风险的看法。我们发现，与在交通噪音中饲养的雄性蟋蟀相比，在安静环境中饲养的雄性蟋蟀发育出明显更大的精囊霉菌（一种将含有精子的包送给雌性的生殖结构）。如果精囊霉菌会影响雄性的生殖量，那么体型的减小可能会对暴露在交通噪音中的动物的繁殖成功率产生负面影响。可能会改变同种动物对人口密度、配偶可用性和精子竞争风险的看法。我们发现，与在交通噪音中饲养的雄性蟋蟀相比，在安静环境中饲养的雄性蟋蟀发育出明显更大的精囊霉菌（一种将含有精子的包送给雌性的生殖结构）。如果精囊霉菌会影响雄性的生殖量，那么体型的减小可能会对暴露在交通噪音中的动物的繁殖成功率产生负面影响。可能会改变同种动物对人口密度、配偶可用性和精子竞争风险的看法。我们发现，与在交通噪音中饲养的雄性蟋蟀相比，在安静环境中饲养的雄性蟋蟀发育出明显更大的精囊霉菌（一种将含有精子的包传递给雌性的生殖结构）。如果精囊霉菌会影响雄性的生殖量，那么体型的减小可能会对暴露在交通噪音中的动物的繁殖成功率产生负面影响。