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In the current scenario of a general decline of the honeybee worldwide, studies on the potential of alternative bee species in pollinating cultivated plants are important. Although melon, Cucumis melo, is a crop with great commercial importance, there is very little information on its pollinating fauna in Europe, and none from the southern Mediterranean area. In a locality in central Spain, using both pan‐traps and net collections, we found that melon flowers are visited by 31 species of bees spanning four families, though only four were both dominant and constant. These four species belonged to the family Halictidae (sweat bees) and mostly (three species) to the genus Lasioglossum. Five other species could be defined as accessory: honeybee, Apis mellifera, and four other halictids. Individuals of the dominant species were smaller, on average, than those from all the other species. Observations on the frequency of pollen and nectar foraging and on flower visit duration further suggested L. malachurum as the potential key pollinator. Females of this species started to forage on melon early in the flowering season and exhibited two activity peaks in summer, thus covering the whole season. Although in other sites across continents melon seems to be more heavily pollinated by honeybees, this seems to be not the case in the Mediterranean, where sweat bees seem to be the major pollinators of this crop.  相似文献   

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In the present study, nectar and pollen sources for honeybee (Apls cerana cerana Fabr.) were studied in Qlnglan mangrove area, Hainan Island, China, based on microscopic analysis of honey and pollen load (corblcular and gut contents) from honeybees collected In October and November 2004. Qualitative and quantitative melittopalynologlcal analysis of the natural honey sample showed that the honey is of unlfloral type with Mimosa pudlca L. (Mlmosaceae) as the predominant (89.14%) source of nectar and pollen for A. cerana cerana In October. Members of Araceae are an Important minor (3%-15%) pollen type, whereas those of Arecaceae are a minor (〈3%) pollen type. Pollen grains of Nypa fruticans Wurmb., Rhlzophora spp., Excoecarla agallocha L., Lumnitzera spp., Brugulera spp., Kandella candel Druce, and Ceriops tagal (Perr.) C. B. Rob. are among the notable mangrove texa growing In Qinglan mangrove area recorded as minor taxa In the honey. The absolute pollen count (I.e. the number of pollen grains/10 g honey sample) suggests that the honey belongs to Group V (〉1 000 000). Pollen analysis from the corblcular and gut contents of A. cerana cerana revealed the highest representation (95.60%) of members of Sonneratia spp. (Sonneratlaceae), followed by Bruguiera spp. (Rhizophoraceae), Euphorblaceae, Poaceae, Fabaceae, Arecaceae, Araceae, Anacardlaceae, and Rublaceae. Of these plants, those belonging to Sonneratla plants are the most Important nectar and pollen sources for A. cerana cerana and are frequently foraged and pollinated by these bees in November.  相似文献   

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The buzzing foraging behavior of female bees for pollen harvesting called the attention of early pollination biologists. Flower types that demand this buzzing behavior comprise about 20,000 species of different and phylogenetically unrelated plant taxa, suggesting that it had independently evolved many times among the flowering plants. Between the late 1970s and early 1980s, theoretical papers had modeled the energetics of buzz pollination, but, up to this moment, no hypothesis was experimentally tested concerning the theoretical basis of the energetics of buzz pollination. We present a cost‐effective and simple apparatus, including a digital and highly accurate frequency generator, and a device for the transference of buzz‐frequency energy to the receptive floral unity. The receptive floral unities may comprise the entire or partial androecium, or the tubular corolla, or, in some cases, the whole flower. This apparatus can be easily used in both laboratory and field conditions of research, as natural air currents are avoided, and the response of pollen liberation can be quantitatively measured by pollen grain counts that can be captured by adhesion in slide poured with an isosmotic lactate–glycerol media. The maximum displacement of the hardwire beam/claw system was 0.1170 ± 0.0006 mm @ 150 Hz; 0.021 ± 0.003 mm @ 250 Hz; 0.010 ± 0.001 mm @ 350 Hz; 0.0058 ± 0.0001 mm @ 450 Hz; and 0.0082 ± 0.0005 mm @ 550 Hz. Hypothesis contrasting frequency emission and pollen liberation measured as pollen grain counts may be tested in a species flower type by simple linear regression if pollen counts are normally distributed, or ordinal logistic regression, with non‐normal counts. The comparison among different flower‐type requirements can be tested through appropriate statistical methods for both normally and non‐normally distributed pollen grain counts.  相似文献   

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Les insectes butineurs de Cucumis sativus L. (Cucurbitaceae) ont été étudiés durant les floraisons de 2001 et de 2002 dans la région de Constantine (est algérien). Les observations ont montré que la majorité des visiteurs de la plante sont des hyménoptères apoïdes. Apis mellifera L., Ceratina cucurbitina Rossi, Megachile leachella Curtis et M. pilidens Alfken sont les espèces les plus fréquentes sur les fleurs. Les proportions de visites des abeilles sont plus élevées sur les fleurs staminées que sur les fleurs pistilées. En moyenne, les quatre espèces ont visité entre 6 et 8 fleurs par minute et leurs durées de visite sur les fleurs pistilées sont significativement plus lentes en comparaison avec les fleurs staminées.  相似文献   

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陈璇  胡福良 《昆虫知识》2009,46(3):490-494
蜜蜂Apisspp.是一种社会性昆虫。社会性昆虫在对它们群体自身数量和巢穴环境的调节方面表现出明显的稳态特点,Emerson将这种稳态调节称为社会性稳态。蜂群中花粉的储存量就具有稳态的特点。蜂群的花粉采集行为是由蜂群对花粉的需要决定的。关于蜜蜂花粉采集行为的调控机制,目前的研究主要集中于是哪些信息以及蜂群是如何识别这些信息从而调控其采粉行为,主要形成了直接识别和间接识别2种假说。对这2种假说进行综述。  相似文献   

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1. Competition alters animal foraging, including promoting the use of alternative resources. It may also impact how animals feed when they are able to handle the same food with more than one tactic. Competition likely impacts both consumers and their resources through its effects on food handling, but this topic has received little attention. 2. Bees often use two tactics for extracting nectar from flowers: they can visit at the flower opening, or rob nectar from holes at the base of flowers. Exploitative competition for nectar is thought to promote nectar robbing. If so, higher competition among floral visitors should reduce constancy to a single foraging tactic as foragers will seek food using all possible tactics. To test this prediction, field observations and two experiments involving bumble bees visiting three montane Colorado plant species (Mertensia ciliata, Linaria vulgaris, Corydalis caseana) were used under various levels of inter- and intra-specific competition for nectar. 3. In general, individual bumble bees remained constant to a single foraging tactic, independent of competition levels. However, bees that visited M. ciliata in field observations decreased their constancy and increased nectar robbing rates as visitation rates by co-visitors increased. 4. While tactic constancy was high overall regardless of competition intensity, this study highlights some intriguing instances in which competition and tactic constancy may be linked. Further studies investigating the cognitive underpinnings of tactic constancy should provide insight on the ways in which animals use alternative foraging tactics to exploit resources.  相似文献   

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The mutualism between plants and pollinators is built upon the trophic ecology of flowers and florivores. Yet the ecology of flowers-as-food is left implicit in most studies of plant–pollinator ecology, and it has been largely neglected in mainstream trophic ecology. This deficit is especially evident in an emerging issue of basic and applied significance: competition between pollinators for floral resources. In this synthesis, we start by exploring the notion of floral resource limitation upon which most studies concerning competition between pollinators are tacitly predicated. Both theoretical and empirical lines of evidence indicate that floral resource limitation must be understood as a complex ecological contingency; the question is not simply whether but when, where and in what regions of floral trait space resources are limiting. Based on this premise, we propose a framework for understanding floral resource availability in terms of temporal, spatial and functional structure. While this framework is conceptually intuitive, it is empirically and analytically demanding. We review existing methods for measuring and summarizing the multi-dimensional structure of floral resources, highlight their strengths and weaknesses, and identify opportunities for future methods development. We then discuss the causal relationships linking floral resource structure to species coexistence, plant–pollinator community dynamics, and exogenous drivers like climate, land use, and episodic disturbances. In its role as both cause and effect, floral resource structure mediates the relationship between behavioral ecology, landscape ecology, and coexistence theory with respect to flowers and florivores. Establishing floral resource structure as an object of study and application will both shed light on basic questions of coexistence and guide management decisions concerning contentious issues such as the compatibility of apiculture with wild pollinator conservation and the appropriate use of floral enhancements in agri-environment schemes.  相似文献   

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Floral variation among closely related species is thought to often reflect differences in pollination systems. Flowers of the large genus Impatiens are characterized by extensive variation in colour, shape and size and in anther and stigma positioning, but studies of their pollination ecology are scarce and most lack a comparative context. Consequently, the function of floral diversity in Impatiens remains enigmatic. This study documents floral variation and pollination of seven co‐occurring Impatiens spp. in the Southeast Asian diversity hotspot. To assess whether floral trait variation reflects specialization for different pollination systems, we tested whether species depend on pollinators for reproduction, identified animals that visit flowers, determined whether these visitors play a role in pollination and quantified and compared key floral traits, including floral dimensions and nectar characteristics. Experimental exclusion of insects decreased fruit and seed set significantly for all species except I. muscicola, which also received almost no visits from animals. Most species received visits from several animals, including bees, birds, butterflies and hawkmoths, only a subset of which were effective pollinators. Impatiens psittacina, I. kerriae, I. racemosa and I. daraneenae were pollinated by bees, primarily Bombus haemorrhoidalis. Impatiens chiangdaoensis and I. santisukii had bimodal pollination systems which combined bee and lepidopteran pollination. Floral traits differed significantly among species with different pollination systems. Autogamous flowers were small and spurless, and did not produce nectar; bee‐pollinated flowers had short spurs and large floral chambers with a wide entrance; and bimodally bee‐ and lepidopteran‐pollinated species had long spurs and a small floral chamber with a narrow entrance. Nectar‐producing species with different pollination systems did not differ in nectar volume and sugar concentration. Despite the high frequency of bee pollination in co‐occurring species, individuals with a morphology suggestive of hybrid origin were rare. Variation in floral architecture, including various forms of corolla asymmetry, facilitates distinct, species‐specific pollen‐placement on visiting bees. Our results show that floral morphological diversity among Impatiens spp. is associated with both differences in functional pollinator groups and divergent use of the same pollinator. Non‐homologous mechanisms of floral asymmetry are consistent with repeated independent evolution, suggesting that competitive interactions among species with the same pollination system have been an important driver of floral variation among Impatiens spp.  相似文献   

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Despite honeybees (Apis mellifera L.) occurring as a feral and commercially managed species in many parts of Australia, the effects of honeybees on native Australian ecosystems are poorly understood. We examined the impacts of honeybee apiaries on Tasmanian Leatherwood Eucryphia lucida Labill. (Eucryphiaceae) by comparing commercial apiary sites with control sites >2 km from the nearest apiary. Feral honeybees were common at control sites (73% of honeybees feral) but were scarce at apiary sites (2%), and hive honeybees appeared to be competitively displacing feral honeybees near apiaries. Visit rates by native insects appeared to be un‐affected by the increased numbers of hive honeybees near apiaries. Standing crops of nectar sugar were significantly depressed at apiary sites. Pollen was rapidly removed from flowers at apiary sites resulting in full separation of the male and female flower‐phases (flowers completely dichogamous). In contrast, at control sites, pollen tended to remain in flowers into the female phase (flowers partially dichogamous). There was no difference in the total number of pollen grains deposited on stigmas or in percentage seed set among apiary and control sites. However, fruit set was elevated at apiary sites, possibly owing to reduced autonomous (within‐flower) selfing. Our study indicated that honeybees significantly reduce floral resources (nectar and pollen) around apiaries, although any competitive effects on native insects may have been obscured by large variation in the abundance of native insects among experimental sites.  相似文献   

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A rising global population will need more food, increasing demand for insect pollination services. However, general insect declines conflict with this demand. One way to mitigate this conflict is to grow crop flowers that are easier for insects to find and more rewarding to those that visit them. This study quantifies variation in the pollinator-relevant traits of nectar and pollen production, flower size and flower shape in commercial strawberry, finding significant variation between varieties in all traits. Bumblebees could learn to distinguish between the extremes of variation in flower shape, but this learning is very slow, indicating that this variation is at the limit of that which can be detected by bumblebees. Bee preferences for nectar of differing sugar concentrations at field-realistic volumes were consistent with previous observations at larger volumes, suggesting that it is valid to translate lab findings to the field. This study builds on our knowledge of the range of pollinator reward present in a single cultivated species and of the impact of field-realistic levels of variation in floral traits on bumblebee preferences.  相似文献   

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The ecology and evolution of pollen odors   总被引:9,自引:0,他引:9  
The literature is reviewed and new evidence presented that pollen produces odors, which serve multiple functions in pollination and defense. Pollen odor, which originates from pollenkitt, comprises volatiles that belong to the same chemical classes found in flower scents, that are in species-specific mixtures, and that contrast with odors of other floral parts. Pollen can also take up volatiles from surrounding floral odors, but this adsorption is selective and varies among species. Pollen odors are more pronounced in insect- than bird- or wind-pollinated plants, suggesting that volatile emission evolved in part under selection to attract pollinators. Pollen-feeding insects can perceive pollen odor and use it to discriminate between different pollen types and host plants. Pollen odor influences bee foraging, including the location of pollen sources, discrimination of flowers with different amounts of pollen, and hostplant recognition by pollen-specialist species. In the few wind-pollinated plants studied, odors of male flowers or pollen are comparatively high in -methyl alcohols and ketones; these volatiles may serve in pollen defense, with some known to repel insects. Pollen odor often includes chemicals with documented defense activity, which is probably aimed mainly at nonpollinator pollen-feeding insects and pathogens; an involvement in pollen allelopathy is also possible. Pollen volatiles comprise chemically diverse compounds that may play multiple roles, and their emission in pollen odor undoubtedly evolved under the principle, and often conflicting, selective pressures to both protect the male gametophyte and increase its dispersal by animals.  相似文献   

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Over 22,000 species of biotically pollinated flowering plants, including some major agricultural crops, depend primarily on bees capable of floral sonication for pollination services. The ability to sonicate (“buzz”) flowers is widespread in bees but not ubiquitous. Despite the prevalence of this pollinator behavior and its importance to natural and agricultural systems, the evolutionary history of floral sonication in bees has not been previously studied. Here, we reconstruct the evolutionary history of floral sonication in bees by generating a time‐calibrated phylogeny and reconstructing ancestral states for this pollen extraction behavior. We also test the hypothesis that the ability to sonicate flowers and thereby efficiently access pollen from a diverse assemblage of plant species, led to increased diversification among sonicating bee taxa. We find that floral sonication evolved on average 45 times within bees, possibly first during the Early Cretaceous (100–145 million years ago) in the common ancestor of bees. We find that sonicating lineages are significantly more species rich than nonsonicating sister lineages when comparing sister clades, but a probabilistic structured rate permutation on phylogenies approach failed to support the hypothesis that floral sonication is a key driver of bee diversification. This study provides the evolutionary framework needed to further study how floral sonication by bees may have facilitated the spread and common evolution of angiosperm species with poricidal floral morphology.  相似文献   

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Steane  Dorothy A. 《DNA research》2005,12(3):215-220
The complete nucleotide sequence of the chloroplast genome ofthe hardwood species Eucalyptus globulus is presented and comparedwith chloroplast genomes of tree and non-tree angiosperms andtwo softwood tree species. The 160 286 bp genome is similarin gene order to that of Nicotiana, with an inverted repeat(IR) (26 393 bp) separated by a large single copy (LSC) regionof 89 012 bp and a small single copy region of 18 488 bp. Thereare 128 genes (112 individual gene species and 16 genes duplicatedin the inverted repeat) coding for 30 transfer RNAs, 4 ribosomalRNAs and 78 proteins. One pseudogene (-infA) and one pseudo-ycf(-ycf15) were identified. The chloroplast genome of E. globulusis essentially co-linear with that of another hardwood treespecies, Populus trichocarpa, except that the latter lacks rps16and rpl32, and the IR has expanded in Populus to include rps19(part of the LSC in E. globulus). Since the chloroplast genomeof E. globulus is not significantly different from other treeand non-tree angiosperm taxa, a comparison of hardwood and softwoodchloroplasts becomes, in essence, a comparison of angiospermand gymnosperm chloroplasts. When compared with E. globulus,Pinus chloroplasts have a very small IR, two extra tRNAs andfour additional photosynthetic genes, lack any functional ndhgenes and have a significantly different genome arrangement.There does not appear to be any correlation between plant habitand chloroplast genome composition and arrangement.  相似文献   

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Honey bees collect distinct nutrient sources in the form ofnectar (energy) and pollen (nitrogen). We investigated the effectof varying energy stores on nectar and pollen foraging. We foundno significant changes in nectar foraging in response to changesin honey storage levels within colonies. Individual foragersdid not vary activity rates or nectar load sizes in responseto changes in honey stores, and colonies did not increase nectarintake rates when honey stores within the hive were decreased.This result contrasts with pollen foraging behavior, which isextremely sensitive to colony state. Our data show that individualforaging decisions during nectar collection and colony regulationof nectar intake are distincdy different from pollen foraging.The behavior of honey bees illustrates that foraging strategy(and therefore foraging models) can incorporate multiple currencies,including both energy and protein intake.[Behav Ecol 7: 286–291(1996)]  相似文献   

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When a pollination vector is required, any mechanism that contributes to floral visitation will potentially benefit the reproductive fitness of a plant. We studied the effect of floral colour change in the desert perennial Alkanna orientalis on the foraging behaviour of the solitary bee Anthophora pauperata . Flowers changed colour over time from bright yellow (with moderate nectar reward) to pale yellow/white (with significantly lower nectar reward). Bee visitation was non-random with respect to colour phase availability within the flower population and was biased towards the more rewarding flowers. At plants where the availability of colour phases had been manipulated experimentally to produce 'bright' or 'pale' plants, bees visited significantly more flowers (and for longer periods) on the bright plants. The change of flower colour was not simply age-related; we observed variation in the temporal course of colour change and our data suggest that visitation, leading to deposition of cross-pollen, can accelerate the process. In subpopulations with limited pollinators, Alkanna can influence bees by using their colour-related foraging preferences to alter visitation patterns.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 427–435.  相似文献   

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Pollen and nectar are usually lumped together as floral rewards for pollinating bees, but they play totally different roles for flowers and bees (Table 1), as well as in the relationship between them. While flowers are specialized for certain pollinators via nectar, bees specialize on certain flowers via pollen. While flowers need pollen as a prerequisite for pollination, it is the essential larval food in bees. Thus, there is a strong competition between them for pollen. Foraging for pollen must be divided into three phases: uptake in the flower, reloading into and homeward transport within a carrying container. Bees have specializations for transport but hardly any for pollen uptake - and thus for pollination. Bees actively harvesting pollen usually do not pollinate. This only happens as a consequence of contamination of the bee by pollen. From these data a scenario is provided for the evolution of bees and bee flowers. Specialized bee flowers are often characterized by their ability to hide pollen from the bees and at the same time use them as optimal pollinators. If the relationship of bees and flowers is mutualistic at all it is best described as a balanced mutual exploitation.  相似文献   

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