The swift parrot Lathamus discolor (Psittacidae), social bees (Apidae), and native insects as pollinators of Eucalyptus globulus ssp. globulus (Myrtaceae)

2004 ◽  
Vol 52 (3) ◽  
pp. 371 ◽  
Author(s):  
A. B. Hingston ◽  
B. M. Potts ◽  
P. B. McQuillan
Keyword(s):  
Eucalyptus Globulus ◽  
Seed Set ◽  
Bombus Terrestris ◽  
Pollination Services ◽  
Social Bees ◽  
Single Flower ◽  
Fitness Benefits ◽  
The Cost ◽  
Effective Pollinator ◽  
Better Than

It has been argued that the production of sufficient nectar to attract bird pollinators would evolve if the fitness benefits accruing from pollination services by birds, compared with insects, outweighed the cost of increased allocation of photosynthate to nectar. This hypothesis implies that the pollination services provided by birds must be considerably better than those provided by insects with which the plant has evolved. Consistent with this, we found that the endangered native swift parrot Lathamus discolor (Shaw) was a very effective pollinator of the native tree Eucalyptus globulus Labill. in Tasmania, facilitating an average of 76% of the maximum possible seed set for open-pollinated flowers in just one visit to a flower, whereas single flower visits by native insects did not facilitate any seed production. Flowers visited once by either species of introduced social bees, the honeybee Apis mellifera L. or the bumblebee Bombus terrestris (L.), produced less than 7% of the maximum possible seed set for open-pollinated flowers. Hence, easily managed social bees appear to be poor substitutes for bird pollinators in commercial seed orchards of this tree. We propose three possible reasons why this largely bird-pollinated tree has not evolved characters that deter insects from removing nectar.

Pollination services provided by various size classes of flower visitors to Eucalyptus globulus ssp. globulus (Myrtaceae)

2004 ◽  
Vol 52 (3) ◽  
pp. 353 ◽  
Author(s):  
A. B. Hingston ◽  
B. M. Potts ◽  
P. B. McQuillan
Keyword(s):  
Seed Production ◽  
Eucalyptus Globulus ◽  
Seed Set ◽  
Pollen Limitation ◽  
Pollination Services ◽  
Flower Visitors ◽  
Large Numbers ◽  
Introduced Honeybee ◽  
Commercially Important ◽  
Almost All

Flowers of the commercially important tree Eucalyptus globulus Labill. ssp. globulus were visited by a wide variety of insects and birds within its natural distribution. Flowers were visited so frequently that most available nectar was consumed, but seed production within 5 m of the ground was consistently far less than the maximum possible, indicating the presence of large numbers of inefficient pollinators and few efficient pollinators. Pollen limitation was more severe on fully self-incompatible trees than on partially self-compatible trees, demonstrating that pollinator inefficiency resulted from infrequent outcrossing rather than inability to deposit pollen on stigmas. The flower visitors that were responsible for almost all nectar consumption from flowers within 5 m of the ground were insects that were able to permeate cages with 5-mm apertures but not cages with 1-mm apertures, the most abundant of which was the introduced honeybee Apis mellifera L. These insects contributed less than 20% of the maximum possible seed set, indicating that they were inefficient pollinators. Birds and smaller insects made lesser contributions to seed production, but consumed little nectar within 5 m of the ground. However, anthophilous birds appeared to mostly forage higher in the trees and probably consumed more nectar from, and provided more pollination services to, flowers higher in the trees.

scholarly journals Differences in Pollination Efficiency Among Three Bee Species in a Greenhouse and Their Effects on Yield and Fruit Quality of Northern Highbush ‘Bluecrop’ Blueberry

HortScience ◽  
2021 ◽  
pp. 1-5
Author(s):  
Qi Sun ◽  
Xingnan Zhao ◽  
Lei Wu ◽  
Jimin Zhao ◽  
Yunfei Yang ◽  
...  
Keyword(s):  
Fruit Quality ◽  
Seed Set ◽  
Bombus Terrestris ◽  
Apis Cerana ◽  
Pollen Deposition ◽  
Pollination Efficiency ◽  
Single Flower ◽  
Flower Visiting ◽  
Visiting Time

Different pollinators exhibit different adaptability to plants. Here, we compared the performance in visiting frequency and pollination efficiency among three bee pollinators (Bombus terrestris, Apis cerana, and Apis mellifera) on greenhouse-grown northern highbush ‘Bluecrop’ blueberry plants and evaluate their effects on yield and fruit quality. Our results indicated that the duration of daily flower-visiting of B. terrestris was 24 and 64 minutes longer than that of A. cerana and A. mellifera, respectively, and the visiting time of a single flower for B. terrestris was substantially shorter than the other two bee species, and pollen deposition on the stigma from single visit by B. terrestris was twice and three times that of A. cerana and A. mellifera, respectively. The yield of individual plants pollinated by B. terrestris showed an increase of 11.4% and 20.0% compared with the plants pollinated by A. cerana and A. mellifera, respectively, with the rate of Grade I fruit (>18 mm diameter) reaching 50.8%, compared with 32.9% and 22.5% for A. cerana and A. mellifera groups, respectively. Moreover, the early-to-midseason yield of plants pollinated by B. terrestris was higher, and the ripening time was 3 to 4 days earlier. An artificial pollination experiment demonstrated that seed set of high (≈300), medium (90–110), and low (20–30) pollination amounts were 43.0%, 42.5%, and 10.5%, respectively, and the corresponding mean weights of single fruits (related to the seed number inside) were 2.8, 2.7, and 1.2 g, respectively. The highly efficient pollination of B. terrestris was attributed to its behavior of buzz-pollination. Therefore, it is preferential for pollination of ‘Bluecrop’ blueberry in the greenhouse.

scholarly journals Diverse pollinator communities enhance plant reproductive success

2012 ◽  
Vol 279 (1748) ◽  
pp. 4845-4852 ◽  
Author(s):  
Matthias Albrecht ◽  
Bernhard Schmid ◽  
Yann Hautier ◽  
Christine B. Müller
Keyword(s):  
Species Richness ◽  
Reproductive Success ◽  
Seed Set ◽  
Population Level ◽  
Solitary Bees ◽  
Pollination Services ◽  
Niche Complementarity ◽  
Social Bees ◽  
Pollinator Diversity ◽  
Pollinator Community

Understanding the functional consequences of biodiversity loss is a major goal of ecology. Animal-mediated pollination is an essential ecosystem function and service provided to mankind. However, little is known how pollinator diversity could affect pollination services. Using a substitutive design, we experimentally manipulated functional group (FG) and species richness of pollinator communities to investigate their consequences on the reproductive success of an obligate out-crossing model plant species, Raphanus sativus . Both fruit and seed set increased with pollinator FG richness. Furthermore, seed set increased with species richness in pollinator communities composed of a single FG. However, in multiple-FG communities, highest species richness resulted in slightly reduced pollination services compared with intermediate species richness. Our analysis indicates that the presence of social bees, which showed roughly four times higher visitation rates than solitary bees or hoverflies, was an important factor contributing to the positive pollinator diversity–pollination service relationship, in particular, for fruit set. Visitation rate at different daytimes, and less so among flower heights, varied among social bees, solitary bees and hoverflies, indicating a niche complementarity among these pollinator groups. Our study demonstrates enhanced pollination services of diverse pollinator communities at the plant population level and suggests that both the niche complementarity and the presence of specific taxa in a pollinator community drive this positive relationship.

scholarly journals Telecom Churn Prediction System Based on Ensemble Learning Using Feature Grouping

2021 ◽  
Vol 11 (11) ◽  
pp. 4742
Author(s):  
Tianpei Xu ◽  
Ying Ma ◽  
Kangchul Kim
Keyword(s):  
Ensemble Learning ◽  
Machine Learning Algorithms ◽  
Customer Relationship ◽  
Prediction System ◽  
Churn Prediction ◽  
Customer Churn ◽  
Feature Grouping ◽  
Recognition Systems ◽  
The Cost ◽  
Better Than

In recent years, the telecom market has been very competitive. The cost of retaining existing telecom customers is lower than attracting new customers. It is necessary for a telecom company to understand customer churn through customer relationship management (CRM). Therefore, CRM analyzers are required to predict which customers will churn. This study proposes a customer-churn prediction system that uses an ensemble-learning technique consisting of stacking models and soft voting. Xgboost, Logistic regression, Decision tree, and Naïve Bayes machine-learning algorithms are selected to build a stacking model with two levels, and the three outputs of the second level are used for soft voting. Feature construction of the churn dataset includes equidistant grouping of customer behavior features to expand the space of features and discover latent information from the churn dataset. The original and new churn datasets are analyzed in the stacking ensemble model with four evaluation metrics. The experimental results show that the proposed customer churn predictions have accuracies of 96.12% and 98.09% for the original and new churn datasets, respectively. These results are better than state-of-the-art churn recognition systems.

The Race for Online Reputation: Implications for Platforms, Firms, and Consumers

2021 ◽  
Author(s):  
Mingwen Yang ◽  
Zhiqiang (Eric) Zheng ◽  
Vijay Mookerjee
Keyword(s):  
Adverse Event ◽  
Marketing Mix ◽  
Digital Economy ◽  
The Other ◽  
The Mean ◽  
The Absolute ◽  
The Cost ◽  
Online Reputation ◽  
Better Than

Online reputation has become a key marketing-mix variable in the digital economy. Our study helps managers decide on the effort they should use to manage online reputation. We consider an online reputation race in which it is important not just to manage the absolute reputation, but also the relative rating. That is, to stay ahead, a firm should try to have ratings that are better than those of its competitors. Our findings are particularly significant for platform owners (such as Expedia or Yelp) to strategically grow their base of participating firms: growing the middle of the market (firms with average ratings) is the best option considering the goals of the platform and the other stakeholders, namely incumbents and consumers. For firms, we find that they should increase their effort when the mean market rating increases. Another key insight for firms is that, sometimes, adversity can come disguised as an opportunity. When an adverse event strikes the industry (such as a reduction in sales margin or an increase in the cost of effort), a firm’s profit can increase if it can manage this event better than its competitors.

What money can’t buy: an argument against paying people to get vaccinated

2021 ◽  
pp. medethics-2021-107235
Author(s):  
Nancy S Jecker
Keyword(s):  
Best Practices ◽  
Economic Conditions ◽  
Vaccine Hesitancy ◽  
Short Term ◽  
Healthy Communities ◽  
Good Citizenship ◽  
Mutant Strains ◽  
The Cost ◽  
Better Than

This paper considers the proposal to pay people to get vaccinated against the SARS-CoV-2 virus. The first section introduces arguments against the proposal, including less intrusive alternatives, unequal effects on populations and economic conditions that render payment more difficult to refuse. The second section considers arguments favouring payment, including arguments appealing to health equity, consistency, being worth the cost, respect for autonomy, good citizenship, the ends justifying the means and the threat of mutant strains. The third section spotlights long-term and short-term best practices that can build trust and reduce ‘vaccine hesitancy’ better than payment. The paper concludes that people who, for a variety of reasons, are reluctant to vaccinate should be treated like adults, not children. Despite the urgency of getting shots into arms, we should set our sights on the long-term goals of strong relationships and healthy communities.

Evaluation of the anti-diabetic activities of crude extracts of Annona muricata and Rutidea parviflora in alloxan-diabetic rats

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
OR Johnson-Ajinwo ◽  
◽  
Kuebari Penuel Berebari ◽  
Keyword(s):  
Diabetic Rats ◽  
Maximum Activity ◽  
Root Bark ◽  
Synergistic Activity ◽  
Annona Muricata ◽  
Activity Maximum ◽  
Chronic Hyperglycemia ◽  
Organic Extracts ◽  
The Cost ◽  
Better Than

Background: Diabetes Mellitus (DM), is a malignant disease that has impacted the globe in astronomical proportions. Chronic hyperglycemia is a major condition suffered by patients with DM. Currently, the cost of managing DM is highly exorbitant and poses a significant obstacle to many living with the disease in developing countries. Thus, the need for affordable alternatives with optimum potency and minimal side effects is justified. Historically, Annona muricata is one plant that is used in the treatment of DM and a host of other ailments. Rutidea parviflora has been used in combination with other plants in the treatment of DM by some ethnic groups. The aim of this study is to investigate the anti-diabetic activities of these plants. Method: The anti-diabetic activities of aqueous and organic extracts of Annona muricata (leaves), and Rutidea parviflora (root bark) at 200 mg/kg and 400 mg/kg, were screened for their anti-diabetic activities in normoglycemic and alloxan-induced diabetic rats (150-200 g) at 1h, 2h, 4h, 6h, 8h, and the 12th hour. DMSO (0.3 ml of 33.3% v/v stock) and Glibenclamide 10 mg/kg were administered to the control and reference groups respectively. Result: Organic extracts of A. muricata at 400 mg/kg significantly decreased FBGL in both normoglycemic and hyperglycemic groups by 65.9% and 62.1% respectively (P<0.05). R. parviflora leaves extracts showed less activity. However, it had relatively short acting activity (maximum activity at the 4th hour). In each case, the organic extracts performed better than the aqueous extracts. Conclusion: A. muricata has potentials for the treatment of DM, and merits further research to support the plant’s therapeutic application. R. parviflora may offer some beneficial effect, and possibly boost the potency of A. muricata by synergistic activity when co-administered.

scholarly journals Mobile Learning System for Egyptian Higher Education Using Agile-Based Approach

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Menna Elkhateeb ◽  
Abdulaziz Shehab ◽  
Hazem El-bakry
Keyword(s):  
Higher Education ◽  
Mobile Learning ◽  
Mobile Applications ◽  
Learning System ◽  
System Failure ◽  
Course Materials ◽  
Smart Mobile ◽  
The Cost ◽  
Mobile Learning System ◽  
Better Than

Nowadays, due to easiness and expansion in property of smart mobile devices, it is becoming inevitable for mobile applications to have an important role in higher education systems. The Egyptian public universities are facing the problem of students’ large number enrolled in each year. Thus, we lack proper communication between educators and learners. Mobile learning can solve that problem, and it enables adjustment of the curriculum to meet students' learning time and life situations. It provides different solutions better than traditional educational methods. Students and professors could exchange educational material or information even if they are not in the same class. Furthermore, the cost of universities’ materials reduced, as all course materials can be found online through mobile applications. This paper proposes a mobile learning system named “Easy-Edu.” The proposed system intended to make the learning process easier, focus on students’ needs, and encourage communication and collaboration between students and professors and supports collaborative scenario-based learning for university students. Unlike other traditional systems, the proposed “Easy-Edu” was built using an Agile-based approach that delivers sustainable and high-quality mobile learning system. In addition, it eliminates the chances of absolute system failure and detects and fixes issues faster. Summarily, everything related to the design and implementation of “Easy-Edu” is discussed.

Lactate-to-pyruvate or pyruvate-to-lactate assay for lactate dehydrogenase: a re-examination.

1979 ◽  
Vol 25 (2) ◽  
pp. 269-272 ◽  
Author(s):  
B F Howell ◽  
S McCune ◽  
R Schaffer
Keyword(s):  
Lactate Dehydrogenase ◽  
Reference Material ◽  
Standard Reference Material ◽  
National Bureau ◽  
The Cost ◽  
Better Than

Abstract The pyruvate-to-lactate assay for determining lactate dehydrogenase (EC 1.1.1.27) can now yield linearity equal to or better than that obtained by the lactate-to-pyruvate assay. In addition, there are significant advantages to the pyruvate-to-lactate reaction: (a) a greater change in absorbance per unit time, which allows more accurate spectrophotometric readout; (b) lower reactant concentrations are required, which substantially reduces the cost per assay; (c) solid reagents are used to prepare the assay solution; and (d) reagent solutions are more stable. However, impurities present in commercial NADH preparations may substantially affect measured lactated dehydrogenase activities; therefore, a Standard Reference Material for NADH is being developed for issuance by the National Bureau of Standards.

scholarly journals Pollen adaptation to ant pollination: a case study from the Proteaceae

2020 ◽  
Vol 126 (3) ◽  
pp. 377-386 ◽  
Author(s):  
Nicola Delnevo ◽  
Eddie J van Etten ◽  
Nicola Clemente ◽  
Luna Fogu ◽  
Evelina Pavarani ◽  
...  
Keyword(s):  
Seed Set ◽  
Germination Rate ◽  
Pollen Grains ◽  
Relative Effect ◽  
The Other ◽  
Pollen Load ◽  
Pollination Services ◽  
Ant Pollination ◽  
Negative Effect ◽  
Floral Visitors

Abstract Background and Aims Ant–plant associations are widely diverse and distributed throughout the world, leading to antagonistic and/or mutualistic interactions. Ant pollination is a rare mutualistic association and reports of ants as effective pollinators are limited to a few studies. Conospermum (Proteaceae) is an insect-pollinated genus well represented in the south-western Australia biodiversity hotspot, and here we aimed to evaluate the role of ants as pollinators of C. undulatum. Methods Pollen germination after contact with several species of ants and bees was tested for C. undulatum and five co-flowering species for comparison. We then sampled the pollen load of floral visitors of C. undulatum to assess whether ants carried a pollen load sufficient to enable pollination. Lastly, we performed exclusion treatments to assess the relative effect of flying- and non-flying-invertebrate floral visitors on the reproduction of C. undulatum. For this, we measured the seed set under different conditions: ants exclusion, flying-insects exclusion and control. Key Results Pollen of C. undulatum, along with the other Conospermum species, had a germination rate after contact with ants of ~80 % which did not differ from the effect of bees; in contrast, the other plant species tested showed a drop in the germination rate to ~10 % following ant treatments. Although ants were generalist visitors, they carried a pollen load with 68–86 % of suitable grains. Moreover, ants significantly contributed to the seed set of C. undulatum. Conclusions Our study highlights the complexity of ant–flower interactions and suggests that generalizations neglecting the importance of ants as pollinators cannot be made. Conospermum undulatum has evolved pollen with resistance to the negative effect of ant secretions on pollen grains, with ants providing effective pollination services to this threatened species.

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