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Hietaranta E, Juottonen H, Kytöviita MM. Honeybees affect floral microbiome composition in a central food source for wild pollinators in boreal ecosystems. Oecologia 2023; 201:59-72. [PMID: 36434466 DOI: 10.1007/s00442-022-05285-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 11/07/2022] [Indexed: 11/26/2022]
Abstract
Basic knowledge on dispersal of microbes in pollinator networks is essential for plant, insect, and microbial ecology. Thorough understanding of the ecological consequences of honeybee farming on these complex plant-pollinator-microbe interactions is a prerequisite for sustainable honeybee keeping. Most research on plant-pollinator-microbe interactions have focused on temperate agricultural systems. Therefore, information on a wild plant that is a seasonal bottleneck for pollinators in cold climate such as Salix phylicifolia is of specific importance. We investigated how floral visitation by insects influences the community structure of bacteria and fungi in Salix phylicifolia inflorescences under natural conditions. Insect visitors were experimentally excluded with net bags. We analyzed the microbiome and measured pollen removal in open and bagged inflorescences in sites where honeybees were foraging and in sites without honeybees. Site and plant individual explained most of the variation in floral microbial communities. Insect visitation and honeybees had a smaller but significant effect on the community composition of microbes. Honeybees had a specific effect on the inflorescence microbiome and, e.g., increased the relative abundance of operational taxonomic units (OTUs) from the bacterial order Lactobacillales. Site had a significant effect on the amount of pollen removed from inflorescences but this was not due to honeybees. Insect visitors increased bacterial and especially fungal OTU richness in the inflorescences. Pollinator visits explained 38% variation in fungal richness, but only 10% in bacterial richness. Our work shows that honeybee farming affects the floral microbiome in a wild plant in rural boreal ecosystems.
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Affiliation(s)
- Elsi Hietaranta
- Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.
| | - Heli Juottonen
- Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Minna-Maarit Kytöviita
- Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
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2
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Soininen JOS, Kytöviita M. Geranium sylvaticum increases pollination probability by sexually dimorphic flowers. Ecol Evol 2022; 12:e9670. [PMID: 36590340 PMCID: PMC9797467 DOI: 10.1002/ece3.9670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 12/10/2022] [Indexed: 12/29/2022] Open
Abstract
Sexual dimorphism is expressed as different morphologies between the sexes of a species. Dimorphism is pronounced in gynodioecious populations which consist of female and hermaphrodite individuals. The small size of female flowers in gynodioecious species is often explained by resource re-allocation to seed production instead of large flowers. However, pollinator attraction is critical to female fitness, and factors other than resource savings are needed to explain the small size of female flowers. We hypothesized that the floral size dimorphism in the perennial gynodioecious Geranium sylvaticum (L.) is adaptive in terms of pollination. To test this "pollination hypothesis," we video recorded the small female and large hermaphrodite G. sylvaticum flowers. We parameterized floral visitor behavior when visiting a flower and calculated pollination probabilities by a floral visitor as the probability of touching anther and stigma with the same body part. Pollination probability differed in terms of flower sex and pollinator species. Bumblebees had the highest pollination probability. The small female flowers were more likely to receive pollen via several pollinator groups than the large hermaphrodite flowers. The pollen display of hermaphrodites matched poorly with the stigma display of hermaphrodites, but well with that of females. Although the small size of female flowers is commonly explained by resource re-allocation, we show that sexual dimorphism in flower size may increase the main reproductive functions of the females and hermaphrodites. Dimorphism increases pollination probability in females and fathering probability of the hermaphrodites likely driving G. sylvaticum populations towards dioecy.
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Affiliation(s)
- Jaakko O. S. Soininen
- Department of Biological and Environmental Sciences, Faculty of Mathematics and ScienceUniversity of JyväskyläJyväskyläFinland
| | - Minna‐Maarit Kytöviita
- Department of Biological and Environmental Sciences, Faculty of Mathematics and ScienceUniversity of JyväskyläJyväskyläFinland
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Toji T, Itino T. Differences in the flower visitor behaviour on female and hermaphroditic flowers of Cimicifuga simplex. J NAT HIST 2021. [DOI: 10.1080/00222933.2021.1946611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Tsubasa Toji
- Department of Science and Technology, Graduate School of Medicine, Science and Technology, Shinshu University, Nagano, Japan
| | - Takao Itino
- Faculty of Science, Shinshu University, Nagano, Japan
- Institute of Mountain Science, Shinshu University, Nagano, Japan
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Konarska A, Masierowska M. Structure of floral nectaries and female-biased nectar production in protandrous species Geranium macrorrhizum and Geranium phaeum. PROTOPLASMA 2020; 257:501-523. [PMID: 31792604 DOI: 10.1007/s00709-019-01454-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/24/2019] [Indexed: 05/12/2023]
Abstract
Nectar is a major floral reward offered to pollinators by plants. In dichogamous plant species, differences in nectar production across sexual phases often occur, but both the male- and female-phase flowers have to attract pollinators to achieve effective pollination. Nectar-producing structures, i.e. floral nectaries, are a key component of floral organisation and architecture, and the knowledge of their structure and function contributes to better understanding of the plant-pollinator interactions. In the present study, we investigated the morphology and structure of nectaries and the nectar production pattern in two protandrous species Geranium macrorrhizum and G. phaeum. The flowers of the studied species have been shown to exhibit varied availability of nectar for insect visitors. Their nectaries differ in the shape, size and thickness. The other differences include the localisation of the stomatal field, the size and number of nectarostomata, the presence of non-glandular and glandular trichomes, the presence of tannin idioblasts, the mode of secretion and the occurrence of plastids functioning probably as autophagosomes and autolysosomes, whose presence in nectary cells has been described for the first time. The flowers of the studied species started nectar secretion in the non-receptive phase before pollen presentation and nectar was produced throughout both sexual phases. The nectar production was gender biased towards the female phase in the nectar amount, nectar sugar concentration and total sugar secreted in the nectar. We postulate that the nectar production patterns in G. phaeum and G. macrorrhizum might have evolved as a response to pollinators' pressure.
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Affiliation(s)
- Agata Konarska
- Department of Botany and Plant Physiology, University of Life Sciences in Lublin, Akademicka 15, 20-950, Lublin, Poland
| | - Marzena Masierowska
- Department of Botany and Plant Physiology, University of Life Sciences in Lublin, Akademicka 15, 20-950, Lublin, Poland.
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Jacquemart AL, Buyens C, Hérent MF, Quetin-Leclercq J, Lognay G, Hance T, Quinet M. Male flowers of Aconitum compensate for toxic pollen with increased floral signals and rewards for pollinators. Sci Rep 2019; 9:16498. [PMID: 31712605 PMCID: PMC6848206 DOI: 10.1038/s41598-019-53355-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/26/2019] [Indexed: 01/25/2023] Open
Abstract
Many plants require animal pollinators for successful reproduction; these plants provide pollinator resources in pollen and nectar (rewards) and attract pollinators by specific cues (signals). In a seeming contradiction, some plants produce toxins such as alkaloids in their pollen and nectar, protecting their resources from ineffective pollinators. We investigated signals and rewards in the toxic, protandrous bee-pollinated plant Aconitum napellus, hypothesizing that male-phase flower reproductive success is pollinator-limited, which should favour higher levels of signals (odours) and rewards (nectar and pollen) compared with female-phase flowers. Furthermore, we expected insect visitors to forage only for nectar, due to the toxicity of pollen. We demonstrated that male-phase flowers emitted more volatile molecules and produced higher volumes of nectar than female-phase flowers. Alkaloids in pollen functioned as chemical defences, and were more diverse and more concentrated compared to the alkaloids in nectar. Visitors actively collected little pollen for larval food but consumed more of the less-toxic nectar. Toxic pollen remaining on the bee bodies promoted pollen transfer efficiency, facilitating pollination.
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Affiliation(s)
- A-L Jacquemart
- Earth and Life Institute- Agronomy - Université catholique de Louvain, Croix du Sud 2, Box L7.05.14, B-1348, Louvain-la-Neuve, Belgium.
| | - C Buyens
- Earth and Life Institute- Agronomy - Université catholique de Louvain, Croix du Sud 2, Box L7.05.14, B-1348, Louvain-la-Neuve, Belgium
| | - M-F Hérent
- Louvain Drug Research Institute, Pharmacognosy Research Group - Université catholique de Louvain, Avenue E. Mounier, 72, B-1200, Brussels, Belgium
| | - J Quetin-Leclercq
- Louvain Drug Research Institute, Pharmacognosy Research Group - Université catholique de Louvain, Avenue E. Mounier, 72, B-1200, Brussels, Belgium
| | - G Lognay
- Analytical Chemistry, Gembloux Agro-Bio Tech, Université de Liège, Passage des Déportés 2, B-5030, Gembloux, Belgium
| | - T Hance
- Earth and Life Institute - Biodiversity - Université catholique de Louvain, Croix du Sud 4, Box L7.07.04, B-1348, Louvain-la-Neuve, Belgium
| | - M Quinet
- Earth and Life Institute- Agronomy - Université catholique de Louvain, Croix du Sud 2, Box L7.05.14, B-1348, Louvain-la-Neuve, Belgium
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Dunlap AS, Austin MW, Figueiredo A. Components of change and the evolution of learning in theory and experiment. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2018.05.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Varga S, Kytöviita MM. Sexes in gynodioecious Geranium sylvaticum do not differ in their isotopic signature or photosynthetic capacity. PLANT BIOLOGY (STUTTGART, GERMANY) 2017; 19:896-903. [PMID: 28742938 DOI: 10.1111/plb.12606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/20/2017] [Indexed: 06/07/2023]
Abstract
In gynodioecious plants, females are expected to produce more or better seeds than hermaphrodites in order to be maintained within the same population. Even though rarely measured, higher seed production can be achieved through differences in physiology. In this work, we measured sexual dimorphism in several physiological traits in the gynodioecious plant Geranium sylvaticum. Photosynthetic rate, stomatal conductance, transpiration rate, WUE and isotopic signatures were measured in plants growing in two habitats differing in light availability. Females have been reported to produce more seeds than hermaphrodites. However, we did not observe any significant difference in seed output between the sexes in these experimental populations. Similarly, the sexes did not differ in any physiological trait measured. Seed production was strongly limited by light availability. Likewise, differences between plants growing in full light versus low light were detected in most physiological parameters measured. Our results show that the sexes in G. sylvaticum do not show any evidence of sexual dimorphism in physiology, which concurred with a lack of sexual differences in seed output.
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Affiliation(s)
- S Varga
- School of Life Sciences, Joseph Banks Laboratories, Green Lane, University of Lincoln, Lincoln, UK
| | - M-M Kytöviita
- Department of Biological and Environmental Science, University of Jyvaskyla, Jyvaskyla, Finland
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Tuominen A, Salminen JP. Hydrolyzable Tannins, Flavonol Glycosides, and Phenolic Acids Show Seasonal and Ontogenic Variation in Geranium sylvaticum. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:6387-6403. [PMID: 28525277 DOI: 10.1021/acs.jafc.7b00918] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The seasonal variation of polyphenols in the aboveground organs and roots of Geranium sylvaticum in four populations was studied using UPLC-DAD-ESI-QqQ-MS/MS. The content of the main compound, geraniin, was highest (16% of dry weight) in the basal leaves after the flowering period but stayed rather constant throughout the growing season. Compound-specific mass spectrometric methods revealed the different seasonal patterns in minor polyphenols. Maximum contents of galloylglucoses and flavonol glycosides were detected in the small leaves in May, whereas the contents of further modified ellagitannins, such as ascorgeraniin and chebulagic acid, increased during the growing season. In flower organs, the polyphenol contents differed significantly between ontogenic phases so that maximum amounts were typically found in the bud phase, except in pistils the amount of gallotannins increased significantly in the fruit phase. These results can be used in evaluating the role of polyphenols in plant-herbivore interactions or in planning the best collection times of G. sylvaticum for compound isolation purposes.
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Affiliation(s)
- Anu Tuominen
- Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku , FI-20500 Turku, Finland
| | - Juha-Pekka Salminen
- Laboratory of Organic Chemistry and Chemical Biology, Department of Chemistry, University of Turku , FI-20500 Turku, Finland
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Varga S, Soulsbury CD. Sexually-trimorphic interactions with colour polymorphism determine nectar quality in a herbaceous perennial. Sci Rep 2017; 7:45838. [PMID: 28374829 PMCID: PMC5379179 DOI: 10.1038/srep45838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 03/06/2017] [Indexed: 11/09/2022] Open
Abstract
Amongst gynodioecious plant breeding systems, there can exist intermediate morphs with a reduction in their male function (i.e. reduced number of functional anthers). Along with this sexual trimorphism, plants can also show floral colour polymorphism. Such intricate mixtures of phenotypes within a species may have complex effects on floral rewards. Floral rewards are known to vary between sexually dimorphic species and to a lesser extent between colour morphs. However, the interactive effect of sexual trimorphism and colour polymorphism is unexplored. We measured nectar's sugar content in the sexually trimorphic Geranium sylvaticum, a gynodioecious plant with a light/dark floral polymorphism. We found that nectar reward differed across genders and colour morphs. Results were not however consistent within the three genders; dark female and hermaphrodite flowers had higher sugar content than light morphs, whereas intermediate flowers did not. As expected, females and hermaphrodites had different nectar reward, with intermediate morphs being midway between the other genders. In intermediates, the sugar content was not related to the number of functional stamens. We show for the first time the existence of sex-specific differences between flower gender and colour morphs in nectar rewards. Our results demonstrate the importance of considering multiple and conflicting selection pressures to explain rewards.
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Affiliation(s)
- Sandra Varga
- School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Lincoln LN6 7TS, UK
| | - Carl D. Soulsbury
- School of Life Sciences, University of Lincoln, Joseph Banks Laboratories, Lincoln LN6 7TS, UK
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Davis SL, Dudle DA, Nawrocki JR, Freestone LM, Konieczny P, Tobin MB, Britton MM. Sexual dimorphism of staminate- and pistillate-phase flowers of Saponaria officinalis (bouncing bet) affects pollinator behavior and seed set. PLoS One 2014; 9:e93615. [PMID: 24690875 PMCID: PMC3972141 DOI: 10.1371/journal.pone.0093615] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 03/07/2014] [Indexed: 01/25/2023] Open
Abstract
The sequential separation of male and female function in flowers of dichogamous species allows for the evolution of differing morphologies that maximize fitness through seed siring and seed set. We examined staminate- and pistillate-phase flowers of protandrous Saponaria officinalis for dimorphism in floral traits and their effects on pollinator attraction and seed set. Pistillate-phase flowers have larger petals, greater mass, and are pinker in color, but due to a shape change, pistillate-phase flowers have smaller corolla diameters than staminate-phase flowers. There was no difference in nectar volume or sugar content one day after anthesis, and minimal evidence for UV nectar guide patterns in staminate- and pistillate-phase flowers. When presented with choice arrays, pollinators discriminated against pistillate-phase flowers based on their pink color. Finally, in an experimental garden, in 2012 there was a negative correlation between seed set of an open-pollinated, emasculated flower and pinkness (as measured by reflectance spectrometry) of a pistillate-phase flower on the same plant in plots covered with shade cloth. In 2013, clones of genotypes chosen from the 2012 plants that produced pinker flowers had lower seed set than those from genotypes with paler flowers. Lower seed set of pink genotypes was found in open-pollinated and hand-pollinated flowers, indicating the lower seed set might be due to other differences between pink and pale genotypes in addition to pollinator discrimination against pink flowers. In conclusion, staminate- and pistillate-phase flowers of S. officinalis are dimorphic in shape and color. Pollinators discriminate among flowers based on these differences, and individuals whose pistillate-phase flowers are most different in color from their staminate-phase flowers make fewer seeds. We suggest morphological studies of the two sex phases in dichogamous, hermaphroditic species can contribute to understanding the evolution of sexual dimorphism in plants without the confounding effects of genetic differences between separate male and female individuals.
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Affiliation(s)
- Sandra L. Davis
- University of Indianapolis, Department of Biology, Indianapolis, Indiana, United States of America
- * E-mail:
| | - Dana A. Dudle
- DePauw University, Department of Biology, Greencastle, Indiana, United States of America
| | - Jenna R. Nawrocki
- University of Indianapolis, Department of Biology, Indianapolis, Indiana, United States of America
| | - Leah M. Freestone
- DePauw University, Department of Biology, Greencastle, Indiana, United States of America
| | - Peter Konieczny
- DePauw University, Department of Biology, Greencastle, Indiana, United States of America
| | - Michael B. Tobin
- DePauw University, Department of Biology, Greencastle, Indiana, United States of America
| | - Michael M. Britton
- DePauw University, Department of Biology, Greencastle, Indiana, United States of America
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