scholarly journals Captivating color: evidence for optimal stimulus design in a polymorphic prey lure

2020 ◽  
Author(s):  
Darrell Kemp ◽  
Will Edwards ◽  
Thomas White
Keyword(s):  
Spectral Range ◽  
Natural Variation ◽  
Polymorphic Variation ◽  
Color Patterns ◽  
Color Spectrum ◽  
Per Se ◽  
Chromatic Properties ◽  
Stimulus Design ◽  
Background Contrast ◽  
Prey Attraction

Araneid spiders use abstract color patterns to attract prey. The chromatic properties of these displays vary extensively, both within and across species, and they are frequently polymorphic. Variation is often expressed in terms of signal hue (color per se), but it is unclear precisely how attractiveness scales with this property. We assessed captures among color-manipulated females of the dimorphic jeweled spider Gasteracantha fornicata in their natural webs. The manipulation magnified the natural variation in stimulus hue independently of chroma (saturation) across a range spanning most of the color spectrum. Catch rate varied across treatments in simple accordance with how greatly stimulus hue deviated from either of the two extant phenotypes. Predictions based upon fly-perceived background contrast were unsupported despite dipterans constituting ~60 % of prey. This study isolates the importance of stimulus hue and supports the premise that extant phenotypes reside in an optimal spectral range for prey attraction.

scholarly journals Artificial night light alters nocturnal prey interception outcomes for morphologically variable spiders

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4070 ◽  
Author(s):  
Suet Wai Yuen ◽  
Timothy C. Bonebrake
Keyword(s):  
Morphological Variation ◽  
Species Interactions ◽  
Floral Resources ◽  
Color Contrast ◽  
Color Patterns ◽  
Predator Prey ◽  
Yellow Color ◽  
Set Up ◽  
Prey Attraction

Artificial night light has the potential to significantly alter visually-dependent species interactions. However, examples of disruptions of species interactions through changes in light remain rare and how artificial night light may alter predator–prey relationships are particularly understudied. In this study, we examined whether artificial night light could impact prey attraction and interception inNephila pilipesorb weaver spiders, conspicuous predators who make use of yellow color patterns to mimic floral resources and attract prey to their webs. We measured moth prey attraction and interception responses to treatments where we experimentally manipulated the color/contrast of spider individuals in the field (removed yellow markings) and also set up light manipulations. We found that lit webs had lower rates of moth interception than unlit webs. Spider color, however, had no clear impact on moth interception or attraction rates in lit nor unlit webs. The results show that night light can reduce prey interception for spiders. Additionally, this study highlights how environmental and morphological variation can complicate simple predictions of ecological light pollution’s disruption of species interactions.

Visual edge detection in the honeybee and its chromatic properties

1990 ◽  
Vol 238 (1293) ◽  
pp. 321-330 ◽  
Keyword(s):  
Spatial Distribution ◽  
Edge Detection ◽  
Video Tape ◽  
Entire Surface ◽  
Sugar Water ◽  
Detection Of Objects ◽  
Primate Vision ◽  
Per Se ◽  
Chromatic Properties

Free-flying bees were trained to collect a reward of sugar-water at one of several discs placed horizontally on a contrasting background. In sub­sequent tests the reward was removed and the behaviour of the bees was observed and recorded on video-tape while they landed on the experi­mental arrangement in search of the reward. The spatial distribution of the landings was analysed to measure the detectability of the discs and attractiveness of their boundaries, as com­pared to the interior regions. The results reveal that, while landing on figures, bees pay special attention to the edges. Even though the reward is placed at a randomly chosen location within the figure during training, the bees show a distinct preference for landing near the boundary of the figure. The bees’ preference for edges is restricted to figures with bound­aries that provide contrast to the green-sensitive receptors. When the boundaries contain no green contrast, the edge preference disappears. In this situation, landings continue to occur mainly within the figure, but they tend to be distributed randomly over its entire surface. Thus, whereas colour information can mediate the detection of objects per se , the detection of edges, at least in the context of landing on a figure, is a colour-blind performance that is driven primarily by signals from the bee’s green-sensitive photoreceptors. This finding has interesting parallels in primate vision, where edge detection is also colour-blind. On the basis of these findings, we propose that edges provide cues that play an important role in guiding landing manouevres towards objects of interest, such as flowers.

Functional significance of preserved color patterns of mollusks from the Gosport Sand (Eocene) of Alabama

1988 ◽  
Vol 62 (01) ◽  
pp. 83-87 ◽  
Author(s):  
Patricia H. Kelley ◽  
Charles T. Swann
Keyword(s):  
Functional Morphology ◽  
Functional Significance ◽  
Intraspecific Variability ◽  
Color Pattern ◽  
Color Patterns ◽  
Historical Factors ◽  
Life Mode ◽  
Molluscan Fauna ◽  
Excellent Preservation ◽  
Architectural Constraints

The excellent preservation of the molluscan fauna from the Gosport Sand (Eocene) at Little Stave Creek, Alabama, has made it possible to describe the preserved color patterns of 15 species. In this study the functional significance of these color patterns is tested in the context of the current adaptationist controversy. The pigment of the color pattern is thought to be a result of metabolic waste disposal. Therefore, the presence of the pigment is functional, although the patterns formed by the pigment may or may not have been adaptive. In this investigation the criteria proposed by Seilacher (1972) for testing the functionality of color patterns were applied to the Gosport fauna and the results compared with life mode as interpreted from knowledge of extant relatives and functional morphology. Using Seilacher's criteria of little ontogenetic and intraspecific variability, the color patterns appear to have been functional. However, the functional morphology studies indicate an infaunal life mode which would preclude functional color patterns. Particular color patterns are instead interpreted to be the result of historical factors, such as multiple adaptive peaks or random fixation of alleles, or of architectural constraints including possibly pleiotropy or allometry. The low variability of color patterns, which was noted within species and genera, suggests that color patterns may also serve a useful taxonomic purpose.

Origin of Hepatic Nuclear Inclusion Bodies

1973 ◽  
Vol 31 ◽  
pp. 426-427
Author(s):  
F. G. Zaki ◽  
J. A. Greenlee ◽  
C. H. Keysser
Keyword(s):  
Inclusion Bodies ◽  
Storage Disease ◽  
Glycogen Storage ◽  
Nutritional Deficiencies ◽  
Nuclear Inclusion ◽  
Electron Microscopic ◽  
Human Liver Cells ◽  
Microscopic Studies ◽  
Per Se ◽  
Experimental Liver

Nuclear inclusion bodies seen in human liver cells may appear in light microscopy as deposits of fat or glycogen resulting from various diseases such as diabetes, hepatitis, cholestasis or glycogen storage disease. These deposits have been also encountered in experimental liver injury and in our animals subjected to nutritional deficiencies, drug intoxication and hepatocarcinogens. Sometimes these deposits fail to demonstrate the presence of fat or glycogen and show PAS negative reaction. Such deposits are considered as viral products.Electron microscopic studies of these nuclei revealed that such inclusion bodies were not products of the nucleus per se but were mere segments of endoplasmic reticulum trapped inside invaginating nuclei (Fig. 1-3).

The Eleventh Circuit Holds that Agreements in which Pharmaceutical Companies Pay Generic Companies Not to Compete May be Valid

2004 ◽  
Vol 32 (1) ◽  
pp. 181-184
Author(s):  
Amy Garrigues
Keyword(s):  
Pharmaceutical Companies ◽  
Court Decisions ◽  
Patent Holder ◽  
Trial Court ◽  
Court Of Appeals ◽  
The Us ◽  
Antitrust Laws ◽  
Per Se ◽  
Appeals Court ◽  
Two Sides

On September 15, 2003, the US. Court of Appeals for the Eleventh Circuit held that agreements between pharmaceutical and generic companies not to compete are not per se unlawful if these agreements do not expand the existing exclusionary right of a patent. The Valley DrugCo.v.Geneva Pharmaceuticals decision emphasizes that the nature of a patent gives the patent holder exclusive rights, and if an agreement merely confirms that exclusivity, then it is not per se unlawful. With this holding, the appeals court reversed the decision of the trial court, which held that agreements under which competitors are paid to stay out of the market are per se violations of the antitrust laws. An examination of the Valley Drugtrial and appeals court decisions sheds light on the two sides of an emerging legal debate concerning the validity of pay-not-to-compete agreements, and more broadly, on the appropriate balance between the seemingly competing interests of patent and antitrust laws.

Fusion and Fission Processes in Exocytosis: Possible Roles for Synexin and Osmotic Lysis in the Two Events

1980 ◽  
Vol 38 ◽  
pp. 594-597
Author(s):  
H.B. Pollard ◽  
C.E. Creutz ◽  
C.J. Pazoles ◽  
J.H. Scott
Keyword(s):  
Small Molecules ◽  
Chromaffin Cells ◽  
Adrenal Glands ◽  
General Concept ◽  
Extracellular Calcium ◽  
Large Protein ◽  
Granule Membrane ◽  
Osmotic Lysis ◽  
Per Se ◽  
Chemical Evidence

Exocytosis is a general concept describing secretion of enzymes, hormones and transmitters that are otherwise sequestered in intracellular granules. Chemical evidence for this concept was first gathered from studies on chromaffin cells in perfused adrenal glands, in which it was found that granule contents, including both large protein and small molecules such as adrenaline and ATP, were released together while the granule membrane was retained in the cell. A number of exhaustive reviews of this early work have been published and are summarized in Reference 1. The critical experiments demonstrating the importance of extracellular calcium for exocytosis per se were also first performed in this system (2,3), further indicating the substantial service given by chromaffin cells to those interested in secretory phenomena over the years.

The importance of physical training for preventive care in the elderly

2002 ◽  
Vol 59 (7) ◽  
pp. 323-327
Author(s):  
Baum
Keyword(s):  
Preventive Care ◽  
Körperliche Aktivität ◽  
Physical Training ◽  
Ältere Menschen ◽  
The Elderly ◽  
Per Se

Der mit zunehmendem Alter beobachtbare Verlust an Kraft, Koordination, Ausdauer und Flexibilität ist nur zum Teil als Alterungsprozess per se zu verstehen. Ein wesentlicher Einflussfaktor ist die körperliche Aktivität, d.h. die impliziten oder expliziten Trainingsreize. Denn alle körperlichen Leistungsmerkmale sind noch bis ins höchste Alter unter der Voraussetzung trainierbar, dass die Trainingsintensität und die Reizdichte hinreichend hoch sind. Bei Trainingsangeboten für ältere Menschen kommen der Kraft und der Koordination eine besondere Bedeutung zu, da sie die Basis für eine selbständige Lebensführung darstellen. Um das Krafttraining aus kardio-vaskulärer Sicht möglichst sicher zu gestalten, wurde von uns eine Trainingsform entwickelt und erprobt, bei der es im Gegensatz zu herkömmlichen Methoden zu signifikant geringeren Blutdruckanstiegen kommt.

Hausstaubmilbenallergie

2012 ◽  
Vol 69 (4) ◽  
pp. 249-252 ◽  
Author(s):  
Carrard ◽  
E. Pichler
Keyword(s):  
Per Se

Hausstaubmilben sind kleine Spinnentiere, die weltweit vom gemäßigten bis zum tropischen Klima gefunden werden. Proteine, alle mit enzymatischen Eigenschaften, aus dem Gastrointestinaltrakt und folglich im Hausstaubmilbenkot sind Auslöser von allergischen Erkrankungen, die aufgrund einer kontinuierlichen Exposition von geringen Allergenmengen meist chronisch verlaufen. Klinisch äußert sich dies mit einem schleichenden Krankheitsbeginn: eine chronisch verstopfte Nase und - zu Beginn typischerweise - einem Anstrengungsasthma, das sich bei längerer Dauer verstärkt. Bei Vorliegen einer atopischen Dermatitis kann es auch nach Milbenkontakt zu einer Verstärkung der Dermatitis kommen. Die Anzahl an Hausstaubmilben und die Menge an Milbenallergen hängt von der relativen Luftfeuchtigkeit ab, wobei eine Luftfeuchtigkeit von > 50 %, wie es in sehr gut isolierten Häusern oder durch das Klima per se vorkommt, zu einem guten Gedeihen der Hausstaubmilben führt. Nahrungsquelle der Hausstaubmilben sind Hautschuppen, die ubiquitär in Polstermöbeln, Matratzen und Teppichen vorkommen. Die chronischen, recht unspezifischen und oft allergenunabhängigen Beschwerden verzögern oft die Diagnostik, welche durch eine ausgedehnte Allergieabklärung z. B. mittels Hauttestung erfolgt. Die Therapie besteht in erster Linie aus topischen Kortikosteroiden. Trotz widersprüchlicher Daten und Metaanalysen in der Literatur zur Hausstaubsanierung scheint das allgemein eher trockene Klima im Winter in der Schweiz eine Hausstaubsanierung in den Wohnungen zu begünstigen und wird deshalb auch empfohlen. Eine weitere Therapieoption ist die Durchführung einer spezifischen Immuntherapie mit gutem Erfolg bei Kindern und Erwachsenen. Verbesserungen der Diagnostik und Immuntherapie sind durch Einsatz der rekombinanten Allergene zu erwarten.

Harnsäure, Nierenerkrankungen und Nephrolithiasis

2016 ◽  
Vol 73 (3) ◽  
pp. 159-165 ◽  
Author(s):  
Min Jeong Kim ◽  
Helmut Hopfer ◽  
Michael Mayr
Keyword(s):  
Diabetes Mellitus ◽  
Diabetes Mellitus Typ 2 ◽  
Therapeutische Konsequenzen ◽  
Per Se

Zusammenfassung. Verschiedene Nierenerkrankungen können mit erhöhten Harnsäurewerten einhergehen, wobei die pathophysiologischen Vorgänge sich stark unterscheiden. Dies ist nicht nur von akademischer Bedeutung, sondern hat auch wichtige therapeutische Konsequenzen. Während ein massiver und plötzlicher Harnsäure-Anfall im Rahmen eines Tumor-Lyse-Syndroms zum akuten Nierenversagen führen kann, liegen der umstrittenen chronischen Urat-Nephropathie dauerhaft erhöhte Harnsäurewerte zugrunde. Möglicherweise ist hier das entscheidende Agens aber gar nicht die Hyperurikämie per se, sondern Blei, zumindest gibt es diese Assoziation. Bei der Nephrolithiasis mit Harnsäuresteinen ist der entscheidende Faktor nicht wie zu vermuten wäre eine Hyperurikämie oder Hyperurikosurie, sondern eine Azidifikationsstörung auf renaler Ebene mit persistierend tiefem Urin-pH. Es gibt starke Hinweise, dass die beiden metabolischen Erkrankungen Adipositas und der Diabetes mellitus Typ 2 mit Insulinresistenz wichtige pathophysiologische Faktoren in der Entstehung dieser Azidifikationsstörung sind. Patienten mit Harnsäuresteinen sollten deshalb immer auf das Vorliegen dieser metabolischen Faktoren abgeklärt und dementsprechend behandelt werden.

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