Large Hind Wings Enhance Gliding Performance in Ground Effect in a Neotropical Butterfly (Lepidoptera: Nymphalidae)

2019 ◽  
Vol 113 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Marc Stylman ◽  
Carla M Penz ◽  
Phil DeVries
Keyword(s):  
Potential Role ◽  
Hind Wing ◽  
Beat Frequency ◽  
Ground Effect ◽  
Ground Level ◽  
Laboratory Setting ◽  
Wing Area ◽  
Area Reduction ◽  
Gliding Flight

Abstract Neotropical butterflies in the nymphalid genera Pierella Herrich-Schäffer, 1865 (Lepidoptera, Nymphalidae) and Cithaerias Hübner, 1819 (Lepidoptera, Nymphalidae) are known to glide near ground level, and have a high forewing aspect ratio. The hind wings of Pierella are proportionately larger than those of Cithaerias, suggesting a potential role in gliding flight. We show that Pierella helvina (Hewitson, 1860) (Lepidoptera, Nymphalidae) is capable of gliding for longer periods of time than Cithaerias pireta (Stoll, 1780) (Lepidoptera, Nymphalidae) both in the field and a laboratory setting. Experimental reduction of hind wing area in P. helvina led to a decrease in male gliding performance, and an increase in female wing-beat frequency. We also found that escape velocity decreased in both sexes after hind wing area reduction, but the effect was strongest in females. Although the increased drag associated with large hind wings could be detrimental to gliding flight, the large hind wing area of P. helvina effectively enhances gliding performance in ground effect. This study is the first to investigate the role of hind wings on butterfly gliding performance.

The potential role of the estuarine amphipod Gammarus duebeni in sub-lethal ecotoxicology testing

1996 ◽  
Vol 34 (7-8) ◽  
pp. 93-100 ◽  
Author(s):  
Andrew Lawrence ◽  
Carl Poulter
Keyword(s):  
Respiration Rate ◽  
Potential Role ◽  
Beat Frequency ◽  
Water And Sediment ◽  
Swimming Efficiency ◽  
Significant Impairment ◽  
Estuarine Pollution ◽  
Further Development ◽  
Copper Pollution

The aim of this study was to assess the suitability of Gammarus duebeni as an indicator of estuarine pollution. This involved the development of sub-lethal pollution bioassays monitoring respiration rate, swimming efficiency and precopula pairing; assessment of the sensitivity of the assays to copper pollution and comparison of the suitability of the assays. Significant impairment of respiration rate, as measured by changes in pleopod beat, was determined at a copper concentration of 600 μg 1−1. Significant impairment to swimming ability was determined after exposure to copper pollution at a concentration of 600 μg 1−1 and precopula pairing was significantly reduced at a concentration of 600 μg 1−1. Of the assays, swimming efficiency and pleopod beat frequency appear to offer the most potential for further development. The lower limit of sensitivity of the bioassays developed in this study is yet to be determined. However, the levels of copper shown to induce an effect can be experienced in the natural environment. The study has shown thatGammarus duebeni can be used in sub-lethal pollution assays, at relatively high Cu concentrations, and indicates that it is potentially a useful species with which to assess estuarine water and sediment pollution.

scholarly journals Exploring the role of Visual Salience within the Proximity Effect

2018 ◽  
Author(s):  
Daniel Knowles ◽  
Kyle Brown ◽  
Silvio Aldrovandi
Keyword(s):  
Pilot Study ◽  
Cognitive Load ◽  
Laboratory Study ◽  
Proximity Effect ◽  
Potential Role ◽  
Laboratory Setting ◽  
Visual Salience ◽  
Physical Effort ◽  
Do So

Research into why the proximity effect occurs and understanding of the underpinning mechanisms is relatively scarce. Attempts have been made to explore whether cognitive load and physical effort underpin the effect, but no previous study has experimentally manipulated visual salience to determine its role in the proximity effect. The present study aims to be the first to do so, starting with a pilot study to determine an effective operationalisation of visual salience in a laboratory setting. The selected manipulation will then be used in a laboratory study conducted with 68 individuals in a 2(Distance; 20cm vs 70cm) x 2(Visual Salience; Low vs High) between subjects design. Actual and Likelihood of consumption will be measured and statistically compared between conditions to determine the potential role of Visual Salience within the Proximity Effect.

Role of the Cilia Membrane in Control of Microtubule Sliding

1980 ◽  
Vol 38 ◽  
pp. 612-615
Author(s):  
Edna S. Kaneshiro
Keyword(s):  
Control Mechanism ◽  
Beat Frequency ◽  
Surface Membrane ◽  
Ciliary Membrane ◽  
Ciliary Beating ◽  
Ciliary Reversal ◽  
Voltage Dependent ◽  
Reversal Mechanism ◽  
And Function

It is currently believed that ciliary beating results from microtubule sliding which is restricted in regions to cause bending. Cilia beat can be modified to bring about changes in beat frequency, cessation of beat and reversal in beat direction. In ciliated protozoans these modifications which determine swimming behavior have been shown to be related to intracellular (intraciliary) Ca2+ concentrations. The Ca2+ levels are in turn governed by the surface ciliary membrane which exhibits increased Ca2+ conductance (permeability) in response to depolarization. Mutants with altered behaviors have been isolated. Pawn mutants fail to exhibit reversal of the effective stroke of ciliary beat and therefore cannot swim backward. They lack the increased inward Ca2+ current in response to depolarizing stimuli. Both normal and pawn Paramecium made leaky to Ca2+ by Triton extrac¬tion of the surface membrane exhibit backward swimming only in reactivating solutions containing greater than IO-6 M Ca2+ Thus in pawns the ciliary reversal mechanism itself is left operational and only the control mechanism at the membrane is affected. The topographic location of voltage-dependent Ca2+ channels has been identified as a component of the ciliary mem¬brane since the inward Ca2+ conductance response is eliminated by deciliation and the return of the response occurs during cilia regeneration. Since the ciliary membrane has been impli¬cated in the control of Ca2+ levels in the cilium and therefore is the site of at least one kind of control of microtubule sliding, we have focused our attention on understanding the structure and function of the membrane.

POPDC proteins and cardiac function

2019 ◽  
Vol 47 (5) ◽  
pp. 1393-1404 ◽  
Author(s):  
Thomas Brand
Keyword(s):  
Potential Role ◽  
Striated Muscle ◽  
Short Review ◽  
Effector Proteins ◽  
Muscle Disease ◽  
Disease Genes ◽  
Protein Protein Interaction ◽  
Interaction Partners ◽  
And Function

Abstract The Popeye domain-containing gene family encodes a novel class of cAMP effector proteins in striated muscle tissue. In this short review, we first introduce the protein family and discuss their structure and function with an emphasis on their role in cyclic AMP signalling. Another focus of this review is the recently discovered role of POPDC genes as striated muscle disease genes, which have been associated with cardiac arrhythmia and muscular dystrophy. The pathological phenotypes observed in patients will be compared with phenotypes present in null and knockin mutations in zebrafish and mouse. A number of protein–protein interaction partners have been discovered and the potential role of POPDC proteins to control the subcellular localization and function of these interacting proteins will be discussed. Finally, we outline several areas, where research is urgently needed.

The Effect of Path Length and Display Size on Memory for Spatial Information

2012 ◽  
Vol 59 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay
Keyword(s):  
Path Length ◽  
Potential Role ◽  
Spatial Information ◽  
Recall Performance ◽  
Minor Role ◽  
Length Effect ◽  
Serial Memory ◽  
Fixed Reference ◽  
A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

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