雌性蜻蜓躲避求爱有高招——装死

诸平

据物理学家组织网（Phys.org）2017年5月1日的报道，瑞士苏黎世大学（University of Zurich）的生物学家发现卵子已经受精的雌蜻蜓，它会以装死的方式来躲避再与其它雄性蜻蜓的交配，详见图2（Fig. 2.）所示，此项研究成果于2017年4月24日已经在《生态学》（Ecology）杂志网站发表——Rassim Khelifa. Faking death to avoid male coercion: extreme sexual conflict resolution in a dragonfly. Ecology, First published: 24 April 2017, DOI: 10.1002/ecy.1781。更多信息请浏览原文（见附件ecy1781.pdf）或者Female dragonflies found to fake death to avoid male advances

为了便于阅读，特将Female dragonflies found to fake death to avoid male advances转载如下，仅供参考。

Female dragonflies found to fake death to avoid male advances

May 1, 2017 by Bob Yirka report

Credit: CC0 Public Domain

(Phys.org)—A biologist with the University of Zurich has discovered a species of dragonfly whose females play dead to avoid copulating with other males once her eggs have already been fertilized. In his paper published in the journal Ecology, Rassim Khelifa recalls his first experience with a female mooreland hawker dragonfly playing dead, and what he found after further study of the species.

As Khelifa describes it, he was out collecting larvae in the Swiss Alps one day, when he happened to notice one dragonfly chasing another—suddenly, the one being chased simply stopped flying and crashed to the ground, belly up. The pursuer, he notes, paused for a moment, then moved on. As Khelifa approached the dragonfly on the ground he noted it was female and then was surprised when she suddenly awoke, turned over and flew away.

Intrigued, and suspecting the behavior was intentional, Khelifa initiated a study of the species in their native environment, watching 31 male/female pursuits over time. He reports that the females tried the fake death routine 27 times, and that it worked 21 times. He notes further that in each of the fake death attempts, the female had just left her eggs, or was on her way to tend to them again.

After noting the fake death behavior, Khelifa reports that it makes sense for the female hawker, because unlike other species of dragonfly, the males do not quit attempting to mate once finding success, nor do males assist in protecting the eggs. He notes also that with the hawker species, the males have the ability to pull sperm from prior males out of the female reproductive tract with their penises, and perhaps even worse, can cause damage if he mates with a female that has already laid her eggs.

Khelifa also notes that the females tended to hide among dense vegetation when searching for food, likely another means for warding off ardent male pursuers. He points out that the feigned death behavior is the first observed in a dragonfly, but suggests it likely occurs with other species with females that go it alone after laying their eggs.

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