Intraguild predation in larval parasitoids: implications for coexistence
Intraguild predation in larval parasitoids: implications for coexistence
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DOI：
10.1046/j.1365-2656.2002.00660.x
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发表时间：
2002-11-01
影响因子：
4.8
通讯作者：
Borer, ET
中科院分区：
文献类型：
--
作者：
Borer, ET
1. 许多共存的拟寄生物通过种群内捕食相互作用（IGP）；然而，在没有阶段结构的IGP理论中，捕食者和猎物通过这一机制仅在一个相对狭窄的参数空间区域内共存。最近一项关于IGP理论的阐述表明，与没有阶段结构的IGP理论预测相比，公会成员之间的共存可能发生在更大范围的资源生产率范围内。这些一般的理论预测被用于探索加利福尼亚红鳞上共存的一对拟寄生虫——melinus （DeBach）和Encarsia perniciosi （Tower）共存的含义。对已发表的两种拟寄生虫之间的实验室竞争实验的重新分析表明，当被再寄生的宿主含有更发达的幼年拟内寄生虫（Encarsia）时，拟外寄生虫Aphytis的存活率较低。这种模式与一种普遍的假设相反，即在一个共同的宿主中，外寄生体总是消耗内寄生体，并可能影响共存。该实验仅覆盖了Encarsia开发期间的第一个阶段，约占30%，并且没有描述Encarsia的结果，因此这种相互作用在IGP背景下的动态影响仍不清楚。此外，与葡萄球菌相比，Encarsia能够寄生在更年轻的宿主身上，而这一点在实验中没有得到检验。重复实验，并延长至覆盖恩卡西亚的整个发育时期。另一项实验是为了探索Encarsia是否可以通过攻击年轻宿主来先发制人。发现葡萄球菌幼虫的存活率随其所处幼虫的年龄而下降。当Encarsia寄生在非常年轻的宿主上时，它越来越不容易受到葡萄球菌的攻击，并且越来越有可能存活到羽化。然而，在形成一个无懈可击的假毛虫之前，恩卡西亚总是在较大的宿主中被杀死，而不管它在葡萄球菌攻击时的年龄。根据阶段结构的IGP理论，Aphytis成功的下降与无孔不入的Encarsia阶段相结合可能促进了该系统的共存。
1. Many coexisting parasitoids interact via intraguild predation (IGP); however, in IGP theory without stage structure the intraguild predator and intraguild prey coexist via this mechanism over only a relatively narrow region of parameter space. A recent formulation of IGP theory with a stage of the intraguild prey species that is invulnerable to attack by the intraguild predator shows that coexistence between guild members can occur across a much broader range of resource productivity than is predicted by IGP theory without stage structure. These general theoretical predictions are used to explore the implications for coexistence of Aphytis melinus (DeBach) and Encarsia perniciosi (Tower), a pair of parasitoids that coexist on California red scale.2. Reanalysis of a published laboratory competition experiment between two parasitoid species suggests that Aphytis, an ectoparasitoid, survives at a lower rate when the reparasitized host contains a more developed juvenile endoparasitoid (Encarsia). This pattern is contrary to a common assumption that ectoparasitoids always consume endoparasitoids in a shared host, and may affect coexistence. The experiment covered only the first similar to30% of the Encarsia development period and did not describe the outcome for Encarsia, so the dynamic effects of this interaction in the context of IGP remain unclear. In addition, Encarsia is capable of parasitizing much younger hosts than is Aphytis, which the experiment did not examine.3. The experiment was repeated, and extended to cover the full developmental duration of Encarsia. An additional experiment was performed to explore whether Encarsia could pre-empt Aphytis by attacking younger hosts. Aphytis juvenile survival was found to decrease as a function of the age of the juvenile Encarsia onto which it was laid. When Encarsia parasitized very young hosts, it was increasingly invulnerable to attack by Aphytis and increasingly more likely to survive to emergence. However, until the formation of an invulnerable pseudomoult, Encarsia was always killed in larger hosts, regardless of its age at the time of Aphytis attack.4. According to stage-structured IGP theory, the decline in Aphytis success combined with an invulnerable Encarsia stage may promote coexistence in this system.