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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=744813
• 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.

在清洁和防御性共生中，较小的物种从大型宿主物种中清除了碎屑和/或寄生虫。这些关系的性质可能从对宿主（=互助）到中立甚至有害（寄生虫）的性质不等。我的实验室的研究计划将集中于三个广泛但研究的清洁/防御性互助：羽毛螨和鸟类，branchiobdellid蠕虫和小龙虾，以及chaetogaster蠕虫和蜗牛。 （1）共生体大小和宿主的位置会影响清洁互助的功效吗？羽毛螨包括生活在鸟类和皮肤上的2600种描述的物种。长期以来一直怀疑生活在飞行羽毛上的人是非寄生虫。最近，我们通过肠内分析表明，这种关系可能是相互主义的，螨虫用作微小的清洁剂，它们在宿主的羽毛上吃了潜在的危险微生物。我的实验室将以良好的规模检查这种关系，以评估飞行羽毛之间的螨虫分布如何影响，并受到羽毛之间和内部潜在食物来源的分布的影响。我们还将评估螨虫的大小如何影响其在羽毛上的位置，并限制他们可以吃的食物。 （2）共生体可以帮助其宿主的范围扩展吗？ Branchiobdellid蠕虫生活在小龙虾的体内，可以作为清洁的共同主义者或寄生虫，具体取决于物种和种群密度。直到最近，阿尔伯塔省仍未出现过分支机构，那里的单一物种小龙虾历史上仅限于艾伯塔省东北部的小海狸河流排水系统。自1991年以来，小龙虾大大扩大了其在艾伯塔省的范围。最初的海狸河种群仍然缺少小龙虾蠕虫，但是在新系列的自然入侵部分中，小龙虾带来了它们的共生蠕虫。蠕虫的存在是否可以帮助小龙虾上游膨胀到艾伯塔省？我们将操纵蠕虫负载，以评估它们如何影响宿主健身，包括在新定植的水体中。 （3）什么将共生物从对主机的好处转变为坏？小蠕虫Chaetogaster limnaei是成为淡水蜗牛的共生体。通常，蠕虫活在蜗牛的外表面上，它们消耗的材料被宿主运动搅动。有许多报道说，林奈梭菌吃了寄生虫的幼虫。这可以保护他们的宿主免受感染。其他研究表明，当存在limnaei时，蜗牛会遭受痛苦。我们将研究Limnaei及其蜗牛宿主之间的生态关系，以确定蠕虫是否始终充当防御性共同主义者，或者这是否取决于宿主物种，Chaetogaster数量和基因型或寄生虫的物种。重要性：我们学到的将帮助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。