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.

在清洁和防御共生中，较小体型的物种会从较大体型的宿主物种中清除碎片和/或寄生虫。这些关系的性质可能有所不同，从对宿主有帮助（=互利共生）到中性甚至有害（=寄生）。我实验室的研究计划将重点关注三种广泛但尚未得到充分研究的清洁/防御互利共生：羽螨和鸟类、鳃类蠕虫和小龙虾、以及毛壳虫和蜗牛。 （1）共生体的大小和在宿主上的位置是否影响清洁互利共生的功效？羽毛螨包括 2600 种描述的物种，它们生活在鸟类的羽毛和皮肤上和内部。长期以来，人们一直怀疑那些以飞羽为生的鸟类是非寄生性的。最近，我们通过肠道内容物分析表明，这种关系可能是互利共生的，螨虫充当微小的清洁工，吃掉宿主羽毛上潜在危险的微生物。我的实验室将在精细范围内研究这种关系，以评估飞羽之间的螨分布如何影响羽毛之间和内部潜在食物来源的分布以及如何受到羽毛内部潜在食物来源分布的影响。我们还将评估螨虫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) 共生体能帮助宿主扩大活动范围吗？鳃类蠕虫生活在小龙虾的身体上，可以作为清洁互利共生者或寄生虫，具体取决于物种和种群密度。直到最近，阿尔伯塔省还没有出现鳃螯虾，当地的单一品种小龙虾历史上仅限于阿尔伯塔省东北部的小海狸河流域。自 1991 年以来，小龙虾在艾伯塔省的分布范围大大扩大。原来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，小龙虾已经带来了它们的共生蠕虫。蠕虫的存在是否有助于小龙虾向上游自然扩张到艾伯塔省？我们将操纵蠕虫负载来评估它们如何影响宿主的健康状况，包括在新殖民的水体中。 (3) 是什么使共生体从对宿主有利变为不利？微小的毛毛虫（Chaetogaster limnaei）的不同寻常之处在于它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运动搅动的物质。有许多关于 C. limnaei 吃寄生扁虫幼虫的报道。这可以保护它们的宿主免受感染。其他研究表明，当 C. limnaei 存在时，蜗牛会受到影响。我们将调查 C. limnaei 与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互利共生者，或者这是否取决于宿主物种、毛壳虫数量和基因型或寄生扁虫的物种。重要性：我们所学到的知识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。