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，体型较小的物种从体型较大的宿主物种中清除碎片和/或寄生虫。这些关系的性质可能不同，从对宿主有益(=互惠)到中立甚至有害(=寄生)。我的实验室的研究计划将重点放在三个广泛但未被研究的清洁/防御互惠关系上：羽毛螨类和鸟类，鳃形目蠕虫和小龙虾，以及毛壳虫和蜗牛。(1)共生菌在寄主上的大小和位置是否会影响清洁互惠的效果？羽螨包括2600种所描述的生活在鸟类羽毛和皮肤上的物种。长期以来，人们一直怀疑那些以飞行羽毛为生的动物不是寄生虫。最近，我们通过肠道内容物分析表明，这种关系可能是互惠互利的，蠕虫充当微小的清洁工，吃掉宿主羽毛上潜在危险的微生物。我的实验室将在一个精细的范围内研究这种关系，以评估尘螨在飞行羽毛中的分布如何影响以及受到潜在食物来源在羽毛之间和羽毛内的分布的影响。我们还将评估螨类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)共生体能帮助扩大宿主的活动范围吗？Branchiobdellid蠕虫生活在小龙虾身上，根据物种和种群密度的不同，它们可以充当清洁互助者或寄生虫的角色。直到最近，小龙虾在艾伯塔省还没有出现，那里的本土小龙虾在历史上一直被限制在艾伯塔省东北部的小比弗河流域。自1991年以来，小龙虾在艾伯塔省的活动范围大大扩大。原来的比弗河种群仍然缺乏小龙虾蠕虫，但在新范围内自然入侵的部分，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艾伯塔省上游的自然扩张？我们将操纵蠕虫的负载来评估它们如何影响宿主的健康，包括在新定居的水体中。(3)对宿主来说，是什么将共生从好转到坏？微小的毛毛虫是淡水蜗牛的共生体，这一点很不寻常。通常情况下，蠕虫生活在蜗牛的外表面，在那里它们消耗由宿主运动激起的物质。已有许多关于利姆奈吸食寄生扁虫幼虫的报道。这可能会保护它们的宿主免受感染。其他研究表明，当有利姆奈伊线虫存在时，蜗牛会受到影响。我们将调查线虫和它们的蜗牛宿主之间的生态关系，以确定蠕虫是否始终扮演着防御性互助者的角色，或者这是否依赖于寄生扁虫的宿主种类、Chaetogaster数量和基因，或者寄生扁虫的种类。重要性：我们所了解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。