Motion discrimination by Bombus impatiens (Hymenoptera: Apidae)

2015 ◽  
Vol 147 (5) ◽  
pp. 580-591 ◽  
Author(s):  
Hamida B. Mirwan ◽  
Peter G. Kevan
Keyword(s):  
Pollen Dispersal ◽  
Bombus Impatiens ◽  
Artificial Flower ◽  
Motion Discrimination ◽  
En Face ◽  
Better Than

AbstractMobility of flowers in the wind has been proposed to affect the performances of pollinators in landing on flowers, nectar extraction, and pollen dispersal. Our study examined the preferences of worker Bombus impatiens Cresson (Hymenoptera: Apidae) for landing on and feeding from immobile or mobile artificial flower. Mobile flowers moved at varied frequencies (0.1–3.0 Hz) and in different directions, horizontal H (left to right wave) and vertical V (from en-face presentation at the lowest point to horizontal presentation at the zenith). We found that the bees showed no preference for mobile or immobile flowers. In general, we found that landing ability (time spent from the bees entering the testing arena to landing and starting to feed on the artificial flower) decreased as frequency (Hz) or speed of motion (cm/second) increased. Directionality of waving affected performance with the bees being able to forage from horizontally moving flowers better than from vertically moving flowers. Experience played a major role in improving individual performances. We also found that the bees could differentiate between horizontally and vertically waving flowers as well as between frequencies or speeds of motion.

Mirror Image Pattern Matching By Bumble Bees

Behaviour ◽  
1995 ◽  
Vol 132 (1-2) ◽  
pp. 87-93 ◽  
Author(s):  
C.M.S. Plowright ◽  
Y.G. Korneluk
Keyword(s):  
Pattern Matching ◽  
Honey Bees ◽  
Mirror Image ◽  
Bumble Bees ◽  
Bombus Impatiens ◽  
Artificial Flower ◽  
Choice Tests ◽  
Image Transformations ◽  
Image Pattern

AbstractBumble bees (Bombus impatiens) were trained to discriminate between a rewarding and non-rewarding artificial flower that differed only in their configuration of four identical petals. On choice tests between 2 empty flowers, the bees chose the flower with the configuration of the rewarding flower over the mirror image, but the mirror image over a novel flower. This behaviour is the same as has been observed with honey bees and functional interpretations are considered. The problem of distinguishing between left-right pattern reversals and true mirror image transformations is discussed.

Spatial encoding by bumblebees (Bombus impatiens) of a reward within an artificial flower array

2006 ◽  
Vol 9 (2) ◽  
pp. 131-140 ◽  
Author(s):  
Dana L. Church ◽  
Catherine M. S. Plowright
Keyword(s):  
Bombus Impatiens ◽  
Spatial Encoding ◽  
Artificial Flower

scholarly journals Two-Generation Analysis of Pollen Flow Across a Landscape. IV. Estimating the Dispersal Parameter

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 355-363
Author(s):  
Frédéric Austerlitz ◽  
Peter E Smouse
Keyword(s):  
Adult Population ◽  
Pollen Dispersal ◽  
Dispersal Distance ◽  
The Novel ◽  
Sample Sizes ◽  
Plant Populations ◽  
Global Estimate ◽  
Independent Estimate ◽  
Pollen Movement ◽  
Better Than

Abstract The distance of pollen movement is an important determinant of the neighborhood area of plant populations. In earlier studies, we designed a method for estimating the distance of pollen dispersal, on the basis of the analysis of the differentiation among the pollen clouds of a sample of females, spaced across the landscape. The method was based solely on an estimate of the global level of differentiation among the pollen clouds of the total array of sampled females. Here, we develop novel estimators, on the basis of the divergence of pollen clouds for all pairs of females, assuming that an independent estimate of adult population density is available. A simulation study shows that the estimators are all slightly biased, but that most have enough precision to be useful, at least with adequate sample sizes. We show that one of the novel pairwise methods provides estimates that are slightly better than the best global estimate, especially when the markers used have low exclusion probability. The new method can also be generalized to the case where there is no prior information on the density of reproductive adults. In that case, we can jointly estimate the density itself and the pollen dispersal distance, given sufficient sample sizes. The bias of this last estimator is larger and the precision is lower than for those estimates based on independent estimates of density, but the estimate is of some interest, because a meaningful independent estimate of the density of reproducing individuals is difficult to obtain in most cases.

How many flower types can bumble bees work at the same time?

1998 ◽  
Vol 76 (7) ◽  
pp. 1358-1365 ◽  
Author(s):  
R J Gegear ◽  
T M Laverty
Keyword(s):  
Plant Species ◽  
Foraging Behaviour ◽  
Bumble Bees ◽  
Bombus Impatiens ◽  
Interference Effects ◽  
Artificial Flower ◽  
Different Types ◽  
Flower Type ◽  
A Minor ◽  
Flower Handling

Bumble bees often restrict their foraging behaviour to the flowers of two plant species on a single foraging trip ("a major and a minor" sensu Heinrich), perhaps because learning additional flower-handling techniques interferes with their ability to recall previously learned flower-handling skills. This hypothesis was tested with bumble bees (Bombus impatiens) foraging on arrays of artificial flower types. Test bees were first trained on one flower type, then retested on the same flower type after learning one, two, or three different types. The number of flower types selected by bees on a mixed array consisting of several types was also tested. Interference effects increased with the number and complexity of interfering flower types: a 0% increase for one simple flower type; 278% for two simple flower types; 357% for three simple flower types; and 565% for two complex flower types; switching among more than two flower types caused substantial interference. On the mixed array of three flower types, none of the 20 foragers tested randomly visited all three types, 67% primarily visited two types, and 33% primarily visited one type. These findings suggest that the bees limited the number of flower types to two because of the substantial costs incurred when a third flower type was included in their foraging repertoire.

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Localization of immunolabels by electron microscopy and image averaging

1983 ◽  
Vol 41 ◽  
pp. 282-283
Author(s):  
J. Frank ◽  
P.-Y. Sizaret ◽  
A. Verschoor ◽  
J. Lamy
Keyword(s):  
Electron Microscopy ◽  
Single Particle ◽  
Attachment Site ◽  
Uranyl Acetate ◽  
Limulus Polyphemus ◽  
Resolution Limit ◽  
Electron Microscopic ◽  
Image Averaging ◽  
Top View ◽  
Better Than

The accuracy with which the attachment site of immunolabels bound to macromolecules may be localized in electron microscopic images can be considerably improved by using single particle averaging. The example studied in this work showed that the accuracy may be better than the resolution limit imposed by negative staining (∽2nm).The structure used for this demonstration was a halfmolecule of Limulus polyphemus (LP) hemocyanin, consisting of 24 subunits grouped into four hexamers. The top view of this structure was previously studied by image averaging and correspondence analysis. It was found to vary according to the flip or flop position of the molecule, and to the stain imbalance between diagonally opposed hexamers (“rocking effect”). These findings have recently been incorporated into a model of the full 8 × 6 molecule.LP hemocyanin contains eight different polypeptides, and antibodies specific for one, LP II, were used. Uranyl acetate was used as stain. A total of 58 molecule images (29 unlabelled, 29 labelled with antl-LPII Fab) showing the top view were digitized in the microdensitometer with a sampling distance of 50μ corresponding to 6.25nm.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Electron Microscopic Observation of the Longitudinal Organization of Poly (p-Phenylene Terephthalamide) Fibers

1982 ◽  
Vol 40 ◽  
pp. 680-681
Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Microscopic Observation ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Aromatic Polyamides ◽  
Radial Arrangement ◽  
Scanning Electron ◽  
Better Than

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.

A High Angle, Double Tilting Cold Stage for the AEI EM7

1974 ◽  
Vol 32 ◽  
pp. 450-451
Author(s):  
P.R. Swann ◽  
A.E. Lloyd
Keyword(s):  
Habit Plane ◽  
Temperature Control ◽  
Tilt Angle ◽  
Cooling System ◽  
Thermal Drift ◽  
High Angle ◽  
Cold Stage ◽  
High Degree ◽  
Better Than

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.

Thermal Considerations in Lens Regulator Systems

1970 ◽  
Vol 28 ◽  
pp. 358-359
Author(s):  
K.C. Newton
Keyword(s):  
Electron Microscope ◽  
Thermal Effects ◽  
Environmental Control ◽  
Reference Networks ◽  
Better Than

Thermal effects in lens regulator systems have become a major problem with the extension of electron microscope resolution capabilities below 5 Angstrom units. Larger columns with immersion lenses and increased accelerating potentials have made solutions more difficult by increasing the power being handled. Environmental control, component choice, and wiring design provide answers, however. Figure 1 indicates with broken lines where thermal problems develop in regulator systemsExtensive environmental control is required in the sampling and reference networks. In each case, stability better than I ppm/min. is required. Components with thermal coefficients satisfactory for these applications without environmental control are either not available or priced prohibitively.

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