The Energetics of Pollination

ArticleinAnnals of the Missouri Botanical Garden 6(2):139-170 · November 2003with11 Reads
Impact Factor: 1.05 · DOI: 10.1146/annurev.es.06.110175.001035
Abstract

Provides contrasting examples illustrating different concepts, and points out what these suggest in regard to new and productive research. -from Author

    • "...iferentes flores en diferentes plantas con el fin de satisfacer sus necesidades metabólicas (Heinrich, 1975). En resumen, la geitonogamia es una negativa pero inevitable consecuencia de mantener el entrecruz..."
      Además, las plantas pueden presentar heterogeneidad en su oferta de néctar, dado que hay mayor secreción cuando el estigma está completamente receptivo (sesgo femenino, Carlson & Harms, 2006 ) y las flores disminuyen su producción después de ser visitadas por los polinizadores (menor producción en flores sometidas a medidas repetidas). Los polinizadores, en particular las abejas, pueden discriminar entre flores con altas y bajas recompensas florales, lo cual beneficia la transferencia de polen porque las abejas tendrían que visitar diferentes flores en diferentes plantas con el fin de satisfacer sus necesidades metabólicas (Heinrich, 1975). En resumen, la geitonogamia es una negativa pero inevitable consecuencia de mantener el entrecruzamiento en el proceso de exportar e importar polen e incrementar el éxito reproductivo masculino y femenino (Harder & Barret, 1995; Mitchell et al., 2004).
    [Show abstract] [Hide abstract] ABSTRACT: Abstract: Vaccinium meridionale is a wild plant producing edible fruits in the mountain areas of Northern South America. However, the fruits of this species has been under an unsustainable extraction and there is a growing interest of establishing this species as a crop; nevertheless, the information about its breeding system is scarce, which is essential for its sustainable management and conservation. This research aimed to study the floral and reproductive biology of V. meridionale in natural conditions, and to analyze the importance of pollinators on its reproduction, in two wild populations of V. meridionale in the states of Cundinamarca and Boyacá, in the Oriental Cordillera of Colombia. For this, we have made different observations and experiments to describe its flower morphology, floral phenology, pollen viability, stigma receptivity, pollen-ovule ratio and nectar production. To study its reproductive system, we performed experiments of flower emasculation, pollinator exclusion and hand pollination (self-and cross-pollination). We found that although the flowers have poricidal anthers, the release of pollen could occur easily without vibration. V. meridionale shows a large floral display, long floral longevity and has female-biased nectar production. The pollen-ovule ratio was of 571±133, which classified the species as facultative xenogamy. This result agreed with the pollination experiments because the plants produced fruits by agamospermy, selfing and outcrossing. However, we registered a strong inbreeding depression, observed in high rates of fruit abortions, after self-pollination. Unlike of self-pollinating fruits, the plant retains those produced by cross-pollination since its formation. The floral traits showed by this species are mechanisms to favor a more diverse guild of floral visitors than only insects able to buzz-pollination. In addition, these floral traits may enhance the pollination probability, and reduce geitonogamy. Moreover, the inbreeding depression suggests that V. meridionale promotes outcrossing as its main reproductive strategy. Therefore, pollinators, particularly bees, are essential for this species reproduction and conservation, and are critical in the maintenance of its genetic variability and fruits production.
    Full-text · Article · Dec 2015 · Revista de biologia tropical
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    • "...on, also benefits insects because they do not have to learn how to handle different flowers (Heinrich, 1975). It therefore increases their collector efficiency (Eickwort and Ginsberg, 1980). ..."
      It is advantageous for plant species, if pollinators remain constant to a single species during long periods of time (Bosch, 1986). This fact, besides helping plant fertilization, also benefits insects because they do not have to learn how to handle different flowers (Heinrich, 1975). It therefore increases their collector efficiency (Eickwort and Ginsberg, 1980).
    [Show abstract] [Hide abstract] ABSTRACT: Helianthemum caput-felis is an endangered plant species growing in fragmented habitats in the western Mediterranean basin. Reproductive traits, breeding system and pollinator assemblage were studied in its largest known (mainland) European population to improve knowledge on the reproductive biology of the species. Hand-pollination experiments were carried out to determine the breeding system. Generalized linear mixed models (GLMM) were fitted to the data to evaluate the effect of treatment on fruit set and number of viable seeds per fruit. We also investigated the composition of the pollinator assemblage by direct observations, and studied their pollen load. Results were then compared to previous studies conducted in an island population. In the studied population, H. caput-felis is partially self-compatible, but mostly an outbreeder species, since outcrossed flowers produced many more fruits and seeds than self-pollinated ones. Conversely, pollination treatments did not affect reproductive output in the island population. We also found several differences between island and mainland composition of floral visitors, as it was expected. The study of pollen loads revealed that insects were mostly visiting H. caput-felis. Despite the low capacity to produce fruits with self-pollination, H. caput-felis presented no reproductive limitations in its main inland population. Reproductive characteristics along with differences among populations should be taken into account for adequate management and conservation practices.
    Full-text · Article · Oct 2015 · Flora - Morphology Distribution Functional Ecology of Plants
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    • "...iferentes flores en diferentes plantas con el fin de satisfacer sus necesidades metabólicas (Heinrich, 1975). En resumen, la geitonogamia es una negativa pero inevitable consecuencia de mantener el entrecruz..."
      Además, las plantas pueden presentar heterogeneidad en su oferta de néctar, dado que hay mayor secreción cuando el estigma está completamente receptivo (sesgo femenino, Carlson & Harms, 2006 ) y las flores disminuyen su producción después de ser visitadas por los polinizadores (menor producción en flores sometidas a medidas repetidas). Los polinizadores, en particular las abejas, pueden discriminar entre flores con altas y bajas recompensas florales, lo cual beneficia la transferencia de polen porque las abejas tendrían que visitar diferentes flores en diferentes plantas con el fin de satisfacer sus necesidades metabólicas (Heinrich, 1975). En resumen, la geitonogamia es una negativa pero inevitable consecuencia de mantener el entrecruzamiento en el proceso de exportar e importar polen e incrementar el éxito reproductivo masculino y femenino (Harder & Barret, 1995; Mitchell et al., 2004).
    [Show abstract] [Hide abstract] ABSTRACT: Vaccinium meridionale es una planta silvestre productora de frutos comestibles en las áreas montañosas del norte de Suramérica. Sin embargo, no hay información suficiente sobre su sistema reproductivo, lo cual es fundamental para su manejo y conservación dado que sus frutos son extraídos de forma no sostenible y hay un creciente interés en establecer la especie como cultivo. Los objetivos de este trabajo fueron estudiar la biología floral y reproductiva de V. meridionale en condiciones naturales y analizar la importancia de los polinizadores en su reproducción. Para esto se realizaron observaciones y experimentos para describir su morfología y fenología floral, viabilidad de polen, receptividad de estigma, relación polen óvulo y producción de néctar. Para estudiar su sistema reproductivo se realizaron experimentos de emasculación, exclusión de polinizadores y polinización manual (autopolinización y polinización cruzada). El estudio se realizó con dos poblaciones silvestres de V. meridionale ubicadas en los departamentos de Cundinamarca y Boyacá, en la Cordillera Oriental de Colombia. Se encontró que aunque las flores tienen anteras poricidas la liberación del polen se da fácilmente sin vibración. V. meridionale presenta un gran despliegue y larga longevidad floral y hay un sesgo en la producción de néctar hacia la función femenina. Se estimó una relación polen/óvulo de 571±133, lo que clasifica a la especie como xenógama facultativa. Este resultado coincidió con los experimentos de polinización ya que en las dos poblaciones estudiadas las plantas produjeron frutos por agamospermia, autogamia y xenogamia. No obstante, se observó una fuerte depresión por endogamia manifestada en altas tasas de aborto de frutos producidos por autogamia a diferencia de los frutos provenientes de polinización cruzada que fueron retenidos por la planta desde su formación. Los rasgos florales presentados por la especie se consideran mecanismos para favorecer un gremio más diverso de visitantes florales que sólo los insectos capaces de polinización por vibración. Además, estos rasgos florales pueden aumentar la probabilidad de polinización y disminuir la geitonogamia. Igualmente la depresión por endogamia sugiere que la especie busca mantener el entrecruzamiento como su principal estrategia reproductiva. Por lo tanto, los polinizadores, en particular las abejas son fundamentales para la reproducción de V. meridionale y en consecuencia su conservación es esencial para mantener la variabilidad genética y oferta de frutos de esta especie.
    Full-text · Article · Oct 2015 · Revista de biologia tropical
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    • "...orts is influenced by spatial memory processes and the cost of flight and interactions with flowers212223, and thus also by the effective visual guidance of the pollinator's movements. It is therefore ..."
      Foraging decisions are not limited to the final stage of a floral visit. As the insect moves between flowers, the success of its foraging efforts is influenced by spatial memory processes and the cost of flight and interactions with flowers212223, and thus also by the effective visual guidance of the pollinator's movements. It is therefore important to consider the spatial scales, over which flower signals engage with visual and learning mechanisms, to understand the selective pressures that insect behaviour exerts on colour and pattern features of floral displays.
    [Show abstract] [Hide abstract] ABSTRACT: Flower patterns are thought to influence foraging decisions of insect pollinators. However, the resolution of insect compound eyes is poor. Insects perceive flower patterns only from short distances when they initiate landing or search for reward on the flower. From further away flower displays jointly form larger-sized patterns within the visual scene that will guide an insect's flight behaviour. Chromatic and achromatic cues in such patterns may help insects to find, approach and learn rewarded locations in a flower patch, bringing them close enough to individual flowers. Flight trajectories and the spatial resolution of chromatic and achromatic vision in insects determine the effectiveness of floral displays, and both need to be considered in studies of plant–pollinator communication.
    Full-text · Article · Oct 2015
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    • "...impson & Neff, 1981). Because animal pollinators forage to maximize reward gain (Synge, 1947; Heinrich, 1975), the fitness of plants is expected to be affected by how a pollinator responds to the perceived pr..."
      Pollen and nectar are the most common rewards offered by plants, in addition to other rewards, such as oils and resins (Simpson & Neff, 1981). Because animal pollinators forage to maximize reward gain (Synge, 1947; Heinrich, 1975), the fitness of plants is expected to be affected by how a pollinator responds to the perceived presence of rewards. Nectar is usually concealed in flowers, but its presence can be detected by visiting animals in some instances by its odour (Raguso, 2004) or correlations with flower size and stage of anthesis (often signalled by colour, e.g.
    [Show abstract] [Hide abstract] ABSTRACT: Flowering plants typically use floral rewards to attract animal pollinators. Unlike nectar, pollen rewards are usually visible and may thus function as a signal that influences landing decisions by pollen-seeking insects. Here we artificially manipulate the presence of both pollen and staminal hairs (a putative false signal of pollen reward availability) in the hermaphroditic lily Bulbine abyssinica (Xanthorrhoeaceae) to investigate their effects on bee visitation and fecundity, and also test for trade-offs between pollen production and seed production. Honeybees, the primary floral visitors, are probably not able to distinguish between colours of petals, staminal hairs and pollen of B. abyssinica, according to analysis of reflectance spectra in a bee vision model. Flowers with both pollen and hairs removed had the lowest levels of bee visitation, seed set and seed abortions. Flowers containing hairs had an ∼50% increase in visitation rate and seed set compared with emasculated flowers, while intact controls had the highest seed abortion rate. Ovule discounting in intact flowers is probably due to ovarian self-incompatibility (or strong early inbreeding depression) as ovules penetrated by tubes from self-pollen uniformly failed to develop into seeds. These results show that staminal hairs can enhance plant fecundity by increasing attraction of pollen-seeking insects to flowers without increasing the risk of ovule discounting through pollinator-mediated self-pollination. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, ●●, ●●–●●.
    Full-text · Article · Mar 2015 · Botanical Journal of the Linnean Society
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    • "...th. The energy intake rate during feeding influences foraging efficiency (Wolf et al., 1972; Heinrich, 1975; Whitham, 1977; May, 1988) and reproductive fitness (Hainsworth et al., 1991 ). Rapid feeding should..."
      Therefore , increased flower handling times of long-proboscid insects could result from problems with flower manipulation , deceleration of nectar intake or a combination of both. The energy intake rate during feeding influences foraging efficiency (Wolf et al., 1972; Heinrich, 1975; Whitham, 1977; May, 1988) and reproductive fitness (Hainsworth et al., 1991 ). Rapid feeding should therefore be favoured by natural selection (Emlen, 1966; Schoener, 1971; Pyke et al., 1977).
    [Show abstract] [Hide abstract] ABSTRACT: Extremely long proboscides are rare among butterflies outside of the Hesperiidae, yet representatives of several genera of skipper butterflies possess proboscides longer than 50 mm. Although extremely elongated mouthparts can be regarded as advantageous adaptations to gain access to nectar in deep-tubed flowers, the scarcity of long-proboscid butterflies is a phenomenon that has not been adequately accounted for. So far, the scarceness was explained by functional costs arising from increased flower handling times caused by decelerated nectar intake rates. However, insects can compensate for the negative influence of a long proboscis through changes in the morphological configuration of the feeding apparatus. Here, we measured nectar intake rates in 34 species representing 21 Hesperiidae genera from a Costa Rican lowland rainforest area to explore the impact of proboscis length, cross-sectional area of the food canal and body size on intake rate. Long-proboscid skippers did not suffer from reduced intake rates due to their large body size and enlarged food canals. In addition, video analyses of the flower-visiting behavior revealed that suction times increased with proboscis length, suggesting that long-proboscid skippers drink a larger amount of nectar from deep-tubed flowers. Despite these advantages, we showed that functional costs of exaggerated mouthparts exist in terms of longer manipulation times per flower. Finally, we discuss the significance of scaling relationships on the foraging efficiency of butterflies and why some skipper taxa, in particular, have evolved extremely long proboscides. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Full-text · Article · Feb 2015 · Journal of Evolutionary Biology
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