Spectral sensitivities of jumping spider eyes

Summary Spectral sensitivities of the anterior lateral, posterior lateral and anterior median eyes of the jumping spider,Menemerus confusus Boes. et Str. have been studied by recording electroretinograms (ERGs) and receptor potentials. The anterior and posterior lateral eyes have a single type of visual cell with a maximum spectral sensitivity at about 535–540 nm. The anterior median eye has four types of visual cells with maximum sensitivities at about 360, 480–500, 520–540 and 580 nm, respectively. The ERGs recorded from the optic nerve side (posterior part of the retina) were affected greatly by long wave chromatic light and those on the corneal side (anterior part of the retina) by short wave chromatic light, suggesting that each receptor layer contains a different photopigment.     

Visual pigments and spectral sensitivity of the diurnal gecko Gonatodes albogularis

The visual pigments and oil droplets in the retina of the diurnal gecko Gonatodes albogularis were examined microspectrophotometrically, and the spectral sensitivity under various adapting conditions was recorded using electrophysiological responses. Three classes of visual pigments were identified, with _max at about 542, 475, and 362 nm. Spectral sensitivity functions revealed a broad range of sensitivity, with a peak at approximately 530–540 nm. The cornea and oil droplets were found to be transparent across a range from 350–700 nm, but the lens absorbed short wavelength light below 450 nm. Despite the filtering effect of the lens, a secondary peak in spectral sensitivity to ultraviolet wavelengths was found. These results suggest that G. albogularis does possess the visual mechanisms for discrimination of the color pattern of conspecifics based on either hue or brightness. These findings are discussed in terms of the variation in coloration and social behavior of Gonatodes.Abbreviations ERG electroretinogram - MSP microspectrophotometry - UV ultraviolet - _max wavelength of maximum absorbance     

Identificaton of UV,green and red receptors,and their projection to lamina in the cabbage butterfly,Pieris rapae

Summary The photoreceptors in the compound eye of a cabbage butterfly, Pieris rapae, were examined by conventional and intracellular-labeling electron microscopy by the use of the cobalt(III)-lysine complex as an ionized marker. Five types of spectral sensitivity were recorded intracellularly in electrophysiological experiments. They peaked at about 340, 380, 480, 560 and 620 nm, respectively. One of the distal retinula cells (R2) was a UV receptor, whereas the R4 distal retinula cell was a green receptor. The basal retinula cell, R9, was found to be a red receptor; it was localized near the basement membrane, having a bilobed cell body with an individual nucleus in each lobe. A small number of rhabdomere microvilli were present in a narrow cytoplasmic bridge connecting the two lobes. The axons of six retinula cells (R3–R8) in each ommatidium terminated at the cartridge in the lamina (short visual fiber), whereas those of the other three retinula cells, R1, R2 and R9, extended to the medulla (long visual fiber). The information from the UV and red receptors is therefore probably delivered directly to the medulla neurons, independent of that from the other spectral receptor types.     

Intraspecific variation of spectral sensitivity in threespine stickleback (Gasterosteus aculeatus) from different photic regimes

To examine the influence of the spectral characteristics of underwater light on spectral sensitivity of the ON and OFF visual pathways, compound action potential recordings were made from retinal ganglion cells of threespine stickleback from different photic regimes. In fish from a red-shifted photic regime (P₅₀ 680 nm for downwelling light at 1m), peak sensitivity of both the ON and OFF pathways was limited to long wavelength light (_max 600–620). In contrast, the ON pathway of fish from a comparatively blue-shifted (P₅₀ 566 nm) photic regime exhibited sensitivity to medium (_max 540–560) and long (_max 600 nm) wavelengths, while the OFF pathway exhibited peak sensitivity to only medium (_max 540 nm) wavelength light. In a third population, where the the ambient light is moderately red-shifted (P₅₀ 629 nm), the ON pathway once again exhibited only a long wavelength sensitivity peak at 620 nm, while the OFF pathway exhibited sensitivity to both medium (_max 560 nm) and long (_max 600–620 nm) wavelength light. These findings suggest that the photic environment plays an integral role in shaping spectral sensitivity of the ON and OFF pathways.     

Determination of first order rate constants by natural logarithm of the slope plot exemplified by analysis of Aspergillus niger in batch culture

Finding rate constants from experimental data is often difficult because of offset and noise. A computer program was developed to average experimental data points, reducing the effect of noise, and to produce a log_e of slope plot – a plot of the natural logarithm of the slope of a curve – eliminating the effect of any offset. If y-values depend exponentially on x-values the log_e of slope plot is rectilinear and the slope is equal to the first order rate constant. Therefore the log_e of slope plot provides easy identification of exponential sections of any experimental or calculated data, corresponding rate constants, and small changes in the rate constant as exemplified by analysis of titrant added to a batch culture of Aspergillus niger. The log_e of slope plot was easily applicable and superior to conventional methods of analysis of exponential decreasing or increasing data.     

Spectral Sensitivity of the Common Prawn, Palaemonetes vulgaris

The vision of Palaemonetes is of particular interest in view of extensive studies of the responses of its chromatophore systems and eye pigments to light. The spectral sensitivity is here examined under conditions of dark adaptation and adaptation to bright colored lights. In each case the relative number of photons per one-fiftieth sec flash needed to evoke a constant peak amplitude (usually 25 or 50 µv) in the electroretinogram (ERG) was measured at various wavelengths throughout the spectrum. The sensitivity is the reciprocal of this number. In dark-adapted animals the spectral sensitivity curve consists of a broad, almost symmetrical band, maximal at about 540 mµ, with a shoulder near 390 mµ. Adaptation to bright red or blue light, left on continuously throughout the measurements, depresses the 540 mµ peak without notably changing its shape or position, implying that only one visual pigment operates in this region. Adaptation to red light, however, spares a violet-sensitive system, so that a high, narrow peak at 390 mµ now dominates the spectral sensitivity function. The 540 and 390 mµ peaks are apparently associated with different visual pigments; and these seem to be segregated in different receptor systems, since the associated ERG's have markedly different time constants. It is suggested that these two sensitivity bands may represent the red- and violet-sensitive components of an apparatus for color differentiation.     

Electrophysiological evidence for interaction between retinula cells in the flesh-fly

Summary In the electrical response of retinula cells to polarized light in the flesh-flyBoettcherisca peregrina, the polarization plane which showed the maximum sensitivity (Pol_max phase) to illumination by a small spot of light just large enough to cover only one retinula cell was found to differ from that with illumination by a larger spot of light which included adjacent cells. There was a difference of about 30°.This difference in Pol_max phase was assumed to indicate the occurrence of interaction between retinula cells even in the fly photoreceptor having rhabdom of the open type. This assumption was confirmed by the following experiments. (1) Under selective adaptation by a large spot of polarized light so as to eliminate the interaction effect, the Pol_max phase was found to be the same as that measured by a small spot even though the measurement had been made using a large spot of light. (2) The responses to polarized light illuminated from along some restricted off-axes showed a 60° shift in the Pol_max phase in comparison to those obtained from along the other axes. (3) The spectral sensitivity curves to illumination from along off-axes were almost all the same and were for the peripheral retinula cells. (4) The receptor potentials were found to increase in amplitude in a certain limited off-axis area that corresponded to the specific off-axis direction of illumination which had resulted in a shift of the Pol_max phase.It is concluded from these results that the peripheral retinula cells in the flesh-fly demonstrate interaction between certain two adjacent retinula cells. This interaction is positive but not a simple algebraic sum of the activity of two cells.This work was partly supported by a grant from the Japan Education MinistryI wish to thank the Department of Biology, Faculty of Sciences, Kyushu University (Prof. H. Morita and Prof. H. Tateda) for the constant supply of flesh-flies.     

Effects of excitatory amino acid antagonists on synaptic transmission in the ampullae of Lorenzini of the skate Raja clavata

Summary The spectral sensitivity of the ocellus in the cucumber looper moth, Anadevidia peponis, was investigated by recording electroretinograms (ERGs). The peak sensitivities were observed at 340 nm in the ultraviolet and at 520–540 nm in the green. Selective spectral adaptation revealed the existence of at least two receptor types in the ocellar retina. The ratio of green to ultraviolet sensitivities for an ocellus whose ocellar nerve was cut was higher than that for an intact ocellus. It is suggested that efferent signals which control the spectral sensitivity of the ocellus are present in the ocellar nerve.Abbreviations ERG electroretinogram - GR/UV green to ultraviolet sensitivities - ON ocellar nerve     

The Spectral Sensitivities of Single Cells in the Median Ocellus of Limulus

The spectral sensitivities of single Limulus median ocellus photoreceptors have been determined from records of receptor potentials obtained using intracellular microelectrodes. One class of receptors, called UV cells (ultraviolet cells), depolarizes to near-UV light and is maximally sensitive at 360 nm; a Dartnall template fits the spectral sensitivity curve. A second class of receptors, called visible cells, depolarizes to visible light; the spectral sensitivity curve is fit by a Dartnall template with λ_max at 530 nm. Dark-adapted UV cells are about 2 log units more sensitive than dark-adapted visible cells. UV cells respond with a small hyperpolarization to visible light and the spectral sensitivity curve for this hyperpolarization peaks at 525–550 nm. Visible cells respond with a small hyperpolarization to UV light, and the spectral sensitivity curve for this response peaks at 350–375 nm. Rarely, a double-peaked (360 and 530 nm) spectral sensitivity curve is obtained; two photopigments are involved, as revealed by chromatic adaptation experiments. Thus there may be a small third class of receptor cells containing two photopigments.     

Responses of retinal rods of the frog to light

To study the effect of the intensity, duration, spectral composition, and diameter of the light spot on the amplitude and shape of the response of single rods of the frog retina, potentials were recorded intracellularly. The rods tested could be divided into two groups on the basis of their responses to light spots of different spectral composition: those with maxima of sensitivity at 507 ± 8 nm and 442 ± 8 nm. With an increase in the intensity of light the response amplitude rose gradually and the time for the response to rise to its maximum was shortened. A bright flash temporarily inhibited the sensitivity of the cell to subsequent test flashes. If light spots of larger diameter (1000–1500 µ) were presented a delayed depolarization wave, due to illumination of the distant surroundings of the receptor, was observed in the course of recovery of the photic response; this effect was maximal for stimulation with red light and it was evidently induced by horizontal cell activity. The possible functional role of the depolarizing effect of illumination of the distant surroundings of the receptor is discussed.M. V. Lomonosov Moscow State University. Translated from Neirofiziologiya, Vol. 7, No. 1, pp. 84–92, January–February, 1975.     

Visual spectral sensitivity of hatchling loggerhead (Caretta caretta L.) and leatherback (Dermochelys coriacea L.) sea turtles,as determined by single-flash electroretinography

Electroretinographic recordings were made from hatchling loggerhead and leatherback sea turtle eyecup preparations to generate dark-adapted spectral sensitivity curves. Both species were maximally sensitive to wavelengths between 500 and 540 nm, with a secondary peak near 380 nm. The spectral sensitivity curve for leatherbacks was attenuated at the long wavelength end of the spectrum relative to that of the loggerheads. This difference may reflect adaptations to lighting available at the relatively shallow (loggerhead) versus deeper (leatherback) sites where each species forages. The broad spectrum of wavelengths detected by both species (near UV to yellow–orange) indicates that vision is likely mediated by more than one photopigment, potentially rendering these turtles capable of color vision.     

Action Spectra and Adaptation Properties of Carp Photoreceptors

The mass photoreceptor response of the isolated carp retina was studied after immersing the tissue in aspartate-Ringer solution. Two electro-retinogram components were isolated by differential depth recording: a fast cornea-negative wave, arising in the receptor layer, and a slow, cornea-negative wave arising at some level proximal to the photoreceptors. Only the fast component was investigated further. In complete dark adaptation, its action spectrum peaked near 540 nm and indicated input from both porphyropsin-containing rods (λ_max ≈ 525 nm) and cones with longer wavelength sensitivity. Under photopic conditions a broad action spectrum, λ_max ≈ 580 nm was seen. In the presence of chromatic backgrounds, the photopic curve could be fractionated into three components whose action spectra agreed reasonably well with the spectral characteristics of blue, green, and red cone pigments of the goldfish. In parallel studies, the carp rod pigment was studied in situ by transmission densitometry. The reduction in optical density after a full bleach averaged 0.28 at its λ_max 525 nm. In the isolated retina no regeneration of rod pigment occurred within 2 h after bleaching. The bleaching power of background fields used in adaptation experiments was determined directly. Both rods and cones generated increment threshold functions with slopes of +1 on log-log coordinates over a 3–4 log range of background intensities. Background fields which bleached less than 0.5% rod pigment nevertheless diminished photoreceptor sensitivity. The degree and rate of recovery of receptor sensitivity after exposure to a background field was a function of the total flux (I x t) of the field. Rod saturation, i.e. the abolition of rod voltages, occurred after ≈12% of rod pigment was bleached. In light-adapted retinas bathed in normal Ringer solution, a small test flash elicited a larger response in the presence of an annular background field than when it fell upon a dark retina. The enhancement was not observed in aspartate-treated retinas.     

Unconventional ultraviolet sensitivity spectra of Ascalaphus (Insecta,Neuroptera)

The spectral sensitivity of 21 eye preparations of Ascalaphus (Libelluloides) macaronius (Insecta, Neuroptera) has been re-measured using an up-to-date spectral scan method. 1. Dorso-frontal and ventro-lateral eyes have different spectral characteristics with peaks of sensitivity at 329 ± 8 nm (n = 15) and 343 ± 4 nm (n = 5) (P = 0.002), respectively. 2. The absorbance of the visual pigment layer, K, determined from the shape of the spectral sensitivity curves is 1.3 ± 1.8(n = 15) for dorso-frontal eyes and – 1.0 ± 0.3(n = 5) for ventrolateral eyes, thus implying higher selfscreening in the dorso-frontal eyes and narrowing of the spectral sensitivity curves as regards to a template visual pigment in ventro-lateral eyes. 3. Plotting K versus spectral sensitivity peak wavelength _max revealed an inverse correlation between these variables with K = 42.5 – 0.126 _max at r = 0.88(n = 19). 4. Extracts of ommochromes and carotenoids (Figs. 4 to 6) do not allow to account for the above diversity of optical properties of the Ascalaphus eye (Fig. 7).Abbreviations SSC spectral sensitivity curve - DF dorso-frontal eye - UV ultraviolet - VL ventro-lateral eye     

Visual pigments, oil droplets, ocular media and cone photoreceptor distribution in two species of passerine bird: the blue tit (Parus caeruleus L.) and the blackbird (Turdus merula L.)

The spectral absorption characteristics of the retinal photoreceptors of the blue tit (Parus caeruleus) and blackbird (Turdus merula) were investigated using microspectrophotometry. The retinae of both species contained rods, double cones and four spectrally distinct types of single cone. Whilst the visual pigments and cone oil droplets in the other receptor types are very similar in both species, the wavelength of maximum sensitivity (λ_max) of long-wavelength-sensitive single and double cone visual pigment occurs at a shorter wavelength (557 nm) in the blackbird than in the blue tit (563 nm). Oil droplets located in the long-wavelength-sensitivesingle cones of both species cut off wavelengths below 570–573 nm, theoretically shifting cone peak spectral sensitivity some 40 nm towards the long-wavelength end of the spectrum. This raises the possibility that the precise λ_max of the long-wavelength-sensitive visual pigment is optimised for the visual function of the double cones. The distribution of cone photoreceptors across the retina, determined using conventional light and fluorescence microscopy, also varies between the two species and may reflect differences in their visual ecology. Accepted: 8 January 2000     

Spectral sensitivities of retinular cells measured in intact,living flies by an optical method

Summary The spectral sensitivity of the peripheral retinular cells R1–6 in nine species of intact flies was determined using non-invasive, optical measurements of the increase in reflectance that accompanies the pupillary response. Our technique is to chronically illuminate a localized region of the eye with a long wavelength beam, adjusted to bring pupillary scattering above threshold, then, after stabilization, to stimulate with monochromatic flashes. A criterion increase in scattering is achieved at each wavelength by adjusting flash intensity. Univariance of the pupillary response is demonstrated by Fig. 3.Action spectra measured with this optical method are essentially the same as the published spectral sensitivity functions measured with intracellular electrophysiological methods (Fig. 4 forCalliphora, Fig. 5 forDrosophila, Fig. 7 forEristalis, and Fig. 8 forMusca). This holds for both the long wavelength peak and the high sensitivity in the UV as was consistently found in all investigated fly species.Spectral sensitivity functions for R1–6 of hover flies (family Syrphidae) are quite different in different regions of the same eye. There can also be substantial differences between the two sexes of the same species. The ventral pole of the eye of femaleAllograpta (Fig. 10) contains receptors with a major peak at 450 nm, similar to those ofEristalis. However, the dorsal pole of the same eye contains receptors with a major peak at 495 nm, similar to those ofCalliphom. Both dorsal and ventral regions of the maleToxomerus eye, and the ventral region of the female eye, contain only the 450 nm type of R1-6 (see Fig. 12). However, the dorsal region of the female eye also contains another spectral type of receptor that is maximally sensitive at long wavelength. Eyes of both sexes ofAllograpta (Figs. 10 and 11) contain a mixture of spectral types of receptors R1-6.We thank Dr. Chris Maier of the Connecticut Agricultural Experiment Station, for determination of the Syrphidae. This work was supported by grants EY01140 and EY00785 from the National Eye Institute, U.S.P.H.S., (to GDB), by the Connecticut Lions Eye Research Foundation (to GDB), and by the Netherlands Organization for the Advancement of Pure Research (Z.W.O.), (to DGS).     

Spectral Sensitivity of Larval Mosquito Ocelli

The spectral sensitivity of lateral ocelli in both wild-type and white-eyed larvae of the yellow fever mosquito Aedes aegypti L. (reared in darkness) was measured by means of the electroretinogram. The spectral sensitivity is maximal at about 520 nm, with a small secondary peak near 370 nm. When allowance is made for some screening and filtering by the eye tissues, the spectral sensitivity is in reasonable agreement with the absorption spectrum of ocellar rhodopsin (λ_max = 515 nm).     

Spectral sensitivity of the African cichlid fish,Haplochromis burtoni

Summary Spectral sensitivity of the cichlid fishHaplochromis burtoni was measured under both scotopic and photopic conditions using a two-choice, food reward, operant conditioning paradigm. The highest absolute sensitivity (scotopic) is one quantum for every 5 to 50 rods measured at 475 nm (equivalent to a corneal irradiance of 3.8×10⁶ Q s^–1 cm^–2). A P500₁ photopigment apparently mediates spectral sensitivity over most of the visible spectrum; microspectrophotometric studies of rods had previously shown them to contain this photopigment. However, the scotopic behavioral action spectrum shows a sensitivity to short wavelength light higher than is consistent with a P500₁ photopigment alone mediating the scotopic visual process. Determinations made under photopic conditions reveal a behavioral action spectrum broader than that found under scotopic conditions and consistent with mediation by interaction of the three known cone types in an opponent processing manner. The calculated photopic threshold value of approximately 10⁴ Q s^–1 (receptor)^–1 is in agreement with results from other species and corresponds to a corneal irradiance of about 7×10¹⁰Q s^–1cm^–2.     

Spectral sensitivity of visual cells of the compound eye ofBlatta orientalis

Responses of single visual cells of the anterior part of the compound eye of the oriental cockroachBlatta orientalis were recorded intracellularly. Two spectral types of cells were discovered: ultraviolet receptors with _max 361 nm and green-sensitive receptors with _max 503 nm. The spectral curve of the whole eye, measured by the electroretinogram, included two peaks (=350–370 and 500 nm) and a minimum between 400 and 430 nm. This last fact is interpreted as additional evidence of the dichromatic vision of the cockroach.M. V. Lomonosov Moscow State University. Translated from Neirofiziologiya, Vol. 17, No. 1, pp. 57–61, January–February, 1985.     

Spectral sensitivities of photoreceptors and lamina monopolar cells in the dragonfly,Hemicordulia tau

Summary Five spectral types of photoreceptors with peak sensitivities at 330 nm, 410 nm, 460 nm, 525 nm and 630 nm were recorded from the ventral eye of the dragonfly, Hemicordulia tau. Often the 525 nm photoreceptors presented broader, and the 630 nm photoreceptors narrower, spectral sensitivities than would be excepted of a photopigment with the same peak sensitivity. Four types of lamina monopolar cells (cell types 1–4) were recognised from their dark-adapted spectral sensitivities and their anatomy. The anatomical identification allows tentative assignation to the monopolar cell classification from Sympetrum rubicundulum obtained using Golgi staining (Meinertzhagen and Armett-Kibel 1982). When dark-adapted, the monopolar cells had peak spectral sensitivities that were similar to single photoreceptors or appeared to pool receptor outputs, but in some cases spectral sensitivity changed markedly upon adaptation to white and to chromatic light, in one case (cell type 2) apparently switching off a UV-sensitive input.     

Spectral Sensitivity of the Barnacle, Balanus amphitrite

The extracellular ocellar potential was used to evaluate the spectral sensitivity of the ocellus of the barnacle, Balanus amphitrite. Maximum relative sensitivity was at 530–540 nm. Studies with chromatic adapting lights suggest that the receptors contain a single photopigment. The spectra were relatively broader in the dark as compared to the light-adapted state. This effect was shown to be due to an increase in the slope of the amplitude-intensity function, caused by light adaptation. Studies of tapetal fluorescence and corneal transmission indicate little effect of the ocellar media on the determination of sensitivity.