Influence of predator defense mechanisms on predator-prey interactions in forest food-webs

捕食者防御机制对森林食物网中捕食者-猎物相互作用的影响

• 批准号: 419020906
• 负责人: Dr. Katja Wehner
• 金额: --
• 依托单位: Arbeitsgruppe Ecological Networks
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/419020906?language=en
• 关键词: Influence; predator; defense; mechanisms; prey

Predation is an important factor that influences species interactions and may affect species distribution among forest microhabitats. The functional response of predation is shaped by multiple factors (search- and handling-time, size and body mass, population densities of predator and prey). However, many prey species have evolved defensive traits that significantly influence the predation success. Predator-prey interactions of soil arthropods in forest microhabitats are complex and difficult to monitor in nature due to the small size of the species involved and the complexity of the microhabitats. Oribatid mites are ideal models to investigate the structure and dynamics of predator-prey interactions in forest microhabitats because (a) they are extremely old and among the first animals on land, (b) they are ubiquitous on tree bark, in grassy sods, litter, dead wood, mosses and lichens and may play an important role as prey organisms in forest food webs due to their high abundances and (c) they evolved several effective predator-defense mechanisms and hence were hypothesized to somehow live in a functional “enemy-free space”. Predator-defense mechanisms in adult oribatids comprise morphological and chemical aspects. Morphological adaptations are permanent and comprise strong hardening of the cuticle, ptychoidy, and pteromorphes. Chemical defense is a dynamical mechanism based on the secretion of complex mixtures of aromatics, terpenes, hydrocarbons, alkaloids and cyanogenic compounds. The distribution of oribatid mite species with either morphological and/or chemical defense in different forest microhabitats may depend on predator abundances, predator size and body mass and predator feeding behavior. The current project aims to investigate the dynamics of predator-prey interactions in forest microhabitats by studying potential predator species and the ecological role of oribatid mites as prey and their potential microhabitat-specific functional trait composition against predation. In feeding experiments oribatid mite species found on tree bark, grass sods, litter, dead wood, mosses, and lichens will be confronted with predatory arthropods with different compositions of predatory adaptations (e.g. small/large size, biting/sucking, foraging strategies). Predators will be characterized by their body mass, size, the functional morphology of their mouthparts (feeding behavior) and oribatid mites will be characterized by their morphological defensive traits and their defensive secretions. Furthermore, chemical defense will be manipulated prior to feeding experiments, i.e. specimens will be chemically disarmed and their defense success will be compared to that of chemically defended specimens. Additionally, the degree of sclerotization of the model organism Archegozetes longisetosus will be modified by culturing specimens on wheatgrass with different amounts of the amino acid tyrosine/phenylalanine which are essentially involved in sclerotization.

捕食作用是影响物种间相互作用的重要因素，并可能影响森林小生境中物种的分布。捕食的功能反应是由多种因素（搜索和处理时间，大小和体重，捕食者和猎物的人口密度）。然而，许多被捕食物种已经进化出显著影响捕食成功的防御特征。森林微生境中土壤节肢动物的捕食-被捕食相互作用是复杂的，在自然界中很难监测，由于涉及的物种的小尺寸和微生境的复杂性。甲螨是研究森林微生境中捕食者-被捕食者相互作用的结构和动态的理想模型，因为（a）它们非常古老，是陆地上最早的动物之一，（B）它们普遍存在于树皮、草地、凋落物、枯木中，苔藓和地衣，由于其高丰度，可能在森林食物网中作为被捕食生物发挥重要作用，以及（c）它们进化出了几种有效的捕食者防御机制，因此被假设以某种方式生活在一个功能性的“无敌人空间”中。甲螨成虫的捕食防御机制包括形态学和化学两个方面。形态适应是永久性的，包括角质层的强烈硬化，ptychoidy和pteromorphes。化学防御是一种基于芳香族化合物、萜烯、碳氢化合物、生物碱和生氰化合物的复杂混合物的分泌的动力学机制。甲螨物种的分布，无论是形态和/或化学防御在不同的森林微生境可能取决于捕食者丰度，捕食者的大小和体重和捕食者的摄食行为。本项目旨在通过研究潜在的捕食者物种和甲螨作为猎物的生态作用及其潜在的微生境特异性功能特征组成来调查森林微生境中捕食者-猎物相互作用的动态。在饲养实验中，在树皮、草皮、枯枝落叶、枯木、苔藓和地衣上发现的甲螨物种将面临具有不同组成的捕食性适应（例如，小/大尺寸、咬/吸、觅食策略）的捕食性节肢动物。捕食者的特征是他们的体重，大小，他们的口器功能形态（摄食行为）和甲螨的特征是他们的形态防御特征和防御分泌物。此外，在喂食实验之前，将操纵化学防御，即样品将被化学解除武装，并且将它们的防御成功与化学防御样品的防御成功进行比较。此外，模式生物Archegozetes longisetosus的硬化程度将通过在具有不同量的氨基酸酪氨酸/苯丙氨酸的冰草上培养标本来改变，所述氨基酸酪氨酸/苯丙氨酸基本上参与硬化。