Amount Of Nectar Research Articles

Floral Reward, Advertisement and Attractiveness to Honey Bees in Dioecious Salix caprea

In dioecious, zoophilous plants potential pollinators have to be attracted to both sexes and switch between individuals of both sexes for pollination to occur. It often has been suggested that males and females require different numbers of visits for maximum reproductive success because male fertility is more likely limited by access to mates, whereas female fertility is rather limited by resource availability. According to sexual selection theory, males therefore should invest more in pollinator attraction (advertisement, reward) than females. However, our knowledge on the sex specific investment in floral rewards and advertisement, and its effects on pollinator behaviour is limited. Here, we use an approach that includes chemical, spectrophotometric, and behavioural studies i) to elucidate differences in floral nectar reward and advertisement (visual, olfactory cues) in dioecious sallow, Salix caprea, ii) to determine the relative importance of visual and olfactory floral cues in attracting honey bee pollinators, and iii) to test for differential attractiveness of female and male inflorescence cues to honey bees. Nectar amount and sugar concentration are comparable, but sugar composition varies between the sexes. Olfactory sallow cues are more attractive to honey bees than visual cues; however, a combination of both cues elicits the strongest behavioural responses in bees. Male flowers are due to the yellow pollen more colourful and emit a higher amount of scent than females. Honey bees prefer the visual but not the olfactory display of males over those of females. In all, the data of our multifaceted study are consistent with the sexual selection theory and provide novel insights on how the model organism honey bee uses visual and olfactory floral cues for locating host plants.

Morphological and Nectar Traits in Echeveria Rosea Lindley (Crassulaceae) Linked to Hummingbird Pollination in Central Veracruz, Mexico

Abstract: Flowers have evolved suites of traits that are associated with the attraction, reward and utilization of particular pollinator types. Specialization on particular pollinator functional group results in a particular combination of floral traits with consequences on plant fitness through efficient pollen delivery and pollen receipt at the population and species level. The aim of this study was to describe the floral morphology, nectar production patterns, floral visitors and natural fruit set in a population of Echeveria rosea Lindley (Crassulaceae) in central Veracruz, Mexico. The floral traits of Echeveria rosea correspond to the typical hummingbird pollination syndrome. The diurnal pattern of accumulated nectar (volume and amount of sugar) produced by the species corresponds to values reported for other hummingbird-pollinated species. Based on observations of foraging behavior, the Garnet-throated Hummingbird (Lamprolaima rhami) seems to be a more effective pollinator than the White-eared Hummi...

How does a floral colour‐changing species differ from its non‐colour‐changing congener? – a comparison of trait combinations and their effects on pollination

Summary Plant species sometimes exhibit dynamic contrasting patterns in terms of reproductive traits. Floral colour change – the retention of old, non‐productive, rewardless, but fully turgid flowers in an altered colour – has been considered as a plant strategy for enhancing pollinator attraction while minimizing visits to non‐reproductive flowers. Considering the perceptive and cognitive abilities of animals, these advantages should apply in most systems. It seems paradoxical, and therefore, that floral colour change occurs in only a portion of angiosperms. This divergence may be explained if floral colour change adds as yet unknown costs or benefits under specific conditions. To explore such possibilities, we compared details of trait combinations and pollination consequences between a floral colour‐changing (Weigela coraeensis) and a non‐colour‐changing (Weigela hortensis) species in a shared environment. Flowers of W. coraeensis secreted nectar for initial 2–3 days and remained white, after which they persisted for a few more days with discoloured, red purple petals and reduced nectar levels. Flowers of W. hortensis also secreted nectar for initial 2–3 days. They persisted for a few more days with the same colour and reduced amounts of nectar, but did so only when pollinators were scarce. Because only W. hortensis suffered from pollination difficulty at our site, both species retained their flowers for 4–5 days. Bees strongly preferred to visit W. coraeensis, leading to a greater proportion of seed set than in W. hortensis. In addition to their higher nectar productivity, only W. coraeensis plants offered bees colour difference as a visual cue to choose rewarding flowers and improve both long‐term and short‐term rates of nectar intake. By learning where to return, bees apparently responded to the difference in resource exploitability. Results indicate that floral colour change yields an additional benefit of attracting bee‐like pollinators that return preferentially to more easily exploitable plants. Under conditions where benefits of enhancing both conspicuousness and exploitability cannot outweigh the costs of doing so, however, retention of rewardless flowers in the same colour and flexibility in floral longevity – as was adopted in W. hortensis – may become more advantageous in terms of saving metabolic and ecological costs.

Identification of Plant Species for Crop Pollinator Habitat Enhancement in the Northern Prairies

Wild pollinators have a positive impact on the productivity of insect-pollinated crops. Consequently, landowners are being encouraged to maintain and grow wildflower patches to provide habitat for important pollinators. Research on plant-pollinator interaction matrices indicates that a small number of “core” plants provide a disproportionately high amount of pollen and nectar to insects. This matrix data can be used to help design wildflower plantings that provide optimal resources for desirable pollinators. Existing interaction matrices from three tall grass prairie preserves in the northern prairies were used to identify core plant species that are visited by wild pollinators of a common insect-pollinated crop, namely canola (Brassica napus L.). The wildflower preferences of each insect taxon were determined using quantitative insect visitation and floral abundance data. Phenology data were used to calculate the degree of floral synchrony between the wildflowers and canola. Using this information I ranked the 41 wildflowers that share insect visitors with canola according to how useful they are for providing pollinators with forage before and after canola flowers. The top five species were smooth blue aster (Symphyotrichum laeve (L.) A. & D. Löve), stiff goldenrod (Solidago rigida L.), wild bergamot (Monarda fistulosa L.), purple prairie-clover (Dalea purpurea Vent.) and Lindley’s aster (Symphyotrichum ciliolatum (Lindl.) A. & D. Löve). By identifying the most important wild insects for crop pollination, and determining when there will be “pollen and nectar gaps”, appropriate plant species can be selected for companion plantings to increase pollinator populations and crop production.

Nectar production in species of the Genus galanthus L. (Amaryllidaceae) from Serbia

As a contribution to the study of the melliferous flora of Serbia, nectar production in two species of the genus Galanthus L. (G. nivalis L., and G. elwesii Hook.) was investigated. The intensity of nectar secretion was determined directly, using the microcapillary method. The study included determination of the total daily nectar amount per flower, and an analysis of nectar secretion dynamics during the day and during the flower ontogeny. The results show that the total daily amount of nectar per flower is low, and flowers of both species exude nectar only once during the day and during the flower ontogeny. However, despite the low nectar production, Galanthus species represent a first valuable source of nectar and pollen to pollinators in the early spring period, when only a small number of species are in the flowering phenophase.

A Comparison of Artificial Bee Colony algorithm and Genetic Algorithm to Minimize the Makespan for Job Shop Scheduling

Job shop scheduling is predominantly an Non deterministic polynomial (NP)- complete challenge which is successfully tackled by the ABC algorithm by elucidating its convergence. The Job Shop Scheduling Problem (JSSP) is one of the most popular scheduling models existing in practice which is among the hardest combinatorial optimization problems. The ABC (Artificial Bee Colony) technique is concerned, it is observed that the entire specific artificial bees move about in a search space and select food sources by suitably adapting their location, know-how and having a full awareness of their nest inhabitants. Moreover, several scout bees soar and select the food sources discretely without making use of any skills. In the event of the quantity of the nectar in the fresh source becoming larger than the nectar quantity of an available source, they remember the fresh location and conveniently disregard the earlier position. In this way, the ABC system integrates local search techniques, executed by employed and onlooker bees, with universal search approaches, administered by onlookers and scouts. In our ambitious approach we have employed these three bees to furnish optimization in makespan, machine work load and the whole run period in an optimized method. In this way, with the efficient employment of our effective technique we make an earnest effort to minimize the makespan and number of machines. This paper compares GA to minimize the make span of the job scheduling process with ABC and proved that ABC algorithm produces the better result.

Seasonal reliance on nectar by an insectivorous bat revealed by stable isotopes

Many animals have seasonally plastic diets to take advantage of seasonally abundant plant resources, such as fruit or nectar. Switches from insectivorous diets that are protein rich to fruits or nectar that are carbohydrate rich present physiological challenges, but are routinely done by insectivorous songbirds during migration. In contrast, insectivorous bat species are not known to switch diets to consume fruit or nectar. Here, we use carbon stable isotope ratios to establish the first known case of a temperate bat species consuming substantial quantities of nectar during spring. We show that pallid bats (Antrozous pallidus) switch from a diet indistinguishable from that of sympatric insectivorous bat species in winter (when no cactus nectar is present) to a diet intermediate between those of insectivorous bats and nectarivorous bats during the spring bloom of a bat-adapted cactus species. Combined with previous results that established that pallid bats are effective pollinators of the cardon cactus (Pachycereus pringlei), our results suggest that the interaction between pallid bats and cardon cacti represents the first-known plant-pollinator mutualism between a plant and a temperate bat. Diet plasticity in pallid bats raises questions about the degree of physiological adaptations of insectivorous bats for incorporation of carbohydrate-rich foods, such as nectar or fruit, into the diet.

Interactions between hawkmoths and flowering plants in East Africa: polyphagy and evolutionary specialization in an ecological context

Hawkmoths (Lepidoptera, Sphingidae) are considered important pollinators in tropical regions, but the frequency and degree of reciprocal specialization of interactions between hawkmoths and flowers remain poorly understood. Detailed observations at two sites in Kenya over a two-year period indicate that adult hawkmoths are routinely polyphagous and opportunistic, regardless of their proboscis length. About 700 individuals of 13 hawkmoth species were observed visiting a wide range of plant species at the study sites, including 25 taxa that appear to be specifically adapted for pollination by hawkmoths. We estimate that 277 plant species in Kenya (c. 4.61% of the total angiosperm flora) are adapted for pollination by hawkmoths. Floral tube lengths of these plants have a bimodal distribution, reflecting the existence of two hawkmoth guilds differing in tongue length. Hawkmoths exhibited strongly crepuscular foraging patterns with activity confined to a 20-min period at dusk and, in some cases, a similar period just before dawn. Corolla tube length appears to act as a mechanical filter as the longest-tubed plants were visited by the fewest hawkmoth species and these were exclusively from the long-tongued guild. Tube length showed a strong positive relationship with nectar volume, even after phylogenetic correction, which implies that plants with long corolla tubes are under selection to offer relatively large amounts of nectar to entice visits by polyphagous long-tongued hawkmoths. Our study shows that diffusely co-evolved pollination systems involving long-tongued hawkmoths are clearly asymmetrical, with plants exhibiting a high degree of floral specialization, while hawkmoths exhibit polyphagous behaviour. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 199–213.

Soil and vegetation features determine the nested pattern of ant–plant networks in a tropical rainforest

Recently, several studies have focused on structural properties of ant–plant networks. However, little is known about the role of abiotic factors on these networks. As a result of different abiotic factors that can affect the patterns of ant–plant interactions, it was tested whether soil pH and canopy cover contribute to variation in the nestedness of mutualistic (plants with extrafloral nectar–EFN) and neutral (plants without EFN) ant–plant networks. It was shown that only mutualistic networks were affected by soil pH. It was suggested that this may occur because the variation in soil pH directly influences the secreted nectar, and as there is a preference for nectar composition by ants, this could change the patterns of interaction in mutualistic networks. As prey availability is possibly the main factor influencing ants' presence on plants without EFN, soil pH should have little or no influence on the patterns of interaction in neutral networks. On the other hand, nestedness was not affected by canopy cover in mutualistic and neutral networks. In spite of that canopy cover (light availability) is directly related to the amount of nectar secreted, the volume of nectar may not be important for the structure of the networks. However, canopy cover varied little in this study site. This small variation could not be enough to change the nested pattern in mutualistic and neutral networks. In short, the present results show that the abiotic factors that affect the availability and quality of food resources may have important effects on the structure of trophic interactions in non‐symbiotic ant–plant networks.

A modified artificial bee colony algorithm based on converge-onlookers approach for global optimization

Artificial bee colony (ABC) is a novel biological-inspired optimization algorithm, having the advantage of less control parameters, strong global optimization ability and easy to implement. It has received significant interest from researchers studying in different fields since it was invented. However, there are still some problems in ABC algorithm, such as slow to converge, easily get trapped in local optima and hard to find the best solution from all feasible solutions, and so on. In this work, we propose a modified algorithm called converge-onlookers ABC (COABC) algorithm. In order to improve the exploitation, a new solution search equation in the onlooker stage by applying the best solution of the previous iteration to guide the search of new candidate solutions was presented. In COABC algorithm, the roulette wheel selection mechanism based on nectar amounts of each food source was saved. Moreover, all employed bees to update not only once in each iteration, which helps improving both solution quality and convergence rate of ABC algorithm remarkably. The experimental results tested on numerical benchmark functions show that the COABC algorithm has excellent solution quality and convergence characteristics comparing to basic ABC algorithm and performs better than the state-of-art algorithm in some problems. The optimization result in solving the practical problem demonstrates the COABC is a prospect method and can be used in the engineering field.

Distribution, habitat disturbance and pollination of the endangered orchidBroughtonia cubensis(Epidendrae: Laeliinae)

The geographical distribution, population structure and pollination ecology are key aspects in the conservation and management of rare orchids. Here, we address these aspects and the main threats affecting the endangered Cuban orchid Broughtonia cubensis. This rewardless orchid is self-compatible, but pollinator dependent. However, seed production can be negatively affected by insect-mediated selfing. Three species of small bee (genera Ceratina and Lasioglossum) act as pollinators. As in the case of other nectarless orchids, we detected two species of plant producing large amounts of nectar in the area, the floral morphology of which closely resembles that of B. cubensis. The simultaneous flowering of these species could positively affect the reproductive success of B. cubensis. Nonetheless, the fitness of this orchid in natural conditions is low, possibly related to strong pollen limitation. To the problems arising from reduced fitness is added the fact that its historical distribution range has been greatly reduced in recent years. Throughout this study, we have detected dramatic reductions in the population sizes, in some cases as a result of human plundering, but also as a consequence of hurricanes. Based on the results of this study, we propose some guidelines to manage and conserve this orchid.

Nectar ecology of Datura ferox (Solanaceae): an invasive weed with nocturnal flowers in agro-ecosystems from central Argentina

Plant–pollinator interactions provide highly important ecological functions, and are influenced by floral nectar characteristics. The night blooming Datura ferox is an excellent model to test general hypotheses on the relationship between nectar traits (e.g., nectar secretion patterns, nectar chemical composition), pollinators and reproductive success for invasive, weedy species in highly modified ecosystems as crop fields. We hypothesized an adjustment between nectar composition and secretion dynamics through flower anthesis and the activity and requirements of nocturnal pollinators. Nectar chemical analyses showed low quantities of amino acids and lipids, phenolics, and alkaloids were not detected. D. ferox showed sucrose-dominant nectar with comparable amount of hexoses. Sugar proportions did not vary between populations or during flowering season. Most nectar is secreted before flower opening. Nectar resorption was detected at the end of anthesis. Experimentally drained flowers of both populations increased nectar production up to 50 % in the total amount of sugar per flower compared to control flowers. Nectar standing crop was relatively constant during the flowering season, but differences were detected between populations. Nectar traits of D. ferox would be favoring cross-pollination and maintaining seed production of this weed, since recently open flowers display a higher amount of nectar and they can renew nectar after a pollinator visit or reabsorb it at the end of anthesis. This nectar source may be important for native pollinators considering that human-induced forest fragmentation is related with the impoverishment of native flora from agro-ecosystems.

Testing non-additive effects of nectar-robbing ants and hummingbird pollination on the reproductive success of a parasitic plant

Nectar robbing may have an indirect negative effect on plant reproduction by discouraging legitimate pollinator species from visiting robbed flowers. In this study, we set up a 2 9 2 factorial design with nectar-robbing ants and hummingbird pollination to test for non-additive effects on fruit set, seed mass, and seed germination of the leafless mistletoe Tristerix aphyllus (Loranthaceae). Even though ants caused conspicuous damage at the base of the floral tubes, nectar availability was reduced by only 8 % in the presence of ants. The green-backed firecrown Sephanoides sephaniodes was insensitive to the presence of ants. Rather, the bird responded to flower number and the presence or the absence of damage, but not to the extent of damage within inflorescences. As hummingbirds were largely insen- sitive to variation in nectar robbing, the interaction ant 9 hummingbird had no effect on plant-reproduc- tive success. Thus, the factorial experiment did not provide evidence for indirect negative effects of nectar robbing on plant reproduction. These results suggest that indirect effects of nectar robbers on pollinator behaviour may occur under a more restricted set of conditions than those previously considered. We suggest that the low amount of nectar removed by nectar-robbing ants was insufficient for hummingbirds to avoid robbed flowers, which restricted the potential for non-additive effects.

Pollinators in biofuel agricultural systems: the diversity and performance of bees (Hymenoptera: Apoidea) on Jatropha curcas in Mexico

As with other biofuel crops, information on the effect of insect pollinators and landscape context on the productivity and sustainability of Jatropha curcas is lacking. We studied the effect of pollinator exclusion, self-pollination, cross-pollination and individual visits of the stingless bee Frieseomelitta nigra and the honey bee Apis mellifera on fruit set and weight of fruit and seed of J. curcas. We compared the relative abundance of both bee species on flowers and whether their attributes (ratio of male to female flowers, nectar quantity and quality) affect bee visitation rates. Finally, we sampled various plantations to analyze whether the proportion of forest surrounding a site affects bee abundance and diversity. Significant higher rates of fruit set were obtained from open, cross-pollinated, F. nigra and A. mellifera visited flowers compared to self-pollinated and non-pollinated ones revealing the importance of bees for fruit production. Frieseomelitta nigra and A. mellifera had a similar effect on fruit set and quality, but the former was significantly more abundant on the crop suggesting a better pollinator performance. Male flowers were significantly more visited than female ones by both bee species in spite of their similar amounts of nectar and sugar. The proportion of forest in the surrounding matrix had a positive correlation with bee diversity and abundance on plantations. Our results indicate that preserving patches of forest around the plantations may increase the presence of native bees on Jatropha flowers and ensure sustainable levels of pollination.

Structure of floral nectaries, nectar production and sugar composition in nectar of 7 species of Vicia L. Fabaceae

Nectaries of investigated species of <em>Vicia</em> were ranked into 3 morphological types: automorphic (<em>V. sepium</em> L.), transitoric (<em>V. angustifolia</em> L., <em>V. sativa</em> L., <em>V. villosa</em> Roth, <em>V. cracca</em> L.) and flat, epimorphic (<em>V. hirsuta</em> (L.) S. F. Gray and <em>V. tetrasperma</em> (L.) Schreb.). The best nectaring was connected with well defined nectary structure, and moreover quantity of nectar was correlated with nectary size but was not depended on number of secretory stomata. Sucrose dominated in the nectar of 6 species of vetches, the exception was balanced nectar of <em>V. tetrasperma</em>.

Determination of Nectar Nicotine Concentration in N. attenuata

In this protocol, the determination of the nicotine concentration in nectar of Nicotiana attenuata is described. This method is applicable for the investigation of small amounts of nectar (above 1 μl). It is a high-throughput protocol optimized and streamlined for one skilled person to process approximately 100 nectar samples per day., 在该方案中，描述了烟草的花蜜中尼古丁浓度的测定。 这种方法适用于少量花蜜（高于1微升）的调查。 它是一种高通量协议，对于技术人员每天处理大约100种花蜜样品而言是优化的和简化的。

Nectar Production by InvasiveLantana camaraand EndemicL. peduncularisin the Galápagos Islands

Measurements of nectar volume and sugar concentration along two elevational gradients, in flower exclusion experiments, and over a diurnal cycle of nectar production were compared for invasive Lantana camara and endemic Lantana peduncularis in the Galapagos Islands during the dry season. Both species show the same pollination syndrome and are pollinated by Lepidoptera. Lantana camara flowers had a higher nectar volume than L. peduncularis flowers at every elevation and higher total sugar content. However, nectar in L. peduncularis flowers was much more concentrated than in L. camara flowers at lower elevations. The differences in nectar production between Lantana species seemed to be intrinsic and related to contrasting strategies to cope with drought. Nectar volume of unbagged flowers of L. camara was lower than that of bagged flowers at sunrise, which was probably related to consumption of nectar by nocturnal Lepidoptera. Nectar removal by floral visitors had a pronounced effect on total amount of nectar secreted by L. camara flowers but sugar concentration did not vary significantly. Our results suggest that L. camara may compete with L. peduncularis for pollinators.

Andromonoecy in an Old World Papilionoid legume, Erophaca baetica

Andromonoecy (i.e. the occurrence on individual plants of hermaphroditic and male flowers) is a rare sexual system among the angiosperms, regarded by some authors as a transitional stage from hermaphroditism to monoecy. Having discovered the occurrence of andromonoecy in Erophaca baetica (a Mediterranean shrubby legume with two subspecies), a novelty for Old World papilionoid legumes, we investigated the morpho-functional correlates and the geographical distribution of this phenomenon in the species. The relative frequencies of hermaphrodite and male flowers were determined in two field and 111 herbarium populations. Biomass allocation within flowers, pollen production and viability, pollen tube growth, nectar production and the temporal pattern of male flower production were also studied in two nearby southern Spanish populations. Virtually all of the studied populations were andromonoecious. Male flowers tended to appear at apical positions within the inflorescence, and became more abundant by the end of the flowering season. Male flowers were externally similar to hermaphroditic flowers (although with less biomass and smaller parts) and released equivalent amounts of pollen and nectar; however, their pollen germinated significantly better. Erophaca is the first example of an andromonecious Papilionoid in the Old World. Since the main difference among floral morphs in this species is functional (i.e. pollen germination rate) rather than morphological, andromonoecy is not readily noticeable, and very careful inspection may be required to reveal it. The potential effect of andromonoecy in enhancing outcrossing rate in this species is discussed.

Food selection by avian floral visitors: an important aspect of plant-flower visitor interactions in West Africa

Community-level studies have shown that plant–pollinator interactions are much more generalized than previously expected. Consequently, many authors have questioned the significance of phenotypic complementarity between plants and pollinators and abundance effects in pollination interactions. Here, we compare the behaviour of three sunbird species feeding on the nectar of five plant species in afromontane vegetation. We studied the feeding behaviour with and without consideration of plant abundance (i.e. diet selectivity and diet composition, respectively). The aims of the study were to estimate: (1) how relative resource abundance influences flower selectivity; (2) the degree of phenotypic matching; and (3) whether different plant resource assessment methods give different answers to this question. The results showed that, although sunbirds frequently feed on both morphologically adapted and nonadapted plants, food selectivity data are consistent with the hypothesis of phenotypic complementarity. Moreover, we found that the type of plant abundance measurement can change conclusions in some cases, as individual plants differ in their growth habits and nectar production. This effect was most obvious for the assessment of selectivity of the northern double-collared sunbird (Cinnyris reichenowi) and for Hypoestes aristata, a plant producing inflorescences composed of a large number of small flowers possessing small amounts of nectar per flower (a high abundance of flowers, but a low abundance of nectar relative to the remaining plant community).

Foraging rules of flower selection applied by colonies of Apis mellifera: ranking and associations of floral sources

Summary1. Interactions between bees and flowers are historically a key topic of research in biology. Apis mellifera is known to forage on a wide variety of flowers to collect nectar and/or pollen. Until now, resource collection strategies were investigated focusing on the influence of single factors on foraging decisions, such as hive requirements, surrounding vegetation, resource availability, seasonality and interactions with other bees. Despite the vast amount of literature on A. mellifera, we lack a comprehensive view of its flower selection.2. Our aim was to go beyond specific circumstances in order to identify general criteria for flower selection at species level. Applying data mining techniques (Market Basket Analysis), we found that bees exert a precise flower selection choice mainly driven by their pollen requirements. The bees foraged all over the study area with no obvious preference for the close surrounding vegetation. They selected a restricted number of all the available sources, for nectar as well as for pollen. Apis mellifera chose some floral sources more regularly than others. The most recurrent sources changed in time according to subsequent flowering peaks and often corresponded to anemophilous species. The compelling need for pollen revealed the constant demand of a few distinct floral sources. Plants providing huge quantities of pollen, such as wind‐pollinated species, were preferred. When the pollen source also provided a good quantity of nectar, foragers collected both resources on the same species.3. This work on A. mellifera helps to clarify some of the complex aspects of its floral selection processes, which emerge from studies on single colonies, areas or environmental factors influencing individual foraging behaviours. It also suggests that some established theories on pollinator–flower interactions, such as the role of wind‐pollinated species, need revision.