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Floral nectar is prone to colonization by nectar-adapted yeasts and bacteria via air-, rain-, and animal-mediated dispersal. Upon colonization, microbes can modify nectar chemical constituents that are plant-provisioned or impart their own through secretion of metabolic by-products or antibiotics into the nectar environment. Such modifications can have consequences for pollinator perception of nectar quality, as microbial metabolism can leave a distinct imprint on olfactory and gustatory cues that inform foraging decisions. Furthermore, direct interactions between pollinators and nectar microbes, as well as consumption of modified nectar, have the potential to affect pollinator health both positively and negatively. Here, we discuss and integrate recent findings from research on plant–microbe–pollinator interactions and their consequences for pollinator health. We then explore future avenues of research that could shed light on the myriad ways in which nectar microbes can affect pollinator health, including the taxonomic diversity of vertebrate and invertebrate pollinators that rely on this reward. This article is part of the theme issue ‘Natural processes influencing pollinator health: from chemistry to landscapes’.
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The dispersal of microbes among and within flowers by butterflies
Abstract Floral microbes, including bacteria and fungi, alter nectar quality, thus changing pollinator visitation. Conversely, pollinator visitation can change the floral microbial community.Most studies on dispersal of floral microbes have focused on bees, ants or hummingbirds, yet Lepidoptera are important pollinators.We asked (a) where are microbes present on the butterfly body, (b) do butterflies transfer microbes while foraging, and (c) how does butterfly foraging affect microbial abundance on different floret structures.The tarsi and proboscis had significantly more microbes than the thorax in wild‐caughtGlaucopsyche lygdamus(Lepidoptera: Lycaenidae) andSpeyeria mormonia(Lepidoptera: Nymphalidae).Glaucopsyche lygdamus, a smaller‐bodied species, had fewer microbes thanS. mormonia.As a marker for microbes, we used a bacterium (Rhodococcus fascians,near NCBI Y11196) isolated from aS. mormoniathat was foraging for nectar, and examined its dispersal byG. lygdamusandS. mormoniavisiting florets ofPyrrocoma crocea(Asteraceae). Microbial dispersal among florets correlated positively with bacterial abundance in the donor floret. Dispersal also depended on butterfly species, age, and bacterial load carried by the butterfly.Recipient florets had less bacteria than donor florets. The nectaries had more bacteria than the anthers or the stigmas, while anthers and stigmas did not differ from each other. There was no differential transmission among floral organs.Lepidoptera thus act as vectors of floral microbes. Including Lepidoptera is thus crucial to an understanding of plant–pollinator–microbe interactions. Future studies should consider the role of vectored microbes in lepidopteran ecology and fitness.
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- Award ID(s):
- 1755522
- PAR ID:
- 10514925
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Ecological Entomology
- Volume:
- 48
- Issue:
- 4
- ISSN:
- 0307-6946
- Page Range / eLocation ID:
- 458 to 465
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1111/een.13239
