Analysis of acquirement mechanism for nutritional resource in host-parasitoid interaction

寄主与寄生生物互作中营养资源获取机制分析

基本信息

批准号：
15380041
负责人：
TANAKA Toshiharu
金额：
$ 9.66万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

The nutritional relationship that is established between hosts and their parasites is never simple and often reflects a long co-evolutionary ‘arms-race' between each other. In this arms-race, hosts evolve mechanisms that enable them to escape from their parasites or to eliminate them ; on the other hand, the parasites need to overcome host defenses and utilize the host as a nutritional reservoir. The parasitoid larvae feed selectively on certain host tissues in order to keep a minimal damage to the host. Severe damage of the host during early development may lead to precocious death of the parasitoid. Feeding exclusively on the nutrient-rich hemolymph is one strategy that parasitoid. larvae employed to minimize host damage. Hemolymph retains a high nutritional value since it efficiently retrieves nutrients, which have already been or are to be stored in organs like the fat body via a specialized metabolic pathway, through inhibition of absorption of nutrients by the fat body, or only by slowly reducing the amount of fat body. The koinobiont larvae, however, possess well-developed gut to digest some foods during their late stages. Also, during late larval stages, the parasitoid larvae exhibit rapid growth just prior to pupation. These facts are difficult to explain on the sole basis of nutrient uptake from host hemolymph. Elucidation of how ecto- and endo-parasitic koinobionts utilize the hosts as a food resource will be useful in clarifying the evolution of common or different strategies in koinobionts. We studied strategies that enable parasitoids to ensure a sufficient food resource in both ecto- and endoparasitic koinobionts and explain how the parasitoid larvae utilize the host resource to enhance successful parasitism.

寄主及其寄生虫之间建立的核关系从来都不是简单的，并且经常反映出彼此之间长期的共同进化的“武器”。在这种武器竞争中，主持人的发展机制使他们能够从寄生虫中逃脱或消除它们。另一方面，寄生虫需要克服宿主防御力并将宿主用作营养储层。寄生虫幼虫在某些宿主组织上有选择地进食，以使宿主造成最小的损害。早期发育过程中宿主的严重损害可能导致寄生虫早熟。仅以营养丰富的血淋巴为食是一种寄生的一种策略。幼虫用来最大程度地减少宿主损害。血淋巴保留了高营养价值，因为它可以通过专门的代谢途径有效检索已经或要通过脂肪体抑制脂肪的吸收，或者仅通过慢慢减少脂肪体的含量来抑制营养物体的吸收，从而有效地检索已经或要通过专门的代谢途径来存储在脂肪体等器官中。然而，koinobiont幼虫具有发达的肠道，可以在晚期消化一些食物。同样，在幼虫阶段，寄生虫幼虫在化合物之前就表现出快速生长。这些事实很难以宿主血淋巴的营养摄取的唯一基础来解释。阐明寄生虫和寄生虫koinobionts如何利用宿主作为食物资源将很有用，这将有用。我们研究了使寄生虫能够确保寄生虫和内寄生虫的足够食物资源的策略，并解释了寄生虫幼虫如何利用宿主资源来增强成功的寄生虫。