Developmental Polymorphism Induced by Intraspecific Predation in the Ciliated Protozoon Onychodromus quadricornutus
Developmental Polymorphism Induced by Intraspecific Predation in the Ciliated Protozoon Onychodromus quadricornutus
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纤毛原生动物四角甲虫种内捕食诱导的发育多态性
DOI：
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发表时间：
1988
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影响因子：
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通讯作者：
B. Wicklow
中科院分区：
文献类型：
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作者：
B. Wicklow
摘要。四角爪蜥（Onychodromus quadricornutus）是一种具有巨大体型（可达900 μm）、独特的四个背刺或背角以及种内捕食诱导的两种发育多态性的动物。细胞长度的频率在复制一个良好的喂养克隆显示正态分布，饥饿，然后种内捕食，但是，诱导细胞内的克隆转化成两个大小类：小披针形细胞和食人巨人。诱导实验表明，食人巨人释放的一种物质在24小时内刺激克隆动物的防御性脊柱生长。巨人也可以诱导脊柱生长在非克隆。此外，O. quadricornutus细胞暴露于捕食性纤毛虫Lembadion magnum也会发育出肥大的棘。选择实验表明，同种巨人捕食具有未发育的刺（长度为40 μm）的细胞。对相似大小的O. quadricornutus细胞分为两个不同的大小类可能会增加潜在的猎物大小的范围提供给O。quadricornutus种群;肥大的刺似乎作为一种诱导防御系统，以抵御系统中出现的间歇性捕食者，包括同种巨人。这是首次报道的防御性发育多态性引起的种内捕食。
ABSTRACT. The hypotrich ciliate Onychodromus quadricornutus is remarkable in its potential for voluminous size (up to 900 μm in length), its possession of a unique set of four dorsal spines or horns, and its capability to express two kinds of developmental polymorphism induced by intraspecific predation. Cell length frequencies in replicates of a well-fed clone show normal distributions; starvation followed by intraspecific predation, however, induces cells within a clone to transform into two size classes: small lanceolate cells and cannibal giants. Induction experiments indicate that a substance released by cannibal giants stimulates defensive spine growth in clonemates within 24 h. Giants can also induce spine growth in non-clonemates. Furthermore, O. quadricornutus cells exposed to the predacious ciliate Lembadion magnum also develop hypertrophied spines. Selection experiments show that conspecific giants prey on cells with undeveloped spines ( 40 μm in length). Transformation of a population of similarly sized O. quadricornutus cells into two different size classes may function to increase the range of potential prey sizes available to the O. quadricornutus population; hypertrophied spines appear to function as an inducible defense against intermittent predators appearing in the system including conspecific giants. This is the first reported case of a defensive developmental polymorphism induced by intraspecific predation.