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American Journal of Botany Jun 2023The movement of pollen grains from anthers to stigmas, often by insect pollinator vectors, is essential for plant reproduction. However, pollen is also a unique vehicle... (Review)
Review
The movement of pollen grains from anthers to stigmas, often by insect pollinator vectors, is essential for plant reproduction. However, pollen is also a unique vehicle for viral spread. Pollen-associated plant viruses reside on the outside or inside of pollen grains, infect susceptible individuals through vertical or horizontal infection pathways, and can decrease plant fitness. These viruses are transferred with pollen between plants by pollinator vectors as they forage for floral resources; thus, pollen-associated viral spread is mediated by floral and pollen grain phenotypes and pollinator traits, much like pollination. Most of what is currently known about pollen-associated viruses was discovered through infection and transmission experiments in controlled settings, usually involving one virus and one plant species of agricultural or horticultural interest. In this review, we first provide an updated, comprehensive list of the recognized pollen-associated viruses. Then, we summarize virus, plant, pollinator vector, and landscape traits that can affect pollen-associated virus transmission, infection, and distribution. Next, we highlight the consequences of plant-pollinator-virus interactions that emerge in complex communities of co-flowering plants and pollinator vectors, such as pollen-associated virus spread between plant species and viral jumps from plant to pollinator hosts. We conclude by emphasizing the need for collaborative research that bridges pollen biology, virology, and pollination biology.
Topics: Satellite Viruses; Virome; Plants; Pollen; Pollination; Flowers
PubMed: 36924316
DOI: 10.1002/ajb2.16144 -
Scientific Reports Feb 2023Three pollination methods are commonly used in the greenhouse cultivation of tomato. These are pollination using insects, artificial pollination (by manually vibrating...
Three pollination methods are commonly used in the greenhouse cultivation of tomato. These are pollination using insects, artificial pollination (by manually vibrating flowers), and plant growth regulators. Insect pollination is the preferred natural technique. We propose a new pollination method, using flower classification technology with Artificial Intelligence (AI) administered by drones or robots. To pollinate tomato flowers, drones or robots must recognize and classify flowers that are ready to be pollinated. Therefore, we created an AI image classification system using a machine learning convolutional neural network (CNN). A challenge is to successfully classify flowers while the drone or robot is constantly moving. For example, when the plant is shaking due to wind or vibration caused by the drones or robots. The AI classifier was based on an image analysis algorithm for pollination flower shape. The experiment was performed in a tomato greenhouse and aimed for an accuracy rate of at least 70% for sufficient pollination. The most suitable flower shape was confirmed by the fruiting rate. Tomato fruit with the best shape were formed by this method. Although we targeted tomatoes, the AI image classification technology is adaptable for cultivating other species for a smart agricultural future.
Topics: Animals; Solanum lycopersicum; Robotics; Artificial Intelligence; Robotic Surgical Procedures; Insecta; Technology; Flowers; Pollination
PubMed: 36750598
DOI: 10.1038/s41598-023-27971-z -
Oecologia Oct 2022Even though a high fraction of angiosperm plants depends on animal pollinators for sexual reproduction, little is known how pollinator service changes across the ranges...
Even though a high fraction of angiosperm plants depends on animal pollinators for sexual reproduction, little is known how pollinator service changes across the ranges of plant species and whether it may contribute to range limits. Here, we tested for variation in pollinator service in the North American Arabidopsis lyrata from its southern to northern range edge and evaluated the driving mechanisms. We monitored insect pollinators using time-lapse cameras in 13 populations over two years and spotted 67 pollinating insect taxa, indicating the generalist nature of this plant-pollinator system. Pollinator service was highest at intermediate local flower densities and higher in large compared to small plant populations. Southern populations had generally smaller population sizes, and visitation rate and pollination ratio decreased with latitude. We also found that pollinator visitation was positively correlated with the richness of other flowering plants. This study indicates that plant populations at southern range edges receive only marginal pollinator service if they are small, and the effect of lower pollination is also detectable within populations across the range when the local flower density is low. Results, therefore, suggest the potential for an Allee effect in pollination that manifests itself across spatial scales.
Topics: Animals; Arabidopsis; Flowers; Insecta; Plants; Pollination; Reproduction
PubMed: 36053350
DOI: 10.1007/s00442-022-05237-1 -
Specialized cockroach pollination in the rare and endangered plant Vincetoxicum hainanense in China.American Journal of Botany Oct 2020Species of Apocynaceae are pollinated by a diverse assemblage of animals. Here we report the first record of specialized cockroach pollination in the family, involving...
PREMISE
Species of Apocynaceae are pollinated by a diverse assemblage of animals. Here we report the first record of specialized cockroach pollination in the family, involving an endangered climbing vine species, Vincetoxicum hainanense in China. Experiments were designed to provide direct proof of cockroach pollination and compare the effectiveness of other flower visitors.
METHODS
We investigated the reproductive biology, pollination ecology, pollinaria removal, pollinia insertion, and fruit set following single visits by the most common insects. In addition, we reviewed reports of cockroaches as pollinators of other plants and analyzed the known pollination systems in Vincetoxicum in a phylogenetic context.
RESULTS
The small, pale green flowers of V. hainanense opened during the night. The flowers were not autogamous, but were self-compatible. Flower visitors included beetles, flies, ants and bush crickets, but the most effective pollinator was the cockroach Blattella bisignata, the only visitor that carried pollen between plants. Less frequent and effective pollinators are ants and Carabidae. Plants in this genus are predominantly pollinated by flies, moths and wasps.
CONCLUSIONS
Globally, only 11 plant species are known to be cockroach-pollinated. Because their range of floral features encompass similarities and differences, defining a "cockroach pollination syndrome" is difficult. One commonality is that flowers are often visited by insects other than cockroaches, such as beetles, that vary in their significance as pollinators. Cockroach pollination is undoubtedly more widespread than previously thought and requires further attention.
Topics: Animals; China; Cockroaches; Flowers; Phylogeny; Pollination; Vincetoxicum
PubMed: 33098337
DOI: 10.1002/ajb2.1545 -
Nature Communications Mar 2021Artificial light at night has rapidly spread around the globe over the last decades. Evidence is increasing that it has adverse effects on the behavior, physiology, and...
Artificial light at night has rapidly spread around the globe over the last decades. Evidence is increasing that it has adverse effects on the behavior, physiology, and survival of animals and plants with consequences for species interactions and ecosystem functioning. For example, artificial light at night disrupts plant-pollinator interactions at night and this can have consequences for the plant reproductive output. By experimentally illuminating natural plant-pollinator communities during the night using commercial street-lamps we tested whether light at night can also change interactions of a plant-pollinator community during daytime. Here we show that artificial light at night can alter diurnal plant-pollinator interactions, but the direction of the change depends on the plant species. We conclude that the effect of artificial light at night on plant-pollinator interactions is not limited to the night, but can also propagate to the daytime with so far unknown consequences for the pollinator community and the diurnal pollination function and services they provide.
Topics: Animals; Circadian Rhythm; Insecta; Plants; Pollination
PubMed: 33727549
DOI: 10.1038/s41467-021-22011-8 -
American Journal of Botany Apr 2022Pollinator declines can reduce the quantity and quality of pollination services, resulting in less pollen deposited on flowers and lower seed production by plants. In...
PREMISE
Pollinator declines can reduce the quantity and quality of pollination services, resulting in less pollen deposited on flowers and lower seed production by plants. In response to these reductions, plant species that cannot autonomously self-pollinate and thus are dependent on pollinators to set seed could plastically adjust their floral traits. Such plasticity could increase the opportunity for outcross pollination directly, as well as indirectly by affecting inflorescence traits.
METHODS
To test whether plants can respond to pollinator declines by plastically adjusting their floral traits, we simulated declines by experimentally reducing pollinator access to Lobelia siphilitica plants and measuring two traits of early- and late-season flowers: (1) floral longevity; and (2) sex-phase duration. To test whether plasticity in these floral traits affected inflorescence traits, we measured daily display size and phenotypic gender.
RESULTS
We found that experimentally reducing pollination did not affect female-phase duration, but did extend the male-phase duration of early-season flowers by 13% and the longevity of late-season flowers by 12.8%. However, plants with an extended male phase did not have a more male-biased phenotypic gender, and plants with an extended floral longevity did not have a larger daily display.
CONCLUSIONS
Our results suggest that plants can respond to pollinator declines by plastically adjusting both the longevity and sex-phase duration of their flowers. If this plasticity increases the opportunity for outcross pollination, then it could be one mechanism by which pollinator-dependent plant species maintain seed production as pollinators decline.
Topics: Flowers; Inflorescence; Lobelia; Plants; Pollen; Pollination
PubMed: 35253215
DOI: 10.1002/ajb2.1837 -
Journal of Evolutionary Biology Jan 2022Species interactions shape the evolution of traits, life histories and the pattern of speciation. What is less clear is whether certain types of species interaction are...
Species interactions shape the evolution of traits, life histories and the pattern of speciation. What is less clear is whether certain types of species interaction are more or less likely to lead to phenotypic divergence among species. We used the brood pollination mutualism between yuccas and yucca moths to test how mutualistic (pollination) and antagonistic (oviposition) traits differ in the propensity to increase phenotypic divergence among pollinator moths. We measured traits of the tentacular mouthparts, structures used by females to actively pollinate flowers, as well as ovipositor traits to examine differences in the rate of evolution of these two suites of traits among pollinator species. Morphological analyses revealed two distinct groups of moths based on ovipositor morphology, but no such groupings were identified for tentacle morphology, even for moths that pollinated distantly related yuccas. In addition, ovipositor traits evolved at significantly faster rates than tentacular traits. These results support theoretical work suggesting that antagonism is more likely than mutualism to lead to phenotypic divergence.
Topics: Animals; Flowers; Moths; Oviposition; Pollination; Symbiosis; Yucca
PubMed: 34855267
DOI: 10.1111/jeb.13967 -
Proceedings. Biological Sciences Oct 2023Mating success of flowering plants depends strongly on the efficiencies of pollen removal from flowers and its subsequent dispersal to conspecific stigmas. We...
Mating success of flowering plants depends strongly on the efficiencies of pollen removal from flowers and its subsequent dispersal to conspecific stigmas. We characterized the economy of pollen dispersal in flowering plants by analysing pollen fates and their correlates for 228 species. The mean percentage of pollen removed from flowers (removal efficiency) varied almost twofold according to the type of pollen-dispersal unit, from less than 45% for orchids and milkweeds with solid pollinia, to greater than 80% for species with granular monads or sectile (segmented) pollinia. The mean percentage of removed pollen reaching stigmas (pollen transfer efficiency, PTE) varied from 2.4% for species with separate monads to 27.0% for orchids with solid pollinia. These values tended to be higher in plants with single pollinator species and in those with non-grooming pollinators. Nectar production increased removal efficiency, but did not influence PTE. Among types of pollen-dispersal units, the net percentage of produced pollen that was dispersed to stigmas varied negatively with removal efficiency and positively with PTE, indicating the relative importance of the latter for overall pollen economy. These findings confirm the key importance of floral traits, particularly pollen packaging, for pollen dispersal outcomes and highlight the under-appreciated pollination efficiency of non-grooming pollinators.
Topics: Magnoliopsida; Pollen; Reproduction; Pollination; Plants; Flowers
PubMed: 37788703
DOI: 10.1098/rspb.2023.1148 -
Philosophical Transactions of the Royal... Jun 2022Bee and non-bee insect pollinators play an integral role in the quantity and quality of production for many food crops, yet there is growing evidence that nutritional... (Review)
Review
Bee and non-bee insect pollinators play an integral role in the quantity and quality of production for many food crops, yet there is growing evidence that nutritional challenges to pollinators in agricultural landscapes are an important factor in the reduction of pollinator populations worldwide. Schemes to enhance crop pollinator health have historically focused on floral resource plantings aimed at increasing pollinator abundance and diversity by providing more foraging opportunities for bees. These efforts have demonstrated that improvements in bee diversity and abundance are achievable; however, goals of increasing crop pollination outcomes via these interventions are not consistently met. To support pollinator health and crop pollination outcomes in tandem, habitat enhancements must be tailored to meet the life-history needs of specific crop pollinators, including non-bees. This will require greater understanding of the nutritional demands of these taxa together with the supply of floral and non-floral food resources and how these interact in cropping environments. Understanding the mechanisms underlying crop pollination and pollinator health in unison across a range of taxa is clearly a win-win for industry and conservation, yet achievement of these goals will require new knowledge and novel, targeted methods. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.
Topics: Agriculture; Animals; Bees; Crop Production; Crops, Agricultural; Ecosystem; Pollination
PubMed: 35491607
DOI: 10.1098/rstb.2021.0170 -
Journal of Economic Entomology Apr 2021Buzz-pollinated plants require visitation from vibration producing bee species to elicit full pollen release. Several important food crops are buzz-pollinated including... (Meta-Analysis)
Meta-Analysis
Buzz-pollinated plants require visitation from vibration producing bee species to elicit full pollen release. Several important food crops are buzz-pollinated including tomato, eggplant, kiwi, and blueberry. Although more than half of all bee species can buzz pollinate, the most commonly deployed supplemental pollinator, Apis mellifera L. (Hymenoptera: Apidae; honey bees), cannot produce vibrations to remove pollen. Here, we provide a list of buzz-pollinated food crops and discuss the extent to which they rely on pollination by vibration-producing bees. We then use the most commonly cultivated of these crops, the tomato, Solanum lycopersicum L. (Solanales: Solanaceae), as a case study to investigate the effect of different pollination treatments on aspects of fruit quality. Following a systematic review of the literature, we statistically analyzed 71 experiments from 24 studies across different geopolitical regions and conducted a meta-analysis on a subset of 21 of these experiments. Our results show that both supplemental pollination by buzz-pollinating bees and open pollination by assemblages of bees, which include buzz pollinators, significantly increase tomato fruit weight compared to a no-pollination control. In contrast, auxin treatment, artificial mechanical vibrations, or supplemental pollination by non-buzz-pollinating bees (including Apis spp.), do not significantly increase fruit weight. Finally, we compare strategies for providing bee pollination in tomato cultivation around the globe and highlight how using buzz-pollinating bees might improve tomato yield, particularly in some geographic regions. We conclude that employing native, wild buzz pollinators can deliver important economic benefits with reduced environmental risks and increased advantages for both developed and emerging economies.
Topics: Animals; Bees; Blueberry Plants; Crops, Agricultural; Solanum lycopersicum; Pollen; Pollination
PubMed: 33615362
DOI: 10.1093/jee/toab009