Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal, Post Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa.
New Phytol. 2020 Dec;228(5):1662-1673. doi: 10.1111/nph.16791. Epub 2020 Aug 9.
It has been suggested that flowers of some angiosperms mimic vertebrate faeces (dung) in order to exploit insect pollinators that utilize faeces as a source of food and/or oviposition sites. We investigated a potential case of mimicry in Wurmbea elatior (Colchicaceae), a lily that exhibits a faecal odour and pattern of dark spots on the corolla. We found that W. elatior is pollinated by a broad assemblage of coprophagous flies and is dependent on pollinator visits for seed production. The flowers emit volatiles that are characteristic of vertebrate faeces, and three of these compounds - skatole, indole, and an unidentified compound - elicited electrophysiological antennal responses from flies. Artificial flowers laced with indole and skatole or skatole alone attracted the same assemblage of flies as was recorded on flowers of W. elatior. Spotted artificial flowers attracted twice as many flies as did those lacking spots. Experimental addition of indole and skatole to flowers of Wurmbea kraussii, a congener with unscented flowers pollinated by hoverflies, induced a shift to an insect visitor assemblage dominated by coprophagous flies. This study clarifies the roles of volatile emissions (particularly skatole) and visual signals in floral dung mimicry.
有人认为，一些被子植物的花模仿脊椎动物的粪便（粪便），以利用以粪便为食物和/或产卵场所的昆虫传粉者。我们调查了百合科（百合科）Wurmbea elatior 中可能存在的模仿现象，该花具有粪便气味和花瓣上有深色斑点的图案。我们发现，W. elatior 是由广泛的食粪蝇类授粉的，并且依赖于传粉者的访问来产生种子。花朵会释放出具有脊椎动物粪便特征的挥发物，其中三种化合物——粪臭素、吲哚和一种未识别的化合物——会引起蝇类的电生理触角反应。人工花朵上涂抹吲哚和粪臭素或粪臭素单独就能吸引与 W. elatior 花朵上记录到的相同的蝇类。有斑点的人工花朵比没有斑点的花朵吸引的苍蝇多两倍。向具有无气味花朵且由蝇类授粉的同属种 Wurmbea kraussii 的花朵中添加吲哚和粪臭素实验表明，昆虫访客组合会向以食粪蝇为主的组合转变。这项研究阐明了挥发物排放（特别是粪臭素）和视觉信号在花卉粪便模仿中的作用。
