Thresholds or comparisons:: Mate choice criteria and sexual selection in a periodical cicada, Magicicada septendecim (Hemiptera: Cicadidae)
Thresholds or comparisons:: Mate choice criteria and sexual selection in a periodical cicada, Magicicada septendecim (Hemiptera: Cicadidae)
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DOI：
10.1163/1568539042245187
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发表时间：
2004-06-01
期刊：
影响因子：
1.3
通讯作者：
Marshall, DC
中科院分区：
文献类型：
--
作者：
Cooley, JR;Marshall, DC
许多昆虫拥有的生活史特征使它们不太可能使用理论讨论中隐含的相对择偶标准；因此，许多昆虫的交配群体被区别对待，称为“群体”或“合唱”。然而，周期蝉（Magicicada spp.）似乎是参与lek交配系统的强有力的候选者。我们提出了一系列的观察和实验，旨在揭示周期蝉是否存在交配偏差，以及任何偏差是否与灵活（“n最佳”选择）或固定（阈值选择）交配标准最一致。我们排除了交配后选择的可能性，因为大多数雌性只交配一次，之后就变得不愿意交配了。在我们的研究中，积极合唱的配偶之间的交配成功模式与随机交配无法区分，我们发现未交配和交配的雄性之间在体型和歌声音调上没有一致的差异，这两个标准在其他情况下与Magicicada的交配偏好有关。由于我们的研究结果与固定阈值选择机制最为一致，因此我们认为，尽管Magicicada交配聚集符合Bradbury（1981）的lek标准，但它们的功能与脊椎动物的lek方式不同。相反，魔蝉的行为特征表明，雌性的选择性可能是偶然的，因为雄性和雌性在交配繁殖方面的不平等倾向，导致性接受雄性的过剩，以及雌性在交配准备开始时被追求的频率很高。
Many insects possess life history characteristics that make them unlikely to use the kinds of relative mate choice criteria implicit in theoretical discussions of leks; thus, many insect mating aggregations are treated differently, as 'swarms' or 'choruses.' Yet periodical cicadas (Magicicada spp.) seem strong candidates for participating in lek mating systems. We present a series of observations and experiments designed to reveal whether there are mating biases in periodical cicadas and whether any biases are most consistent with flexible ('best-of-N'-choice) or fixed (threshold choice) mating criteria. We rule out postcopulatory choice by demonstrating that most females mate once, after which they become sexually unreceptive. In our study, patterns of mating success among actively chorusing mates are indistinguishable from random mating, and we uncover no consistent differences between unmated and mated males on the basis of size and song pitch, two criteria that have been associated with Magicicada mating biases in other contexts. Because our results are most consistent with a fixed-threshold choice mechanism, we suggest that Magicicada mating aggregations do not function in a manner similar to vertebrate leks even though they fulfill Bradbury's (1981) lek criteria. Instead, features of Magicicada behavior suggesting female selectivity may arise incidentally from males' and females' unequal tendencies to mate multiply, the resulting superabundance of sexually receptive males, and the high frequency at which females are courted at the onset of mating readiness.