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Scientific Reports Jul 2023Essential oils produced by medicinal plants possess important bioactive properties (antibacterial, antioxidant) of high value for human society. Pollination and...
Essential oils produced by medicinal plants possess important bioactive properties (antibacterial, antioxidant) of high value for human society. Pollination and herbivory can modify the chemical defences of plants and therefore they may influence the bioactivity of essential oils. However, the effect of ecological interactions on plant bioactivity has not yet been evaluated. We tested the hypothesis that cross-pollination and simulated herbivory modify the chemical composition of essential oils, improving the bioactive properties of the medicinal plant Lepechinia floribunda (Lamiaceae). Through controlled experiments, we showed that essential oils from the outcrossed plant progeny had a higher relative abundance of oxygenated terpenes and it almost doubled the bacteriostatic effect on Staphylococcus aureus, compared to inbred progeny (i.e., progeny produced in absence of pollinators). Herbivory affected negatively and positively the production of rare compounds in inbred and outcrossed plants, respectively, but its effects on bioactivity still remain unknown. We show for the first time that by mediating cross-pollination (indirect ecosystem service), pollinators can improve ecosystem services linked to the biological activity of plant's essential oils. We stress the importance of the qualitative component of pollination (self, cross); an aspect usually neglected in studies of pollination services.
Topics: Humans; Reproduction; Plants, Medicinal; Ecosystem; Pollination; Herbivory; Lamiaceae
PubMed: 37500739
DOI: 10.1038/s41598-023-39358-1 -
Frontiers in Plant Science 2023Insects are vital pollinators for angiosperms, playing a crucial role in their reproductive success and fruit production. is a perennial herbaceous vine that occurs in...
Insects are vital pollinators for angiosperms, playing a crucial role in their reproductive success and fruit production. is a perennial herbaceous vine that occurs in fragmented populations across East Asia. One notable feature of this plant is its trap flower, which employs a unique mechanism to attract, trap, retain, and release insects, ensuring effective pollination. The presence of this trap flower significantly influences the pollination system of Field surveys and pollination experiments were conducted to understand the processes and effectiveness of its pollination mechanism. It was allogamous and was pollinated by the species from Ceratopogonidae. During the insect attraction stage, 11.57% of the flowers contained insects, primarily Ceratopogonidae spp. Most Ceratopogonidae spp. concentrated in few flowers, indicating that although overall attraction might be modest, specific flowers acted as significant focal points for gathering. Trichomes effectively trapped Ceratopogonidae spp. inside flower tubes. In the retention stage, 26.16% of Ceratopogonidae spp. were loaded with pollen grains, but only 7.91% of those exited the flowers in the release stage. The sticky texture of the perianth's internal cavity posed challenges during this release, leading to adhesion and clogging of the narrow perianth tube. Consequently, a significant portion of Ceratopogonidae spp. became trapped on the perianth wall and perished. This highlights that despite the significant energy and resources invested in flower development, the perianth contributes to the low pollination effectiveness. This study revealed additive factors with negative effects on pollination, including the densely clustered distribution of its pollinators within only a few flowers, insufficient pollen loading onto pollinators, hindered release of entrapped pollinators due to the perianth adhesive surface, and a high rate of defective pollen grains in . These factors account for the observed phenomenon of low fruit set (7.7%) and contribute to the diminished rate of sexual reproduction in populations. This might lead the species to heavily rely on asexual reproduction, which could potentially lead to gene erosion within populations. The implications of these findings extend to the ecological and conservation aspects, emphasizing the need to understand and conserve the unique pollination system of .
PubMed: 37810400
DOI: 10.3389/fpls.2023.1226331 -
Oecologia Oct 2023Pollinators mediate interspecific and intraspecific plant-plant indirect interactions (competition vs. facilitation) via density-dependent processes, potentially shaping...
Pollinators mediate interspecific and intraspecific plant-plant indirect interactions (competition vs. facilitation) via density-dependent processes, potentially shaping the dynamics of plant communities. However, it is still unclear which ecological drivers regulate density-dependent patterns, including scale, pollination niches (i.e., the main pollinator functional group) and floral attractiveness to pollinators. In this study, we conducted three-year field observations in Hengduan Mountains of southwest China. By gathering data for more than 100 animal-pollinated plant species, we quantified the effect (positive vs. negative) of conspecific and heterospecific flower density on pollination at two scales: plot-level (4 m) and site-level (100-5000 m). Then, we investigated how pollination niches and floral attractiveness to pollinators (estimated here as average per-flower visitation rates) modulated density-dependent pollination interactions. Pollinator visitation depended on conspecific and heterospecific flower density, with rare plants subjected to interspecific competition at the plot-level and interspecific facilitation at the site-level. Such interspecific competition at the plot-level was stronger for plants pollinated by diverse insects, while interspecific facilitation at the site-level was stronger for bee-pollinated plants. Moreover, we also found stronger positive conspecific density-dependence for plants with lower floral attractiveness at the site-level, meaning that they become more frequently visited when abundant. Our study indicates that the role of pollination in maintaining rare plants and plant diversity depends on the balance of density-dependent processes in species-rich communities. We show here that such balance is modulated by scale, pollination niches and floral attractiveness to pollinators, indicating the context-dependency of diversity maintenance mechanisms.
Topics: Bees; Animals; Pollination; Plants; Flowers; Insecta; China
PubMed: 37823959
DOI: 10.1007/s00442-023-05461-3 -
American Journal of Botany Sep 2023Floral evolution in large clades is difficult to study not only because of the number of species involved, but also because they often are geographically widespread and...
PREMISE
Floral evolution in large clades is difficult to study not only because of the number of species involved, but also because they often are geographically widespread and include a diversity of outcrossing pollination systems. The cosmopolitan blueberry family (Ericaceae) is one such example, most notably pollinated by bees and multiple clades of nectarivorous birds.
METHODS
We combined data on floral traits, pollination ecology, and geography with a comprehensive phylogeny to examine the structuring of floral diversity across pollination systems and continents. We focused on ornithophilous systems to test the hypothesis that some Old World Ericaceae were pollinated by now-extinct hummingbirds.
RESULTS
Despite some support for floral differentiation at a continental scale, we found a large amount of variability within and among landmasses, due to both phylogenetic conservatism and parallel evolution. We found support for floral differentiation in anther and corolla traits across pollination systems, including among different ornithophilous systems. Corolla traits show inconclusive evidence that some Old World Ericaceae were pollinated by hummingbirds, while anther traits show stronger evidence. Some major shifts in floral traits are associated with changes in pollination system, but shifts within bee systems are likely also important.
CONCLUSIONS
Studying the floral evolution of large, morphologically diverse, and widespread clades is feasible. We demonstrate that continent-specific radiations have led to widespread parallel evolution of floral morphology. We show that traits outside of the perianth may hold important clues to the ecological history of lineages.
Topics: Animals; Bees; Pollination; Phylogeny; Ericaceae; Flowers; Phenotype; Birds
PubMed: 37551426
DOI: 10.1002/ajb2.16220 -
Annals of Botany May 2024The majority of the earth's land area is currently occupied by humans. Measuring how terrestrial plants reproduce in these pervasive environments is essential for...
BACKGROUND AND AIMS
The majority of the earth's land area is currently occupied by humans. Measuring how terrestrial plants reproduce in these pervasive environments is essential for understanding their long-term viability and their ability to adapt to changing environments.
METHODS
We conducted hierarchical and phylogenetically-independent meta-analyses to assess the overall effects of anthropogenic land-use changes on pollination, and male and female fitness in terrestrial plants.
KEY RESULTS
We found negative global effects of land use change (i.e., mainly habitat loss and fragmentation) on pollination and on female and male fitness of terrestrial flowering plants. Negative effects were stronger in plants with self-incompatibility (SI) systems and pollinated by invertebrates, regardless of life form and sexual expression. Pollination and female fitness of pollination generalist and specialist plants were similarly negatively affected by land-use change, whereas male fitness of specialist plants showed no effects.
CONCLUSIONS
Our findings indicate that angiosperm populations remaining in fragmented habitats negatively affect pollination, and female and male fitness, which will likely decrease the recruitment, survival, and long-term viability of plant populations remaining in fragmented landscapes. We underline the main current gaps of knowledge for future research agendas and call out not only for a decrease in the current rates of land-use changes across the world but also to embark on active restoration efforts to increase the area and connectivity of remaining natural habitats.
PubMed: 38722218
DOI: 10.1093/aob/mcae076 -
Trends in Plant Science Jul 2023In addition to positive effects on plant growth and resilience, sound alerts plants of potential danger and aids in defense. Sound guides plants towards essential... (Review)
Review
In addition to positive effects on plant growth and resilience, sound alerts plants of potential danger and aids in defense. Sound guides plants towards essential resources, like water, through phonotropic root growth. Sound also facilitates mutualistic interactions such as buzz pollination. Molecularly, sound induces Ca signatures, K fluxes, and an increase in reactive oxygen species (ROS) levels in a mechanosensitive ion channel-dependent fashion. We review the two major open questions in the field of plant acoustics: (i) what is the ecological relevance of sound in plant life, and (ii) how is sound sensed and transduced to evoke a morphophysiological response? We highlight the clear need to combine the ecological and molecular perspectives for a more holistic approach to better understand plant behavior.
Topics: Sound; Pollination; Reactive Oxygen Species; Water; Plants; Perception
PubMed: 37002001
DOI: 10.1016/j.tplants.2023.03.003 -
PloS One 2023Fungicides are used in agriculture to protect crops from various fungal diseases. However, they may modulate the plants metabolism. Moreover, fungicides can accumulate...
Fungicides are used in agriculture to protect crops from various fungal diseases. However, they may modulate the plants metabolism. Moreover, fungicides can accumulate in the environment and may cause toxic effects on non-target organisms such as nectar microbes and pollinators. Nectar microbes contribute to the volatile profile of flowers and can influence pollinators behaviour. Thus, fungicide treatment could potentially affect the pollination. In this study, we investigated the influence of fungicide treatment on floral attributes as well as the behavioural impact on bumblebees. In separate experiments, we used one or both strawberry cultivars (Fragaria × ananassa var. Darselect and Malwina), which were either kept untreated (control) or treated with either Cuprozin® progress or SWITCH® fungicide. We analysed various flower traits including volatiles, pollen weight, pollen protein, and the attraction of bumblebees towards the flowers in the greenhouse. Additionally, we analysed the viability of pollen and pollen live-to-dead ratio, as well as the composition of nectar fungi in the field. A treatment with Cuprozin® progress led to a lower emission of floral volatiles and a slightly lower pollen protein content. This had no impact on the visit latency of bumblebees but on the overall visit frequency of these flowers. The treatment with the fungicide SWITCH® resulted in a higher emission of floral volatiles as well as a delayed first visit by bumblebees. Furthermore, flowers of control plants were visited more often than those treated with the two fungicides. Plant-pollinator interactions are highly complex, with many contributing factors. Fungicides can have an impact on the pollen quality and pollinator attraction, potentially leading to an altered pollen dispersal by pollinators and a change in fruit quality.
Topics: Bees; Animals; Pollination; Plant Nectar; Fragaria; Fungicides, Industrial; Odorants; Flowers; Pollen
PubMed: 37498837
DOI: 10.1371/journal.pone.0289283 -
Proceedings of the National Academy of... Sep 2023Many plant species in historically fire-dependent ecosystems exhibit fire-stimulated flowering. While greater reproductive effort after fire is expected to result in...
Many plant species in historically fire-dependent ecosystems exhibit fire-stimulated flowering. While greater reproductive effort after fire is expected to result in increased reproductive outcomes, seed production often depends on pollination, the spatial distribution of prospective mates, and the timing of their reproductive activity. Fire-stimulated flowering may thus have limited fitness benefits in small, isolated populations where mating opportunities are restricted and pollination rates are low. We conducted a 6-y study of 6,357 (Asteraceae) individuals across 35 remnant prairies in Minnesota (USA) to experimentally evaluate how fire effects on multiple components of reproduction vary with population size in a common species. Fire increased annual reproductive effort across populations, doubling the proportion of plants in flower and increasing the number of flower heads 65% per plant. In contrast, fire's influence on reproductive outcomes differed between large and small populations, reflecting the density-dependent effects of fire on spatiotemporal mating potential and pollination. In populations with fewer than 20 individuals, fire did not consistently increase pollination or annual seed production. Above this threshold, fire increased mating potential, leading to a 24% increase in seed set and a 71% increase in annual seed production. Our findings suggest that density-dependent effects of fire on pollination largely determine plant reproductive outcomes and could influence population dynamics across fire-dependent systems. Failure to account for the density-dependent effects of fire on seed production may lead us to overestimate the beneficial effects of fire on plant demography and the capacity of fire to maintain plant diversity, especially in fragmented habitats.
Topics: Humans; Ecosystem; Genetic Fitness; Reproduction; Pollination; Seeds
PubMed: 37722060
DOI: 10.1073/pnas.2306967120 -
Studies in Health Technology and... Nov 2023Colony Collapse disorder (the CCD) is the term used to describe the global decline in bee populations. The research mission of this article is to identify which factors...
Colony Collapse disorder (the CCD) is the term used to describe the global decline in bee populations. The research mission of this article is to identify which factors contribute to the CCD and understand how these factors contribute to the decline of bee populations, which may provide methods for restoring global bee populations. Two parts of the study will be mentioned in this article. The first half of our study was to understand such collective intelligence (and habits such as seasonal behavioral change) and use a mathematical model to simulate it. We then input the variables that we used to simulate honeybee collective intelligence into a time-dependent model to predict the population of a honey colony over time. In this model, we excluded the factors that might cause the CCD on purpose, so we could use it as a controlled set of honeybee natural population dynamics. We compared the results of this population model to experimental data we found, and they matched within certain degrees. The second half of our study was to perform a sensitivity analysis by introducing back the three factors that might cause the CCD to the population model including climate change, pesticides, and habitat destruction. The paper further discussed the strength and weaknesses of the mathematical model and used this model to predict how many honeybee hives were needed to support the pollination of a 20-acre parcel of land containing crops that benefit from pollination. Additionally, an infographic of our method was illustrated.
Topics: Bees; Animals; Models, Theoretical; Pollination; Colony Collapse; Population Dynamics
PubMed: 38007728
DOI: 10.3233/SHTI230827 -
Ecology and Evolution Nov 2023Honey bees are efficient pollinators of flowering plants, aiding in the plant reproductive cycle and acting as vehicles for evolutionary processes. Their role as agents...
Honey bees are efficient pollinators of flowering plants, aiding in the plant reproductive cycle and acting as vehicles for evolutionary processes. Their role as agents of selection and drivers of gene flow is instrumental to the structure of plant populations, but historically, our understanding of their influence has been limited to predominantly insect-dispersed flowering species. Recent metagenetic work has provided evidence that honey bees also forage on pollen from anemophilous species, suggesting that their role as vectors for transmission of plant genetic material is not confined to groups designated as entomophilous, and leading us to ask: could honey bees act as dispersal agents for non-flowering plant taxa? Using an extensive pollen metabarcoding dataset from Canada, we discovered that honey bees may serve as dispersal agents for an array of sporophytes (, , , , , ) and bryophytes (, , , ). Our findings also suggest that honey bees may occasionally act as vectors for the dispersal of aquatic phototrophs, specifically and , species of green algae. Our work has shed light on the broad resource-access patterns that guide plant-pollinator interactions and suggests that bees could act as vectors of gene flow, and potentially even agents of selection, across Plantae.
PubMed: 37941738
DOI: 10.1002/ece3.10645