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Štenc J, Janošík L, Matoušková E, Hadrava J, Mikát M, Janovský Z. Pollinator visitation closely tracks diurnal patterns in pollen release. AMERICAN JOURNAL OF BOTANY 2023:e16179. [PMID: 37200483 DOI: 10.1002/ajb2.16179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 05/20/2023]
Abstract
PREMISE Animal-pollinated plants face a high risk of pollen loss during its transfer. To limit the negative effect of pollen losses by pollen consumption and heterospecific transfer, plant species may adjust and stratify their pollen availability during the day (i.e., "schedule" their pollen presentation) and attract pollinators in specific time frames. METHODS We investigated diurnal patterns of pollen availability and pollinator visitation in three coflowering plant species: Succisa pratensis with open flowers and accessible pollen, pollinated mainly by pollen-feeding hoverflies; Centaurea jacea with open flowers and less accessible pollen, pollinated mainly by pollen-collecting bees; and Trifolium hybridum with closed flowers and pollen accessible only after the active opening of the flower, pollinated exclusively by bees. RESULTS The three plant species differed in the peak pollen availability, tracked by the visitation activity of their pollinators. Succisa pratensis released all pollen in the morning, while pollinator activity was still low and peaked with a slight delay. In contrast, C. jacea and T. hybridum had distinct pollen presentation schedules, peaking in the early afternoon. The pollinator visitation to both of these species closely matched their pollen availability. CONCLUSIONS Stratifying pollen availability to pollinators during the day may be one of several mechanisms that allow coflowering plants to share their pollinators and decrease the probability of heterospecific pollen transfer.
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Affiliation(s)
- Jakub Štenc
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 41, Prague, Czech Republic
| | - Lukáš Janošík
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 41, Prague, Czech Republic
| | - Eva Matoušková
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-128 41, Prague, Czech Republic
| | - Jiří Hadrava
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-128 41, Prague, Czech Republic
| | - Michael Mikát
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, CZ-128 41, Prague, Czech Republic
- Department of Biology, Faculty of Science, York University, 4700 Keele Street, 203D, M3J 1P3, Toronto, Canada
- Department of General Zoology, Faculty of Natural Sciences 1-Biosciences, Martin Luther University, Hoher Weg 8, 06100 Halle (Saale), Germany
| | - Zdeněk Janovský
- Svatý Jan t. Krsovice 1, 285 04 Uhlířské Janovice, Czech Republic
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Biella P, Akter A, Ollerton J, Tarrant S, Janeček Š, Jersáková J, Klecka J. Experimental loss of generalist plants reveals alterations in plant-pollinator interactions and a constrained flexibility of foraging. Sci Rep 2019; 9:7376. [PMID: 31089144 PMCID: PMC6517441 DOI: 10.1038/s41598-019-43553-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 04/26/2019] [Indexed: 12/04/2022] Open
Abstract
Species extinctions undermine ecosystem functioning, with the loss of a small subset of functionally important species having a disproportionate impact. However, little is known about the effects of species loss on plant-pollinator interactions. We addressed this issue in a field experiment by removing the plant species with the highest visitation frequency, then measuring the impact of plant removal on flower visitation, pollinator effectiveness and insect foraging in several sites. Our results show that total visitation decreased exponentially after removing 1-4 most visited plants, suggesting that these plants could benefit co-occurring ones by maintaining high flower visitor abundances. Although we found large variation among plant species, the redistribution of the pollinator guild affected mostly the other plants with high visitor richness. Also, the plant traits mediated the effect of removal on flower visitation; while visitation of plants which had smaller inflorescences and more sugar per flower increased after removal, flower visitors did not switch between flower shapes and visitation decreased mostly in plants visited by many morpho-species of flower visitors. Together, these results suggest that the potential adaptive foraging was constrained by flower traits. Moreover, pollinator effectiveness fluctuated but was not directly linked to changes of flower visitation. In conclusion, it seems that the loss of generalist plants alters plant-pollinator interactions by decreasing pollinator abundance with implications for pollination and insect foraging. Therefore, generalist plants have high conservation value because they sustain the complex pattern of plant-pollinator interactions.
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Affiliation(s)
- Paolo Biella
- University of South Bohemia, Faculty of Science, Department of Zoology, České Budějovice, Czech Republic.
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic.
- University of Milano-Bicocca, Department of Biotechnology and Biosciences, Milan, Italy.
| | - Asma Akter
- University of South Bohemia, Faculty of Science, Department of Zoology, České Budějovice, Czech Republic
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
| | - Jeff Ollerton
- Faculty of Arts, Science and Technology, University of Northampton, Northampton, UK
| | - Sam Tarrant
- Faculty of Arts, Science and Technology, University of Northampton, Northampton, UK
| | - Štěpán Janeček
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, Praha, CZ-12844, Czech Republic
| | - Jana Jersáková
- University of South Bohemia, Faculty of Science, Department of Ecosystems Biology, České Budějovice, Czech Republic
| | - Jan Klecka
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
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Klecka J, Hadrava J, Biella P, Akter A. Flower visitation by hoverflies (Diptera: Syrphidae) in a temperate plant-pollinator network. PeerJ 2018; 6:e6025. [PMID: 30533311 PMCID: PMC6282941 DOI: 10.7717/peerj.6025] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 10/25/2018] [Indexed: 11/20/2022] Open
Abstract
Hoverflies (Diptera: Syrphidae) are among the most important pollinators, although they attract less attention than bees. They are usually thought to be rather opportunistic flower visitors, although previous studied demonstrated that they show colour preferences and their nectar feeding is affected by morphological constraints related to flower morphology. Despite the growing appreciation of hoverflies and other non-bee insects as pollinators, there is a lack of community-wide studies of flower visitation by syrphids. The aim of this paper is to provide a detailed analysis of flower visitation patterns in a species rich community of syrphids in a Central European grassland and to evaluate how species traits shape the structure of the plant-hoverfly flower visitation network. We found that different species varied in the level of specialisation, and while some species visited a similar spectre of flowers, others partitioned resources more strongly. There was a consistent difference in both specialisation and flower preferences between three syrphid subfamilies. Eristalinae and Pipizinae were more specialised than Syrphinae. Trait-based analyses showed that relative flower visitation (i) increased with plant height, but most strongly in Eristalinae; (ii) increased with inflorescence size in small species from all three subfamilies, but was independent of inflorescence size in large species of Eristalinae and Syrphinae; and (iii) depended on flower colour, but in a subfamily-specific way. Eristalinae showed the strongest flower colour preferences for white flowers, Pipizinae visited mostly white and yellow flowers, while Syrphinae were less affected by flower colour. Exploration of the structure of the plant-hoverfly flower visitation network showed that the network was both modular and nested. We also found that there were almost no differences in specialisation and relative visitation frequency between males and females. Overall, we showed that flower visitation in syrphids was affected by phylogenetic relatedness, body size of syrphids and several plant traits.
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Affiliation(s)
- Jan Klecka
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
| | - Jiří Hadrava
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Paolo Biella
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Asma Akter
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, České Budějovice, Czech Republic
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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Santos JD, Varassin IG, Muschner VC. Effects of neighborhood on pollination and seed dispersal of a threatened palm. ACTA OECOLOGICA 2018. [DOI: 10.1016/j.actao.2018.08.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mesgaran MB, Bouhours J, Lewis MA, Cousens RD. How to be a good neighbour: Facilitation and competition between two co-flowering species. J Theor Biol 2017; 422:72-83. [PMID: 28419864 DOI: 10.1016/j.jtbi.2017.04.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 04/09/2017] [Accepted: 04/10/2017] [Indexed: 11/29/2022]
Abstract
Empirical evidence suggests that co-flowering species can facilitate each other through shared pollinators. However, the extent to which one co-flowering species can relieve pollination limitation of another while simultaneously competing for abiotic resource has rarely been examined. Using a deterministic model we explored the demographic outcome for one ("focal") species of its co-occurrence with a species that shares pollinators and competes for both pollinator visitation and abiotic resources. In this paper we showed how the overall impact can be positive or negative, depending on the balance between enhanced fertilization versus increased competition. Our model could predict the density of co-flowering species that will maximize the pollination rate of the focal species by attracting pollinators. Because that density will also give rise to competitive effects, a lower density of co-flowering species is required for optimizing the trade-off between enhanced fertilization and competition so as to give the maximum possible facilitation of reproduction in the focal species. Results were qualitatively different when we considered attractiveness of the co-flowering species, as opposed to its density, because attractiveness, unlike density, had no effect on competition for abiotic resources. Whereas unattractive neighbours would not bring in pollinators, very attractive neighbours would captivate pollinators, not sharing them with the focal species. Thus optimal benefit to the focal species came at intermediate levels of attractiveness in the co-flowering species. This intermediate level of attractiveness in co-flowering species simultaneously maximized pollination and overall facilitation of reproduction for the focal species. The likelihood of facilitation was predicted to decline with the selfing rate of the focal species, revealing an indirect cost for an inbreeding mating system. Whether a co-flowering species can be facilitative depends on the way pollinators respond to the plant density: only a Type III functional response for visitation rate can result in facilitation. Our model provided both a conceptual framework and precise quantitative measures for determining the impacts of a neighbouring co-flowering species on reproduction.
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Affiliation(s)
- Mohsen B Mesgaran
- School of BioSciences, The University of Melbourne, Victoria 3010, Australia.
| | - Juliette Bouhours
- Department of Mathematical and Statistical Sciences, University of Alberta, Alberta, T6G 2G1 Canada
| | - Mark A Lewis
- Department of Mathematical and Statistical Sciences, University of Alberta, Alberta, T6G 2G1 Canada; Department of Biological Sciences, University of Alberta, Alberta, T6G2G1, Canada
| | - Roger D Cousens
- School of BioSciences, The University of Melbourne, Victoria 3010, Australia.
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Bouhours J, Mesgaran MB, Cousens RD, Lewis MA. Neutral hybridization can overcome a strong Allee effect by improving pollination quality. THEOR ECOL-NETH 2017. [DOI: 10.1007/s12080-017-0333-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Richards TJ, Ortiz-Barrientos D. Immigrant inviability produces a strong barrier to gene flow between parapatric ecotypes of Senecio lautus. Evolution 2016; 70:1239-48. [PMID: 27159252 DOI: 10.1111/evo.12936] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 02/07/2016] [Accepted: 04/12/2016] [Indexed: 01/16/2023]
Abstract
Speciation proceeds when gene exchange is prevented between populations. Determining the different barriers preventing gene flow can therefore give insights into the factors driving and maintaining species boundaries. These reproductive barriers may result from intrinsic genetic incompatibilities between populations, from extrinsic environmental differences between populations, or a combination of both mechanisms. We investigated the potential barriers to gene exchange between three adjacent ecotypes of an Australian wildflower to determine the strength of individual barriers and the degree of overall isolation between populations. We found almost complete isolation between the three populations mainly due to premating extrinsic barriers. Intrinsic genetic barriers were weak and variable among populations. There were asymmetries in some intrinsic barriers due to the origin of cytoplasm in hybrids. Overall, these results suggest that reproductive isolation between these three populations is almost complete despite the absence of geographic barriers, and that the main drivers of this isolation are ecologically based, consistent with the mechanisms underlying ecological speciation.
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Affiliation(s)
- Thomas J Richards
- School of Biological Sciences St. Lucia, University of Queensland, QLD, Australia.
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Determinants of spatial distribution in a bee community: nesting resources, flower resources, and body size. PLoS One 2014; 9:e97255. [PMID: 24824445 PMCID: PMC4019551 DOI: 10.1371/journal.pone.0097255] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 04/16/2014] [Indexed: 11/30/2022] Open
Abstract
Understanding biodiversity distribution is a primary goal of community ecology. At a landscape scale, bee communities are affected by habitat composition, anthropogenic land use, and fragmentation. However, little information is available on local-scale spatial distribution of bee communities within habitats that are uniform at the landscape scale. We studied a bee community along with floral and nesting resources over a 32 km2 area of uninterrupted Mediterranean scrubland. Our objectives were (i) to analyze floral and nesting resource composition at the habitat scale. We ask whether these resources follow a geographical pattern across the scrubland at bee-foraging relevant distances; (ii) to analyze the distribution of bee composition across the scrubland. Bees being highly mobile organisms, we ask whether bee composition shows a homogeneous distribution or else varies spatially. If so, we ask whether this variation is irregular or follows a geographical pattern and whether bees respond primarily to flower or to nesting resources; and (iii) to establish whether body size influences the response to local resource availability and ultimately spatial distribution. We obtained 6580 specimens belonging to 98 species. Despite bee mobility and the absence of environmental barriers, our bee community shows a clear geographical pattern. This pattern is mostly attributable to heterogeneous distribution of small (<55 mg) species (with presumed smaller foraging ranges), and is mostly explained by flower resources rather than nesting substrates. Even then, a large proportion (54.8%) of spatial variability remains unexplained by flower or nesting resources. We conclude that bee communities are strongly conditioned by local effects and may exhibit spatial heterogeneity patterns at a scale as low as 500–1000 m in patches of homogeneous habitat. These results have important implications for local pollination dynamics and spatial variation of plant-pollinator networks.
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