Males and females evolve riskier traits in populations with eavesdropping parasitoids
Males and females evolve riskier traits in populations with eavesdropping parasitoids
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DOI：
10.1007/s00265-018-2588-1
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发表时间：
2018-11-01
影响因子：
2.3
通讯作者：
Wagner, William E., Jr.
中科院分区：
文献类型：
--
作者：
Beckers, Oliver M.;Wagner, William E., Jr.
捕食和/或寄生常常限制显着的雄性特征和雌性偏好的进化，因为显着的特征会吸引捕食者或寄生虫，而雌性与吸引捕食者或寄生虫的雄性交往的成本很高。因此，与低风险人群中的个体相比，高风险人群中的雄性和雌性预计会进化出更安全的交配行为。我们在田间蟋蟀 Gryllus lineaticeps 中测试了这种对抗性选择假说。雄性蟋蟀会发出鸣叫声，而雌性蟋蟀和窃听寄生蝇 Ormia ochracea 都喜欢更快的鸣叫频率。苍蝇在繁殖季节后期攻击田间蟋蟀，被寄生的蟋蟀死亡。我们使用常见的花园饲养设计来测试高风险人群和低风险人群之间在歌曲和偏好方面的进化差异。与对抗性选择假说的预测相反，来自高风险人群的雄性产生更快（风险更高）的鸣叫率，而雌性更喜欢更快的鸣叫率。我们建议，晚季寄生选择增加对生殖性状的投资，以在拟寄生物活动出现之前最大化繁殖（晚季寄生假说），这至少可以解释高风险人群中女性的风险偏好和男性歌曲的潜在风险。因此，捕食和寄生可能对生殖行为的进化产生多种意想不到的影响，具体取决于捕食者或寄生虫引起的死亡率的时间模式。意义说明交配信号通常很明显，不仅吸引伴侣，还吸引捕食者和寄生虫。即使是沉默的交配伙伴也可能通过与信号发出者的联系而遭受捕食或寄生。在这种情况下，人们通常认为自然选择和性选择是相反的，有效地限制了显着信号和偏好的演变。我们证明，一只偷听的寄生蝇导致了田间蟋蟀的偏好和潜在歌曲的进化，其方向与对抗性选择预测的相反、更明显。我们认为，与繁殖季节相关的寄生时间模式可能导致这种意想不到的进化模式。我们提出季末寄生假说作为对抗性选择假说的替代方案，这可能更好地解释经历季节性捕食或寄生的其他物种中更显着的交配特征值。
Predation and/or parasitism often limits the evolution of conspicuous male traits and female preferences because conspicuous traits can attract predators or parasites and it is costly for females to associate with males that attract predators or parasites. As a result, males and females in high-risk populations are expected to evolve safer mating behaviors compared to individuals from low-risk populations. We tested this antagonistic selection hypothesis in the field cricket Gryllus lineaticeps. Males produce chirped songs, and both female crickets and the eavesdropping parasitoid fly Ormia ochracea prefer faster chirp rates. The flies attack the field crickets late in the breeding season and parasitized crickets die. We used a common garden rearing design to test for evolved differences in songs and preferences between high- and low-risk populations. In contrast to predictions of the antagonistic selection hypothesis, males from high-risk populations produced faster (riskier) chirp rates and females preferred faster chirps. We suggest that late-season parasitism selects for increased investment in reproductive traits to maximize reproduction before the advent of parasitoid activity (late-season parasitism hypothesis), which would at least explain riskier female preferences and potentially riskier male songs in the high-risk populations. Predation and parasitism may thus have diverse and unexpected effects on the evolution of reproductive behavior, depending upon the temporal pattern of predator- or parasite-induced mortality.Significance statementMating signals are typically conspicuous and not only attract partners but also predators and parasites. Even the silent mating partner may experience predation or parasitism by associating with the signaler. Under these circumstances, it is commonly assumed that natural and sexual selection act in opposite directions, effectively limiting the evolution of conspicuous signals and preferences. We demonstrate that an eavesdropping parasitic fly caused the evolution of preferences, and potentially songs, in a field cricket in the opposite, more conspicuous, direction than predicted by antagonistic selection. We argue that the temporal pattern of parasitism in relation to the reproductive season likely causes this unexpected evolutionary pattern. We propose the late-season parasitism hypothesis as an alternative to the antagonistic selection hypothesis, which might better explain more conspicuous mating trait values in other species that experience seasonal predation or parasitism.