scholarly journals Patch Departure Behavior of Bumble Bees: Rules and Mechanisms

2010 ◽  
Vol 2010 ◽  
pp. 1-9
Author(s):  
Dale E. Taneyhill
Keyword(s):  
Foraging Behavior ◽  
Sucrose Solution ◽  
Field Tests ◽  
Threshold Level ◽  
Cognitive Models ◽  
Bumble Bees ◽  
Dynamic Threshold ◽  
Floral Nectar ◽  
Nectar Volume ◽  
Departure Behavior

I present an increment-decay model for the mechanism of bumble bees' decision to depart from inflorescences. The probability of departure is the consequence of a dynamic threshold level of stimuli necessary to elicit a stereotyped landing reaction. Reception of floral nectar lowers this threshold, making the bee less likely to depart. Concurrently the threshold increases, making departure from the inflorescence more probable. Increments to the probability of landing are an increasing, decelerating function of nectar volume, and are worth less, in sequence, for the same amount of nectar. The model is contrasted to threshold departure rules, which predict that bees will depart from inflorescences if the amount of nectar in the last one or two flowers visited is below a given level. Field tests comparing the two models were performed with monkshood (Aconitum columbianum). Treated flowers contained a descending series of nectar volumes (6 to 0 L of 30 % sucrose solution). The more nectar that bees encountered in the treated flowers, the more likely they were to remain within the inflorescence after subsequently visiting one to three empty flowers. I discuss the differences between rules and mechanisms in regard to cognitive models of foraging behavior.

scholarly journals Adding Amino Acids to a Sucrose Diet Is Not Sufficient to Support Longevity of Adult Bumble Bees

Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 247 ◽  
Author(s):  
Nils Grund-Mueller ◽  
Fabian A. Ruedenauer ◽  
Johannes Spaethe ◽  
Sara D. Leonhardt
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Bombus Terrestris ◽  
Sucrose Solution ◽  
Amino Acid Content ◽  
Well Being ◽  
Nutritional Composition ◽  
Nutrient Composition ◽  
Bumble Bees ◽  
Essential Amino Acid Content

Dietary macro-nutrients (i.e., carbohydrates, protein, and fat) are important for bee larval development and, thus, colony health and fitness. To which extent different diets (varying in macro-nutrient composition) affect adult bees and whether they can thrive on nectar as the sole amino acid source has, however, been little investigated. We investigated how diets varying in protein concentration and overall nutrient composition affected consumption, longevity, and breeding behavior of the buff-tailed bumble bee, Bombus terrestris (Hymenoptera: Apidae). Queenless micro-colonies were fed either natural nutrient sources (pollen), nearly pure protein (i.e., the milk protein casein), or sucrose solutions with low and with high essential amino acid content in concentrations as can be found in nectar. We observed micro-colonies for 110 days. We found that longevity was highest for pure pollen and lowest for pure sucrose solution and sucrose solution supplemented with amino acids in concentrations as found in the nectar of several plant species. Adding higher concentrations of amino acids to sucrose solution did only slightly increase longevity compared to sucrose alone. Consequently, sucrose solution with the applied concentrations and proportions of amino acids or other protein sources (e.g., casein) alone did not meet the nutritional needs of healthy adult bumble bees. In fact, longevity was highest and reproduction only successful in micro-colonies fed pollen. These results indicate that, in addition to carbohydrates and protein, adult bumble bees, like larvae, need further nutrients (e.g., lipids and micro-nutrients) for their well-being. An appropriate nutritional composition seemed to be best provided by floral pollen, suggesting that pollen is an essential dietary component not only for larvae but also for adult bees.

scholarly journals Salvage of floral resources through re-absorption before flower abscission

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Graham H. Pyke ◽  
Zong-Xin Ren ◽  
Judith Trunschke ◽  
Klaus Lunau ◽  
Hong Wang
Keyword(s):  
Floral Resources ◽  
Floral Nectar ◽  
Nectar Volume ◽  
Flower Colours ◽  
Nectar Concentration ◽  
Nectar Sugar ◽  
Biochemical Mechanisms ◽  
Floral Resource ◽  
Almost All

Abstract Plants invest floral resources, including nectar and pigment, with likely consequent reproductive costs. We hypothesized that plants, whose flowers abscise with age, reabsorb nectar and pigment before abscission. This was tested with flowers of Rhododendron decorum, which has large, conspicuous white flowers that increasingly abscise corollas as flowers age. As this species is pollinated by bees, we also hypothesized that nectar concentration would be relatively high (i.e., > 30% wt/vol) and petals would contain UV-absorbing pigment. Floral nectar volume and concentration were sampled on successive days until abscission (up to ten days old, peak at five days) and for sub-sample of four-day-old flowers. Flowers just abscised were similarly sampled. Flower colours were measured using a modified camera, with recordings of spectral reflectance for abscised and open non-abscised flowers. Pigment content was summed values of red, green, blue channels of false color photos. As expected, flowers reabsorbed almost all nectar before abscission, separately reabsorbing nectar-sugar and nectar-water, and petals contained UV-absorbing pigment. However, flowers did not reabsorb pigment and nectar-concentration was < 30% wt/vol. That flowers reabsorb nectar, not pigment, remains unexplained, though possibly pigment reabsorption is uneconomical. Understanding floral resource reabsorption therefore requires determination of biochemical mechanisms, plus costs/benefits for individual plants.

scholarly journals Variation in Nectar Volume and Sugar Concentration ofAllium ursinumL. ssp.ucrainicumin Three Habitats

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Ágnes Farkas ◽  
Réka Molnár ◽  
Tamás Morschhauser ◽  
István Hahn
Keyword(s):  
Soil Properties ◽  
Brown Forest Soil ◽  
Full Bloom ◽  
Floral Nectar ◽  
Nectar Production ◽  
Nectar Volume ◽  
Sessile Oak ◽  
Microclimatic Conditions ◽  
The Difference

Floral nectar volume and concentration of ramson (Allium ursinumL. ssp.ucrainicum) were investigated in three different habitats, including two types of sessile oak-hornbeam association on brown forest soil with clay illuviation and a silver lime-flowering ash rock forest association on rendzina. Daily nectar production ranged from 0.1 to 3.8 μL per flower with sugar concentrations of 25 to 50%. Mean nectar volumes and concentrations showed significant differences between freely exposed flowers and covered flowers, which had been isolated from flower visitors 24 h prior to nectar studies. Both the amount and quality of nectar were affected by microclimatic conditions and soil properties and varied between populations at different habitats. In the silver lime-flowering ash rock-forest association mean nectar volumes and concentrations were lower than in a typical sessile oak-hornbeam association on three occasions, the difference being significant in two cases. During full bloom, the date of sampling did not have a profound effect on either nectar volume or concentration.

scholarly journals Dracula’s mistress: removal of blood-red floral nectar results in secretion of more nectar

2020 ◽  
Vol 153 (1) ◽  
pp. 59-66
Author(s):  
Thomas Mione ◽  
Isaac Argeo Diaz
Keyword(s):  
Sugar Content ◽  
Total Sugar ◽  
Sugar Production ◽  
Floral Nectar ◽  
Nectar Production ◽  
Total Sugar Content ◽  
Nectar Volume ◽  
Floral Nectary ◽  
Floral Longevity ◽  
Nectar Replenishment

Background and aims – Flowers of Jaltomata quipuscoae (Solanaceae) secrete blood-red nectar that serves as an energy reward and possible attractant to pollinators. The purposes of this study were to determine whether simulated pollinator visits (manual removal of nectar) stimulates replenishment of nectar, and report the pattern of nectar presentation during the lifespan of the flower. Methods – For the nectar replenishment experiments flowers were paired: each pair of flowers was selected to be on the same plant and at the same developmental stage. From all 62 flowers nectar was removed and discarded (not measured) at time zero. Then, over a period of eight hours, the nectar of one flower was measured four times, i.e., every two hours, while nectar of the paired control flower was measured only at the end of the eight-hour period. In the nectar dynamics experiment five sets of flowers received different treatments: flowers were unmanipulated for zero, one, two, three or four days and then nectar was removed once every day. The volume of nectar produced and concentration of sugar in the nectar were recorded at each extraction for both studies.Key results – In the nectar replenishment study significantly higher nectar volume and consequently significantly higher total sugar content was present in the experimental nectar-extracted flowers. In the nectar dynamics study, nectar was produced starting on day one or two, continuously through the life of the open flowers until one or two days before the corolla senesced. Delay of nectar removal from different flower sets for zero, one, two, three or four days resulted in a linear increase in nectar volume and total nectar sugar production, and had little or no effect on the cumulative (life of the flower) nectar production. Floral longevity, seven to ten days, was not affected by a single removal of nectar each day.Conclusions – The floral nectary of J. quipuscoae responded to nectar removal by secreting more nectar, and thus more total sugar (not a higher concentration of sugar) than was secreted by control flowers. In flowers from which nectar was not removed, nectar volume and thus total sugar secreted continued to accumulate linearly, suggesting that reabsorption of nectar either does not occur or is slow relative to the rate of secretion. The more we (or pollinators) take, the more the flowers make: the volume of nectar and sugar production increase if nectar is removed frequently but not if nectar is removed infrequently.

Rewards 2: The Biology of Nectar

2011 ◽  
Author(s):  
Pat Willmer
Keyword(s):  
Chemical Composition ◽  
Nectar Secretion ◽  
Water Reward ◽  
Floral Nectar ◽  
Nectar Production ◽  
Nectar Volume ◽  
Floral Reward ◽  
Nectar Concentration

This chapter examines the biology of nectar, the main secondary floral reward in an evolutionary sense. As a commodity, nectar is easy for plants to produce and easy for animals to handle; its sugars are simple to metabolize and thus to use as a readily available fuel for an animal’s activities. Nectar is a crucial factor in determining the interactions of flowers and their visitors. The chapter first provides an overview of how floral nectar is produced in a nectary before discussing nectar secretion, the chemical composition of nectar, and nectar volume. It then considers nectar concentration and viscosity, nectar as a sugar and energy reward, and nectar as a water reward. It also explores daily, seasonal, and phylogenetic patterns of nectar production, how flowers control their nectar and their pollinators, and problems in measuring and quantifying nectar. The chapter concludes with an analysis of the costs of nectar gathering.

scholarly journals Microbial communities in hummingbird feeders are distinct from floral nectar and influenced by bird visitation

2019 ◽  
Vol 286 (1898) ◽  
pp. 20182295 ◽  
Author(s):  
Casie Lee ◽  
Lisa A. Tell ◽  
Tiffany Hilfer ◽  
Rachel L. Vannette
Keyword(s):  
Microbial Communities ◽  
Pathogenic Bacteria ◽  
Sucrose Solution ◽  
Microbial Populations ◽  
Floral Nectar ◽  
Solution Ph ◽  
Microbial Composition ◽  
Ascomycete Fungi ◽  
Bacteria And Fungi ◽  
Free Ranging

Human provisioning can shape resource availability for wildlife, but consequences for microbiota availability and exchange remain relatively unexplored. Here, we characterized microbial communities on bills and faecal material of hummingbirds and their food resources, including feeders and floral nectar. We experimentally manipulated bird visitation to feeders and examined effects on sucrose solution microbial communities. Birds, feeders and flowers hosted distinct bacterial and fungal communities. Proteobacteria comprised over 80% of nectar bacteria but feeder solutions contained a high relative abundance of Proteobacteria, Firmicutes and Actinobacteria. Hummingbirds hosted bacterial taxa commonly found in other birds and novel genera including Zymobacter [Proteobacteria] and Ascomycete fungi. For feeders, bird-visited and unvisited solutions both accumulated abundant microbial populations that changed solution pH, but microbial composition was largely determined by visitation treatment. Our results reveal that feeders host abundant microbial populations, including some bird-associated microbial taxa. Microbial taxa in feeders were primarily non-pathogenic bacteria and fungi but differed substantially from those in floral nectar. These results demonstrate that human provisioning influences microbial intake by free-ranging hummingbirds; however, it is unknown how these changes impact hummingbird gastrointestinal flora or health.

scholarly journals Variable effects of nicotine and anabasine on parasitized bumble bees

F1000Research ◽  
2015 ◽  
Vol 4 ◽  
pp. 880 ◽  
Author(s):  
Lukas P. Thorburn ◽  
Lynn S. Adler ◽  
Rebecca E. Irwin ◽  
Evan C. Palmer-Young
Keyword(s):  
Secondary Metabolites ◽  
Environmental Conditions ◽  
Synergistic Effects ◽  
Parasite Load ◽  
Bumble Bees ◽  
Interactive Effects ◽  
Constant Darkness ◽  
Floral Nectar ◽  
Antagonistic Interaction ◽  
Crithidia Bombi

Secondary metabolites in floral nectar have been shown to reduce parasite load in two common bumble bee species. Previous studies on the effects of nectar secondary metabolites on parasitized bees have focused on single compounds in isolation; however, in nature, bees are simultaneously exposed to multiple compounds. We tested for synergistic effects of two alkaloids found in the nectar of Nicotiana spp. plants, nicotine and anabasine, on parasite load and mortality in bumble bees (Bombus impatiens) infected with the intestinal parasite Crithidia bombi. Adult worker bees inoculated with C. bombi were fed nicotine and anabasine diet treatments in a factorial design, resulting in four nectar treatment combinations:  2 ppm nicotine, 5 ppm anabasine, 2ppm nicotine and 5 ppm anabasine together, or a control alkaloid-free solution. We conducted the experiment twice: first, with bees incubated under variable environmental conditions (‘Variable’; temperatures varied from 10-35°C); and second, under carefully controlled environmental conditions (‘Controlled’; 27°C incubator, constant darkness). In ‘Variable’, each alkaloid alone significantly decreased parasite loads, but this effect was not realized with the alkaloids in combination, suggesting an antagonistic interaction. Nicotine but not anabasine significantly increased mortality, and the two compounds had no interactive effects on mortality. In ‘Controlled’, nicotine significantly increased parasite loads, the opposite of its effect in ‘Variable’. While not significant, the relationship between anabasine and parasite loads was also positive. Interactive effects between the two alkaloids on parasite load were non-significant, but the pattern of antagonistic interaction was similar to that in the variable experiment. Neither alkaloid, nor their interaction, significantly affected mortality under controlled conditions. Our results do not indicate synergy between Nicotiana nectar alkaloids; however, they do suggest a complex interaction between secondary metabolites, parasites, and environmental variables, in which secondary metabolites can be either toxic or medicinal depending on context.

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