The relationship between nectar spur curvature in jewelweed (Impatiens capensis) and pollen removal by hummingbird pollinators

2003 ◽  
Vol 81 (2) ◽  
pp. 164-170 ◽  
Author(s):  
Steven E Travers ◽  
Ethan J Temeles ◽  
Irvin Pan
Keyword(s):  
Laboratory Experiments ◽  
Species Differences ◽  
Pollen Grains ◽  
Male Reproductive Success ◽  
Impatiens Capensis ◽  
Floral Nectar ◽  
Floral Diversity ◽  
Pollen Removal ◽  
The Relationship ◽  
Plant Pollinator

Floral nectar spurs are hypothesized to have had a major role in the evolution of floral diversity and plant-pollinator coadaptation. We examined variation in the degree of nectar spur curvature in two species of jewelweed (Impatiens capensis and Impatiens pallida) pollinated by different sets of pollinators. To distinguish between adaptive and nonadaptive explanations for between-species differences in curvature, we determined the relationship between spur curvature and pollen removal, which is one estimate of male reproductive success. Spur curvature exhibited considerable variation both within and among three populations, with spur angles ranging from 0° to 297°. A greenhouse experiment determined that spur curvature of I. capensis flowers has a broad-sense heritability of 0.636. Laboratory experiments indicated that flowers having recurved spurs deposit significantly more pollen grains on hummingbird visitors than flowers having perpendicular spurs, apparently as a result of greater contact between the androecium of curve-spurred flowers and the upper bill of hummingbirds. We also found a significant relationship between spur curvature and flower length, suggesting a developmental link between the two traits. We discuss the degree of spur curvature in bird-pollinated I. capensis as a function of both adaptive evolution and developmental constraint.Key words: pollination, nectar spurs, hummingbirds, Impatiens capensis, Impatiens pallida, pollen export, floral morphology, floral polymorphisms.

scholarly journals Comparison of Biochemical Constituents and Contents in Floral Nectar of Castanea spp.

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4225
Author(s):  
Young Ki Kim ◽  
Sujin Lee ◽  
Jeong Ho Song ◽  
Mahn Jo Kim ◽  
Ural Yunusbaev ◽  
...  
Keyword(s):  
Sugar Content ◽  
Amino Acid Content ◽  
Free Sugar ◽  
Floral Nectar ◽  
Volatile Organic ◽  
Male Flowers ◽  
Flower Visiting ◽  
The Relationship ◽  
Plant Pollinator ◽  
Japanese Cultivar

Pollination is essential for efficient reproduction in pollinator-dependent crops that rely on the attraction of pollinators to flowers. Especially, floral nectar is considered to be an important factor attracting pollinator like honey bees, but differences among major chestnut species (Castanea crenata, C. mollissima, C. dentata, and C. sativa) are still little explored. This study aims to evaluate the value of honey source by analyzing floral nectar characteristics and comparing the composition of volatile organic compounds (VOCs) that mediate plant-pollinator interaction. In this study, we analyzed nectar samples obtained from male flowers using HPLC and HS-SPME/GC–MS. The five chestnuts showed significant differences between the volume of secreted nectar, free sugar composition, amino acid content and VOCs composition. Furthermore, C. crenata (Japanese cultivar ‘Ungi’) was revealed to emit the highest total amounts of VOCs and high levels of benzenoid compounds that are generally associated with flower-visiting insects. The sugar content per catkin, which is used to determine the honey yield, was the highest in C. crenata, suggesting that C. crenata ‘Ungi’ can be highly valued as a honey tree. Therefore, a better understanding of the relationship between pollinator and nectar characteristics of C. crenara could contribute to a prospective honey plant.

Consistency of patterns between laboratory experiments and field collected fish in otolith chemistry: an example and applications for salinity reconstructions

2005 ◽  
Vol 56 (5) ◽  
pp. 609 ◽  
Author(s):  
T. S. Elsdon ◽  
B. M. Gillanders
Keyword(s):  
Environmental Variables ◽  
Laboratory Experiments ◽  
Juvenile Fish ◽  
Otolith Chemistry ◽  
Ambient Water ◽  
Elemental Concentrations ◽  
Adequate Knowledge ◽  
Black Bream ◽  
Environmental Histories ◽  
The Relationship

Elemental concentrations within fish otoliths can track movements and migrations of fish through gradients of environmental variables. Tracking the movements of fish relies on establishing links between environmental variables and otolith chemistry, with links commonly made using laboratory experiments that rear juvenile fish. However, laboratory experiments done on juvenile fish may not accurately reflect changes in wild fish, particularly adults. We tested the hypotheses that: (1) the relationship between ambient (water) and otolith chemistry is similar between laboratory-reared black bream (Acanthopagrus butcheri) and wild black bream; and (2) ontogeny does not influence otolith chemistry. Field-collected and laboratory-reared fish showed similar effects of ambient strontium : calcium (Sr : Ca) on otolith Sr : Ca concentrations. However, ambient and otolith barium : calcium concentrations (Ba : Ca) differed slightly between laboratory-reared and field-collected fish. Importantly, fish reared in stable environmental variables showed no influence of ontogeny on Sr : Ca or Ba : Ca concentrations. Natural distributions of ambient Sr : Ca showed no clear relationship to salinity, yet, ambient Ba : Ca was inversely related to salinity. The distribution of ambient Sr : Ca and Ba : Ca in estuaries inhabited by black bream, suggest that these elements can answer different questions regarding environmental histories of fish. Reconstructing salinity histories of black bream using otolith Ba : Ca concentrations seems plausible, if adequate knowledge of Ba : Ca gradients within estuaries is obtained.

scholarly journals Interactions Between Chill-Hours and Degree-Days Affect Carpogenic Germination in Monilinia vaccinii-corymbosi

2001 ◽  
Vol 91 (1) ◽  
pp. 77-83 ◽  
Author(s):  
H. Scherm ◽  
A. T. Savelle ◽  
P. L. Pusey
Keyword(s):  
Laboratory Experiments ◽  
Field Experiments ◽  
Degree Days ◽  
Carpogenic Germination ◽  
Conditioning Period ◽  
Low Degree ◽  
Heating Degree Days ◽  
Relationship Of ◽  
High Degree ◽  
The Relationship

The relationship of cumulative chill-hours (hours with a mean temperature <7.2°C) and heating degree-days (base 7.2°C) to carpogenic germination of pseudosclerotia of Monilinia vaccinii-corymbosi, which causes mummy berry disease of blueberry, was investigated. In two laboratory experiments, pseudosclerotia collected from rabbiteye blueberry in Georgia were conditioned at 5 to 6°C for 26 to 1,378 h prior to placement in conditions favorable for germination and apothecium development. The number of chill-hours accumulated during the conditioning period affected the subsequent proportion of pseudosclerotia that germinated and produced apothecia, with the greatest incidence of carpogenic germination occurring after intermediate levels of chilling (≈700 chill-hours). The minimum chilling requirement for germination and apothecium production was considerably lower than that reported previously for pseudo-sclerotia from highbush blueberry in northern production regions. The rate of carpogenic germination was strongly affected by interactions between the accumulation of chill-hours and degree-days during the conditioning and germination periods; pseudosclerotia exposed to prolonged chilling periods, once transferred to suitable conditions, germinated and produced apothecia more rapidly (after fewer degree-days had accumulated) than those exposed to shorter chilling periods. Thus, pseudosclerotia of M. vaccinii-corymbosi are adapted to germinate carpogenically following cold winters (high chill-hours, low degree-days) as well as warm winters (low chill-hours, high degree-days). Results were validated in a combined field-laboratory experiment in which pseudosclerotia that had received various levels of natural chilling were allowed to germinate in controlled conditions in the laboratory, and in two field experiments in which pseudosclerotia were exposed to natural chilling and germination conditions. A simple model describing the timing of apothecium emergence in relation to cumulative chill-hours and degree-days was developed based on the experiments. The model should be useful for better timing of field scouting programs for apothecia to aid in management of primary infection by M. vaccinii-corymbosi.

Self-Interested Giving: The Relationship Between Conditional Gifts, Charitable Donations, and Donor Self-Interestedness

2021 ◽  
Author(s):  
Matthew Chao ◽  
Geoffrey Fisher
Keyword(s):  
Decision Analysis ◽  
Experimental Evidence ◽  
Laboratory Experiments ◽  
Self Report ◽  
Negative Effects ◽  
Charitable Donations ◽  
Prosocial Motives ◽  
The Gift ◽  
Other Regarding ◽  
The Relationship

Nonprofits regularly use conditional “thank you” gifts to entice prospective donors to give, yet experimental evidence suggests that their effects are mixed in practice. This paper uses multiple laboratory experiments to test when and why thank you gifts vary in effectiveness. First, we demonstrate that although gifts often increase donations to charities that donors did not rate highly, many of the same gifts had no effects or negative effects for charities that prospective donors already liked. We replicate these findings in a second experiment that uses a different range of charity and gift options as well as different measures of participant perceptions of a charity. We also find that making gifts optional, as is common in fundraising campaigns, does not eliminate these negative gift effects. In additional experiments, we directly test for donor motives using self-report and priming experiments. We find that thank you gifts increase (decrease) the weight that donors place on self-interested (prosocial) motives, leading to changes in donation patterns. Altogether, our results suggest that practitioners may find gifts more useful when appealing to donors not already familiar with or favorably inclined to their charity, such as during donor acquisition campaigns. They may be less useful when appealing to recent donors or others who already favor the charity, in part because the gift may activate mindsets or norms that emphasize self-interested motives instead of more prosocial, other-regarding motives. This paper was accepted by Yan Chen, decision analysis.

scholarly journals Rape and the Prevalence of Hybrids in Broadly Sympatric Species: a Case Study using Albatrosses

2014 ◽  
Author(s):  
Sievert Rohwer ◽  
Rebecca B. Harris ◽  
Hollie E. Walsh
Keyword(s):  
Species Differences ◽  
Field Studies ◽  
Sympatric Species ◽  
Male Reproductive Success ◽  
Gene Exchange ◽  
Nuclear Markers ◽  
Mitochondrial Markers ◽  
Extensive Field

Conspecific rape often increases male reproductive success. However, the haste and aggression of forced copulations suggests that males may sometimes rape heterospecific females, thus making rape a likely, but undocumented, source of hybrids between broadly sympatric species. We present evidence that heterospecific rape may be the source of hybrids between Black-footed and Laysan Albatrosses (Phoebastria nigripes, and P. immutabilis, respectively). Extensive field studies have shown that paired (but not unpaired) males of both of these albatross species use rape as a supplemental reproductive strategy. Between species differences in size, timing of laying, and aggressiveness suggest that Black-footed Albatrosses should be more successful than Laysan Albatrosses in heteropspecific rape attempts, and male Black-footed Albatrosses have been observed attempting to force copulations on female Laysan Albatrosses. Nuclear markers showed that the six hybrids we studied were F1s and mitochondrial markers showed that male Black-footed Albatrosses sired all six hybrids. The siring asymmetry found in our hybrids may have long persisted because an IM analysis suggests that long-term gene exchange between these species has been from Black-footed Albatrosses into Laysan Albatrosses. If hybrids are sired in heterospecific rapes, they presumably would be raised and sexually imprinted on Laysan Albatrosses, and two unmated hybrids in a previous study courted only Laysan Albatrosses.

Species differences in altitude tolerance following X-irradiation

1960 ◽  
Vol 198 (4) ◽  
pp. 762-764 ◽  
Author(s):  
Bernard D. Newsom ◽  
Donald J. Kimeldorf
Keyword(s):  
Food Consumption ◽  
Guinea Pigs ◽  
Species Differences ◽  
Lethal Dose ◽  
Tolerance Test ◽  
Simulated Altitude ◽  
Hypoxic Tolerance ◽  
X Irradiation ◽  
Altitude Tolerance ◽  
The Relationship

The relationship between altitude tolerance and food consumption was investigated in irradiated and nonirradiated animals of several species. Food consumption was measured for 3 days following a mid-lethal dose of x-irradiation to assess the degree of postirradiation anorexia. Seventy-two hours after irradiation those animals, as well as ad libitum-fed and food-deprived nonirradiated animals were exposed to a simulated altitude tolerance test. The mortality produced in 4 hours was used as the criterion of hypoxic tolerance for each species. Irradiated rabbits and rats exhibited a severe decrease in food consumption and an increased hypoxic tolerance. Food consumption of mice was depressed during the 3 days following irradiation although the effect was much less than that observed for rats and rabbits. Guinea pigs and hamsters exhibited only a slight decrease in food consumption with recovery occurring after 24 hours. Mice, guinea pigs and hamsters did not exhibit a significant increase in hypoxic tolerance 3 days after radiation exposure. When nonirradiated rabbits, rats, mice and guinea pigs were food deprived, the hypoxic tolerance was significantly increased in all species.

A model-based approach for the analysis of aircraft seating comfort

Work ◽  
2021 ◽  
Vol 68 (s1) ◽  
pp. S251-S255
Author(s):  
Amalia Vanacore ◽  
Antonio Lanzotti ◽  
Chiara Percuoco ◽  
Agostino Capasso ◽  
Bonaventura Vitolo
Keyword(s):  
Data Analysis ◽  
Laboratory Experiments ◽  
Lumbar Region ◽  
User Characteristics ◽  
Model Based ◽  
Adopted Model ◽  
Comfort Perception ◽  
Seating Comfort ◽  
The Relationship ◽  
Data Analysis Methods

BACKGROUND: Aircraft seating comfort has a significant impact on passenger on-board experience. Its assessment requires the adoption of well-designed strategies for data collection as well as appropriate data analysis methods in order to obtain accurate and reliable results. OBJECTIVES: This paper focuses on the assessment of aircraft seating comfort based on subjective comfort responses collected during laboratory experiments and taking into account seat features and passenger characteristics. METHODS: The subjective comfort evaluations have been analyzed using a model-based approach to investigate the relationship between overall seating comfort and specific seat/user characteristics. RESULTS: The results show that the overall seating comfort perception is significantly influenced by the thickness of the seat pan, the backrest position (upright or reclined), the age of the passenger and the passenger perception of being comfortably supported at the lumbar region. CONCLUSIONS: The adopted model-based approach allows the analysis of subjective seating comfort data taking into account their ordinal nature as well as the dependency between evaluations provided by the same subject.

scholarly journals The Development of Snow and Glacier Research in Switzerland

1948 ◽  
Vol 1 (04) ◽  
pp. 192-201 ◽  
Author(s):  
R. Haefeli
Keyword(s):  
Mechanical Properties ◽  
Snow Cover ◽  
Laboratory Experiments ◽  
Relationship Of ◽  
The Relationship ◽  
Research Institute

The evolution of snow and glacier research in Switzerland is outlined. The settling, creep, viscosity and slipping of the snow cover are discussed in detail and the relationship of these comparatively simple processes to the more complex movements in a glacier are described. The importance of further research in glacier physics in connection with the crystallographic and mechanical properties of ice is stressed; certain preliminary laboratory experiments and some subjects for further research in the field are suggested. The Great Aletsch Glacier is recommended for this owing to the proximity of the Jungfraujoch Research Institute and facilities for transport by the Jungfraujoch Railway.

Annual Reproductive Yield in the Cooperative Pygmy Nuthatch (Sitta pygmaea)

The Auk ◽  
1988 ◽  
Vol 105 (1) ◽  
pp. 70-77 ◽  
Author(s):  
William J. Sydeman ◽  
Marcel Güntert ◽  
Russell P. Balda
Keyword(s):  
Reproductive Success ◽  
Cooperative Breeding ◽  
Reproductive Output ◽  
Breeding Birds ◽  
Overwinter Survival ◽  
Northern Arizona ◽  
Floral Diversity ◽  
Indirect Fitness ◽  
The Difference ◽  
The Relationship

Abstract We studied cooperative-breeding Pygmy Nuthatches (Sitta pygmaea) for 4 yr in northern Arizona. Breeding units contained 2-5 birds. Helpers were found at about 30% of all nests. All helpers that later bred on the study area were male. Helpers were mostly yearlings, and offspring or siblings of the birds that they aided, but often aided at least one unrelated breeder. Breeding units with helpers produced significantly more young than those without helpers. Breeding units in habitats with the greatest floral diversity and structural maturity fledged significantly more young than those in other habitats. Habitat did not influence the effect of helpers. Year effects increased the strength of the relationship between helpers and annual reproductive output. Previous breeding experience and pair-bond duration were not related to reproductive success. Total brood loss, although rare, was responsible for the difference in reproductive output among pairs with and without helpers and between habitats. Breeding birds with helpers benefit by an increase in direct fitness. The advantage to the helpers is not clear but may be an increase in indirect fitness associated with aiding relatives. Helpers may benefit directly, however, by sharing roosting cavities on a group territory thereby enhancing overwinter survival.

scholarly journals Novel Remanence Determination for Power Transformers Based on Magnetizing Inductance Measurements

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4616
Author(s):  
Chen Wei ◽  
Xianqiang Li ◽  
Ming Yang ◽  
Zhiyuan Ma ◽  
Hui Hou
Keyword(s):  
Numerical Simulations ◽  
Laboratory Experiments ◽  
Power Transformer ◽  
Power Transformers ◽  
Inrush Current ◽  
The Core ◽  
Novel Method ◽  
Simulation Results ◽  
Electro Magnetic ◽  
The Relationship

The remanence (residual flux) in the core of power transformers needs to be determined in advance to eliminate the inrush current during the process of re-energization. In this paper, a novel method is proposed to determine the residual flux based on the relationship between residual flux and the measured magnetizing inductance. The paper shows physical, numerical, and analytical explanations on the phenomenon that the magnetizing inductance decreases with the increase of residual flux under low excitation. Numerical simulations are performed by EMTP (Electro-Magnetic Transient Program) on a 1 kVA power transformer under different amounts of residual flux. The inductance–remanence curves are nearly the same when testing current changes. Laboratory experiments conducted on the same transformer are in line with the numerical simulations. Furthermore, numerical simulation results on a 240 MVA are reported to demonstrate the effectiveness of the proposed method.

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