The benefits of clustering eggs: the role of egg predation and larval cannibalism in a predatory mite
The benefits of clustering eggs: the role of egg predation and larval cannibalism in a predatory mite
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卵聚集的好处：卵捕食和幼虫同类相食在捕食性螨中的作用
DOI：
10.1007/s00442-001-0846-8
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发表时间：
2002
期刊：
影响因子：
2.7
通讯作者：
M. Sabelis
中科院分区：
文献类型：
--
作者：
F. Faraji;A. Janssen;M. Sabelis
抽象的。许多节肢动物产生一簇簇的卵子，但对于卵子聚集的进化仍然缺乏明确的解释。我们检验了几个关于捕食性螨类退化伊菲斯虫产生卵簇的假设。这种捕食者以花粉、蓟马幼虫和花中的花蜜为食，但产卵成簇地聚集在叶毛(粉螨)中，在那里卵被蓟马杀死的风险较低，蓟马是这种捕食性螨类的猎物。观察到的集群并不是由于产卵地点不足引起的；雌性更喜欢在有卵的洞穴中产卵，而不是在空巢中产卵。为了解释这种偏好，我们首先检查了卵群对同类相食风险的影响。我们发现，卵是不会同类相食的，而从单个卵或集群中出现的幼虫同样容易受到伤害。随后，我们考虑了由猎物，即西花蓟马的反击造成的卵的死亡。我们没有发现任何迹象表明，一群卵可以保护卵免受蓟马的捕食。然而，当虫卵聚集在虫口而不是散布在虫口时，被蓟马杀死的虫卵比例较低。因此，成群产卵对其本身没有影响，而成群产卵降低了蓟马的捕食风险，但成群产卵对捕食者卵的存活有协同作用。这种协同效应的产生可能是因为蓟马更难接触到簇生在叶毛中的卵。这些实验突出了对卵聚集的一种新解释，即适应反击猎物。此外，研究还表明，植物能保护捕食者的卵不被捕食。
Abstract. Many arthropods produce clusters of eggs, but an unambiguous explanation for the evolution of egg clustering is still lacking. We test several hypotheses for the production of egg clusters by the predatory mite Iphiseius degenerans. This predator feeds on pollen, thrips larvae and nectar in flowers, but oviposits in clusters in tufts of leaf hairs (acarodomatia), where eggs run a lower risk of being killed by thrips, the prey of this predatory mite. The observed clustering is not caused by a shortage of oviposition sites; females preferably oviposit in a domatium containing eggs rather than in an empty domatium. To explain this preference, we first examined the effect of egg clusters on the risk of cannibalism. We found that eggs are invulnerable to cannibalism, whereas larvae emerging from single eggs or from clusters were equally vulnerable. Subsequently, we considered the killing of eggs resulting from counter-attacks by prey, i.e. the western flower thrips. We found no indication that a cluster of eggs protects eggs from predation by thrips. However, when eggs were clustered in a domatium rather than scattered over domatia, the proportion of eggs killed by thrips was lower. Hence, oviposition in clusters has no effect on its own and oviposition in domatia reduces predation risk by thrips, but oviposition in clusters in domatia leads to a synergistic effect on the survival of predator eggs. This synergism probably arises because eggs in clusters within tufts of leaf hairs are more difficult for thrips to reach. These experiments highlight a novel explanation of egg clustering, i.e. adaptation to counter-attacking prey. Moreover, they show that plant domatia protect predator eggs from predation.