Invertebrates as housekeepers and bodyguards: exploring the ecology of terrestrial and freshwater cleaning and defensive symbioses.

无脊椎动物作为管家和保镖：探索陆地和淡水清洁与防御共生的生态。

• 批准号: RGPIN-2019-04427
• 负责人: Proctor, Heather
• 金额: $ 3.42万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=689510
• 关键词: Invertebrates; housekeepers; bodyguards; exploring; ecology

In cleaning and defensive symbioses, smaller-bodied species remove debris and/or parasites from larger-bodied host species. The nature of these relationships can vary from helpful to the host (= mutualism) to neutral or even detrimental (= parasitism). My lab's research program will focus on three widespread but understudied cleaning/defensive mutualisms: feather mites and birds, branchiobdellid worms and crayfish, and Chaetogaster worms and snails.***(1) Does symbiont body size and location on the host influence efficacy of cleaning mutualisms? Feather mites include 2600 described species that live on and in the feathers and skin of birds. Those that live on flight feathers have long been suspected to be non-parasitic. Recently we have shown via gut-content analysis that the relationship may be mutualistic, with the mites serving as tiny cleaners that eat potentially dangerous microbes on the feathers of their hosts. My lab will examine this relationship at a fine scale to assess how mite distribution among flight feathers affects and is influenced by the distribution of potential food sources among and within feathers. We will also assess how size of mites affects their location on feathers and limits the food items they can eat. ***(2) Can symbionts aid range-expansion of their hosts? Branchiobdellid worms live on the bodies of crayfish and can act as cleaning mutualists or parasites, depending on species and population density. Until recently, branchiobdellids were absent from Alberta, where the single species of native crayfish was historically restricted to the small Beaver River drainage in northeastern Alberta. Since 1991, the crayfish has greatly expanded its range in Alberta. The original Beaver River population still lacks crayfish worms, but in the naturally invaded parts of the new range, the crayfish have brought along their symbiotic worms. Could the presence of worms have aided natural upstream expansion of crayfish into Alberta? We will manipulate worm loads to assess how they affect host fitness, including in newly colonized water bodies.***(3) What shifts symbioses from good to bad for the host? The tiny worm Chaetogaster limnaei is unusual in being a symbiont of freshwater snails. Typically, worms live on the outer surface of the snail where they consume material stirred up by host movement. There are many reports of C. limnaei eating larvae of parasitic flatworms. This may protect their hosts from infection. Other studies suggest that snails suffer when C. limnaei is present. We will investigate ecological relationships between C. limnaei and their snail hosts to determine whether worms consistently act as defensive mutualists, or if this is dependent on host species, Chaetogaster number and genotype, or species of parasitic flatworm.***Importance: What we learn will help researchers to understand how cleaning symbionts influence the health and ecological success of birds and freshwater animals.

在清洁和防御共生体中，较小的物种从较大的宿主物种中清除碎片和/或寄生虫。这些关系的性质可以从对宿主有益（=互利共生）到中性甚至有害（=寄生）。我的实验室的研究计划将集中在三个广泛但研究不足的清洁/防御互惠关系：羽螨和鸟类，鳃蛭蠕虫和小龙虾，以及毛腹虫和蜗牛。(1)共生体的大小和在宿主上的位置是否影响清洁互惠的功效？羽毛螨包括2600种描述的物种，生活在鸟类的羽毛和皮肤上。长期以来，人们一直怀疑那些以飞行羽毛为生的鸟类不是寄生虫。最近，我们通过肠道内容物分析表明，这种关系可能是互利的，螨类充当微小的清洁剂，吃掉宿主羽毛上潜在的危险微生物。我的实验室将在一个精细的尺度上研究这种关系，以评估螨在飞羽中的分布如何影响羽毛之间和羽毛内潜在食物来源的分布。我们还将评估螨的大小如何影响它们在羽毛上的位置，并限制它们可以吃的食物。* （2）共生体可以帮助宿主的范围扩展吗？鳃蛭蠕虫生活在小龙虾的身体上，根据物种和种群密度，可以作为清洁互惠者或寄生虫。直到最近，阿尔伯塔还没有鳃蛭类，在那里，单一种类的本地小龙虾历史上仅限于阿尔伯塔东北部的小海狸河流域。自1991年以来，小龙虾在阿尔伯塔的范围大大扩大。最初的海狸河种群仍然缺乏小龙虾蠕虫，但在新范围的自然入侵部分，小龙虾带来了沿着他们的共生蠕虫。蠕虫的存在是否有助于小龙虾向阿尔伯塔的自然上游扩张？我们将操纵蠕虫负载来评估它们如何影响宿主适应度，包括在新定居的水体中。* (3)是什么让共生体从对宿主有利变成对宿主有害？微小的蠕虫Chaetogaster limnaei是淡水蜗牛的共生体。通常，蠕虫生活在蜗牛的外表面，在那里它们消耗由宿主移动引起的物质。有许多关于C.以寄生扁形虫幼虫为食的淡水鱼。这可以保护宿主免受感染。其他研究表明，当C。Limnaei存在。我们将探讨C. limnaei和它们的蜗牛宿主，以确定蠕虫是否始终作为防御互惠者，或者这是否取决于宿主物种，Chaetogaster数量和基因型，或寄生扁形虫的物种。重要性：我们所了解的将有助于研究人员了解清洁共生体如何影响鸟类和淡水动物的健康和生态成功。