The Control of Eyestalk Movements in the Mysid Shrimp Praunus Flexuosus

1975 ◽  
Vol 62 (2) ◽  
pp. 487-504
Author(s):  
D. M. NEIL
Keyword(s):  
Light Beam ◽  
Visual Cues ◽  
Light Conditions ◽  
Free Swimming ◽  
Light Reaction ◽  
Gravity Receptors ◽  
Light Stimuli ◽  
Necessary And Sufficient ◽  
Tracking Response ◽  
Mysid Shrimp

The compensatory eyestalk movements of intact and statocystless mysid shrimps Praunus flexuosus have been measured under a variety of light conditions. The results indicate that the statocyst organs in the urppods are the major gravity receptors, and that they are both necessary and sufficient to produce sinusoidal compensatory eyestalk movements. The addition of visual cues (vertical light beam, optokinetic stimuli) modifies the eyestalk response to some extent, but does not alter its general form. When the statocysts are removed, however, light stimuli become important orientational cues, and the eyestalks perform a tracking response which is considered to be the experimental counterpart of the dorsal light reaction of the free-swimming animal.

The Mechanism of Statocyst Operation in the Mysid Shrimp Praunus Flexuosus

1975 ◽  
Vol 62 (3) ◽  
pp. 685-700
Author(s):  
D. M. NEIL
Keyword(s):  
Body Tilt ◽  
Structural Constraints ◽  
Decapod Crustaceans ◽  
Before And After ◽  
Adequate Stimulus ◽  
Gravity Receptors ◽  
Mysid Shrimp

Analysis of the compensatory eyestalk responses of mysid shrimps before and after the removal of one statocyst has revealed, in the light of statocyst anatomy, that the two statocysts co-operate in their action at all angles of body tilt. Many features of statocyst operation in mysids are shared by decapod crustaceans, but an important difference exists between the geometries of the two statocyst systems. The consequences of this difference highlight the structural constraints on systems of statolithic gravity receptors for which shear magnitude is the adequate stimulus.

Directional Differences in the Colour Sensitivity of Daphnia Magna

1974 ◽  
Vol 61 (1) ◽  
pp. 261-267
Author(s):  
STEPHEN YOUNG
Keyword(s):  
Eye Movements ◽  
Light Intensity ◽  
Light Beam ◽  
Compound Eye ◽  
Action Spectrum ◽  
Stimulus Light ◽  
Free Swimming ◽  
Action Spectra ◽  
Light Receptor ◽  
Flashing Light

1. The Daphnia compound eye movements can be driven by a flashing light. 2. The action spectrum for the threshold light intensity required to evoke this response depends on the orientation of the stimulus light beam with respect to the animal. 3. If the light falls on the eye through the top of the animal's head the action spectrum peaks at the low wavelength end of the spectrum, while if it falls on the eye through the side of the head the peak is in the yellow-green. 4. Eye movements cannot be evoked by illuminating any part of the animal except the compound eye so neither of these action spectra is due to a light receptor other than the compound eye. 5. Some anomalous action spectra in the literature on the behaviour of free-swimming Daphnia are accounted for.

Shelter preference in the Marmorkrebs (marbled crayfish)

Behaviour ◽  
2016 ◽  
Vol 153 (15) ◽  
pp. 1913-1930 ◽  
Author(s):  
Kazuya Takahashi ◽  
Toshiki Nagayama
Keyword(s):  
Social Interactions ◽  
Visual Cues ◽  
Light Conditions ◽  
Valuable Source ◽  
Tactile Cues ◽  
Dark Conditions ◽  
Marbled Crayfish ◽  
Measured Preference

For many animals, shelters are valuable source to hide from predators. To know acquisition of adequate shelter is important to understand social interactions of animals. Preferences for types of shelter used by the Marmorkrebs (marbled crayfish) were analysed behaviourally. Individual crayfish were presented with a choice between two PVC pipes with four different internal diameters (XL, L, M and S). The time spent in each shelter and the number of times crayfish entered each shelter were measured. Preference ranks of crayfish were XL = L = or > M > S. Our experiments strongly suggested that crayfish chose shelters based first on the diameter of the entrance, and then based on the length of the shelter. Crayfish recognised adequate shelters by visual cues under light conditions and utilised tactile cues from their antennae under dark conditions.

Invasive mosquitofish (Gambusia holbrooki) affect egg-laying and behaviour of Spanish pygmy newts (Triturus pygmaeus)

2019 ◽  
Vol 40 (1) ◽  
pp. 103-112 ◽  
Author(s):  
Elisa Cabrera-Guzmán ◽  
Carmen Díaz-Paniagua ◽  
Ivan Gomez-Mestre
Keyword(s):  
Invasive Species ◽  
Visual Cues ◽  
Reproductive Behaviour ◽  
Amphibian Declines ◽  
Egg Laying ◽  
Physical Contact ◽  
Gambusia Holbrooki ◽  
Free Swimming ◽  
In The Wild ◽  
Eastern Mosquitofish

Abstract Invasive species are one of the main causes of amphibian declines worldwide, often through direct predation. Even species or life stages that may not be prone to predation by invasive animals can be affected through alterations of their reproductive behaviour and/or performance. This aspect is less commonly investigated, and may be important for understanding the full impact of invasive species on local amphibian populations. We used laboratory experiments to measure effects of the invasive Eastern mosquitofish (Gambusia holbrooki) on gravid pygmy newts (Triturus pygmaeus) from southern Spain. Gravid newts altered their position in the water column by moving from the bottom of the aquaria to the surface when in the presence of free-swimming mosquitofish, presumably to reduce physical contact with them. Newts also detected and consumed less prey in presence of free mosquitofish. Newts exposed to caged or free-swimming mosquitofish laid fewer eggs than newts not exposed to the invasive species, suggesting that chemical or visual cues alone were sufficient to alter the behaviour of gravid newts. Our results suggest that mosquitofish can reduce the reproductive success of native pygmy newts in the wild, highlighting the need for management efforts to mitigate this impact.

Optomotor Responses and Nystagmus in Intact, Blinded and Statocystless Cuttlefish (Sepia Officinalis L.)

1970 ◽  
Vol 53 (3) ◽  
pp. 789-796 ◽  
Author(s):  
J. B. MESSENGER
Keyword(s):  
Visual Cues ◽  
Angular Acceleration ◽  
Sepia Officinalis ◽  
Free Swimming ◽  
Bilateral Destruction

1. Evidence is reviewed confirming that the eyes of Sepia move under the influence of gravity, angular acceleration and visual receptors. 2. Visual nystagmus and optomotor responses are described in free-swimming Sepia; these survive bilateral destruction of the statocysts, though they are abolished by blinding. 3. Post-rotatory nystagmus is shown by intact animals in a plain background; in bilaterally blinded animals there are post-rotatory movements of the head. These responses disappear if the statocysts are removed. 4. The post-rotatory nystagmus of intact animals is almost completely suppressed by visual cues. 5. Other effects of blinding and statocyst removal are described.

scholarly journals Gas Exchange Responses of Papaya Leaves to Light Variation as Influenced by Drought

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 881D-881
Author(s):  
Hiphil S. Clemente ◽  
Thomas E. Marler
Keyword(s):  
Gas Exchange ◽  
High Light ◽  
Photon Flux ◽  
Light Conditions ◽  
Low Light ◽  
Daily Water ◽  
The Mean ◽  
To Receive ◽  
Tracking Response ◽  
Mild Drought

Container-grown papaya plants were subjected to a slow drying cycle by replenishing a portion of the mean daily water loss. When light-saturated net CO2 assimilation (A) of stressed plants was ≈70% of well-watered plants, sun–cloud transitions were simulated by placing shadecloth between a lamp and the leaf cuvette. The cuvette was initially positioned to receive photosynthetic photon flux (PPF) of ≈1600 μmol–m–2–s–1. The shadecloth was placed over the cuvette for a 3-min period (250 μmol–m–2–s–1), then removed. Gas-exchange responses were recorded for another 3 min of high light. Within 20 sec of initiating low light on well-watered plants, A was <50% of the high-light value. Stomatal conductance (gs) of these plants began to decline by 60 sec and slowly declined to <90% of the high-light value. Both A and gs recovered to the original values by ≈2 min following return to the high-light conditions. For stressed plants, the decline of gs under low light began earlier and was of greater magnitude, and gs and A recovery following the return to high light was delayed. These results indicate that papaya has suntracking capabilities, and mild drought stress enhances the tracking response.

The extinction time of a general birth and death process with catastrophes

1986 ◽  
Vol 23 (04) ◽  
pp. 851-858 ◽  
Author(s):  
P. J. Brockwell
Keyword(s):  
Laplace Transform ◽  
Size Distribution ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Death Process ◽  
Extinction Time ◽  
Birth And Death Process ◽  
Different Types ◽  
The Laplace Transform ◽  
Necessary And Sufficient

The Laplace transform of the extinction time is determined for a general birth and death process with arbitrary catastrophe rate and catastrophe size distribution. It is assumed only that the birth rates satisfyλ0= 0,λj&gt; 0 for eachj&gt; 0, and. Necessary and sufficient conditions for certain extinction of the population are derived. The results are applied to the linear birth and death process (λj=jλ, µj=jμ) with catastrophes of several different types.

The time course of calcium deposition in shells of the barnacle (Balanus amphititre amphititre) during cyprid-juvenile metamorphosis

1994 ◽  
Vol 52 ◽  
pp. 178-179
Author(s):  
Nancy R. Wallace ◽  
Craig C. Freudenrich ◽  
Karl Wilbur ◽  
Peter Ingram ◽  
Ann LeFurgey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Time Course ◽  
Vertical Plane ◽  
Mantle Cavity ◽  
Qualitative Assessment ◽  
Calcium Deposition ◽  
Free Swimming ◽  
Freeze Dried ◽  
Scanning Electron

The morphology of balanomorph barnacles during metamorphosis from the cyprid larval stage to the juvenile has been examined by light microscopy and scanning electron microscopy (SEM). The free-swimming cyprid attaches to a substrate, rotates 90° in the vertical plane, molts, and assumes the adult shape. The resulting metamorph is clad in soft cuticle and has an adult-like appearance with a mantle cavity, thorax with cirri, and incipient shell plates. At some time during the development from cyprid to juvenile, the barnacle begins to mineralize its shell, but it is not known whether calcification occurs before, during, or after ecdysis. To examine this issue, electron probe x-ray microanalysis (EPXMA) was used to detect calcium in cyprids and juveniles at various times during metamorphosis.Laboratory-raised, free-swimming cyprid larvae were allowed to settle on plastic coverslips in culture dishes of seawater. The cyprids were observed with a dissecting microscope, cryopreserved in liquid nitrogen-cooled liquid propane at various times (0-24 h) during metamorphosis, freeze dried, rotary carbon-coated, and examined with scanning electron microscopy (SEM). EPXMA dot maps were obtained in parallel for qualitative assessment of calcium and other elements in the carapace, wall, and opercular plates.

Supporting the Use of Rudimentary Vocalizations

2014 ◽  
Vol 23 (3) ◽  
pp. 132-139 ◽  
Author(s):  
Lauren Zubow ◽  
Richard Hurtig
Keyword(s):  
Rett Syndrome ◽  
Visual Cues ◽  
Acoustic Analysis ◽  
Eye Gaze ◽  
Research Question ◽  
Primary Research ◽  
Multiple Modalities ◽  
Face To Face ◽  
Perceptual Judgments ◽  
The Face

Children with Rett Syndrome (RS) are reported to use multiple modalities to communicate although their intentionality is often questioned (Bartolotta, Zipp, Simpkins, & Glazewski, 2011; Hetzroni & Rubin, 2006; Sigafoos et al., 2000; Sigafoos, Woodyatt, Tuckeer, Roberts-Pennell, & Pittendreigh, 2000). This paper will present results of a study analyzing the unconventional vocalizations of a child with RS. The primary research question addresses the ability of familiar and unfamiliar listeners to interpret unconventional vocalizations as “yes” or “no” responses. This paper will also address the acoustic analysis and perceptual judgments of these vocalizations. Pre-recorded isolated vocalizations of “yes” and “no” were presented to 5 listeners (mother, father, 1 unfamiliar, and 2 familiar clinicians) and the listeners were asked to rate the vocalizations as either “yes” or “no.” The ratings were compared to the original identification made by the child's mother during the face-to-face interaction from which the samples were drawn. Findings of this study suggest, in this case, the child's vocalizations were intentional and could be interpreted by familiar and unfamiliar listeners as either “yes” or “no” without contextual or visual cues. The results suggest that communication partners should be trained to attend to eye-gaze and vocalizations to ensure the child's intended choice is accurately understood.

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