Hideki Tateda

Moist and dry hygroreceptors for relative humidity of the cockroach,Periplaneta americana L.

SummaryAntennal hygroreceptors of the cockroach,Periplaneta americana L. have been electrophysiologically investigated.1.The moist and dry hygroreceptors, together with a thermal receptor, are contained in a sensillum capitulum, which is located on alternating flagellar segments (Fig. 3).2.The responses of both hygroreceptors are of a phasic-tonic manner, and following the cessation of stimulation, decrease to a level lower than the prestimulation level (Figs. 4, 5).3.The humidity-response relationship of the hygroreceptors is independent of stimulus flux (Fig. 7).4.The responses of the hygroreceptors, when the whole animal and stimulus air are changed simultaneously, are larger at higher than at lower temperatures. The normalized humidity-response relationship of the hygroreceptors at different temperatures are coincident when plotted against relative humidity but not when plotted against absolute humidity (Figs. 8, 10).5.The humidity-response relationships at different temperatures are coincident when plotted against relative humidity, but not when plotted against absolute humidity, provided that only the stimulus temperature is changed (Figs. 9, 11).6.We conclude that the responses of the hygroreceptors depend on the relative humidity and that the mechanism of the primary process of hygroreception is non-chemical.

Spectral sensitivities of jumping spider eyes

SummarySpectral 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.

Antennal hygroreceptors of the honey bee, Apis mellifera L.

SummaryAntennal hygroreceptors of the honey bee, Apis mellifera L., have been investigated electrophysiologically and the sensillum containing these receptors with SEM. Moist and dry hygroreceptors have been identified along with a thermal receptor in a specialized coeloconic sensillum. This sensillum comprises a cuticular, shallow depression (diameter; 4 μ) having a central opening (1.4–1.5 μm) and a mushroom-shaped protrusion (1.4–1.5 μm) from the opening. The head of the protrusion is irregular in shape and is not perforated. This sensillum has been thus far referred to as a “sensillum campaniformium” (Dietz and Humphreys 1971), henceforth, it is referred to as a coelocapitular sensillum.The responses of both moist and dry hygroreceptors are of a phasic-tonic manner. Both receptors are antagonistic with respect to their responses to humidity; one responds with an increase in impulse frequency to rising humidity, the other to falling humidity. The humidity-response relationship is independent of stimulus flux.

Distribution of color receptors in the larval eyes of four species of lepidoptera

Summary1.Caterpillars of the noctuid mothMamestra brassicae have six stemmata (I-VI) on either side of the head. Each stemma has seven photoreceptor cells (Fig. 1). Photoreceptor cells are spectrally differentiated into three types: UV, blue, and green (Fig. 2).2.Stemmata I and III have five green and two blue receptors; stemmata II, V, and VI have four green, one blue, and two UV receptors; stemma IV has five green and two UV receptors (Table 1).3.The spectral sensitivities of all photoreceptor cells inMamestra except for one, R4 of stemma IV, are the same as those of the anatomically equivalent cells inPapilio xuthus (Fig. 3). The R4 of IV in the former is a green receptor, while in the latter it is a blue receptor.4.The fact that the R4s of stemma IV inMamestra andPapilio differ from each other physiologically may be related to the phylogenetic distance between the two species. Support for this point of view comes from the finding that inBombyx mori, thought to be relatively closely related toMamestra, the R4 in stemma IV is a green receptor (Fig. 6) while inPieris rapae crucivora more closely related toPapilio it seems to be a blue receptor (Table 2).

Cellular patterns and spectral sensitivity of larval ocelli in the swallowtail butterflyPapilio

SummaryCaterpillars of the swallowtail butterflyPapilio xuthus L. like most lepidopterans have six larval ocelli (stemmata) on each side of the head (Fig. 1). Five of these (II–VI) are arranged in a close ellipsoidal cluster from which number I is somewhat isolated ventrally (Fig. 2). Each stemma has seven retinular cells (R) organized in two tiers (proximal and distal, Fig. 3) but the cellular patterns and spectral sensitivities fall into three classes. As proved by intracellular recordings (Fig. 4) stemmata I and III have five green receptors (λmax ca. 530 nm) and two blue ones (λmax ca. 450 nm) (Fig. 5). The other ocelli have only four green and one blue cell, but have in addition two UV units each (λmax ca. 370 nm); in II and IV one green cell (R6) is proximally located (Fig. 6), in V and VI it is distal. All distal cells whether three (I–IV) or four (V, VI) in number are green units. Hence all blue and UV receptors are in the proximal cell tier with UV limited to R5 and R7, blue to R4, R5, and R7 (Fig. 7).

Regulation of insect brain excitability by ocellus

SummaryUnitary discharges were recorded from various areas of the brain in the fleshfly (Boettcherisca peregrina), whose compound eyes were occluded to light but the ocelli were exposed to it.1.Giving olfactory and mechanical stimulation to the antenna, the excitatory and the inhibitory neurones were found. In the excitatory neurones the unitary discharges appeared during the stimulation or the spontaneous discharges were increased by it. Phasic responses were found mostly in the protocerebrum, and tonic ones were in the deutocerebra, tritocerebra and the suboesophageal ganglion. In the inhibitory neurones the spontaneous discharges disappeared during the stimulation. The inhibition of the discharge was tonic in the deuto- and tritocerebra.2.When the ocelli were illuminated, the frequency of the spontaneous discharges was increased in many units and was decreased in some units.3.By turning off the illumination to the ocelli, the unitary response to the antennal stimulation was decreased (light facilitatory unit) in most units of the protocerebrum, while it was increased (light occlusive unit) in most units of the deutocerebra, tritocerebra and the suboesophageal ganglion.4.By darkening the ocelli, the latency of the unitary response was prolonged in most of the light facilitatory units, while it was shortened in the light occlusive units.5.The light facilitatory units were mainly found in the medial region of the brain, and the light occlusive units were in the dorsal region of the protocerebrum and in the ventral region of the deutocerebra, tritocerebra and the suboesophageal ganglion. The results suggest that the ocelli regulate the brain activity.

An electrophysiological study of olfactory interneurones in the brain of the honey-bee.

Abstract Discharges of the olfactory units in the brain of the honey-bee were recorded extracellularly. Discharges were excitatory and inhibitory and showed on and on-off responses. In the on responses, phasic, phasic-tonic, and tonic patterns were found. No relation between discharge pattern and the region in the brain was found. The dominant pattern was phasic-tonic in the excitatory and tonic in the inhibitory units. Rebound or long-lasting phenomena seemed to be one of the characteristics of the neurones in the central nervous system. The latency of the response showed that olfactory information entering the deutocerebrum from the antenna was carried to the calyx of the ipsilateral brain via the antenno-cerebral tracts reported by Kenyon (1896), and then to the protocerebral lobe through the stalk of the mushroom body. The information was also carried to the contralateral brain after passing through the calyx of the ipsilateral brain or the central commissure.

The taste response of the isolated barbel of the catfish

Abstract 1. 1. The taste responses from the isolated barbel of the catfish, Parasilurus asotus Linne, were studied electrophysiologically, using single fiber techniques and the electronic summator. 2. 2. The majority of single fibers in the barbels responded to hydrochloric acid and salt, but not to sucrose and quinine. The pattern of relative effectiveness of these substances differed from fiber to fiber and no classification of fiber types was clear. 3. 3. The pattern of effectiveness of monovalent salts, NH4Cl, NaCl and LiCl, also varied from fiber to fiber. 4. 4. Potassium chloride and calcium chloride of 0·25-1·0 M caused irreversible change in the taste responses. Urethane and cocaine also abolished the taste response.

Intracellular stainings of the large ocellar second order neurons in the cockroach

SummaryThe large ocellar second order neurons (L-neurons) in the cockroach,Periplaneta americana have been studied physiologically by intracellular recordings and morphologically by intracellular and whole nerve cobalt stainings. All the recorded L-neurons showed similar light responses, i.e., light on-hyperpolarization and a small number of off-spikes. All the stained L-neurons had an ocellar arborization covering the whole region of the ocellar neuropile and an central arborization in the region posterior to the protocerebral bridge.

Cerebral photosensitive neurons in the orb weaving spiders,Argiope bruennichii andA. amoena

Summary1.The frequency of efferent impulses in the optic nerves of the orb weaving spidersArgiope bruennichii andA. amoena increased by illumination of the brain. Addition of 2 mmol/l Co2+, a synaptic blocking agent, to the saline resulted in the generation of optic nerve impulses following cerebral illumination. Thus, efferent neurons within the brain appear to be sensitive to light. Maximum sensitivity of these neurons occurs at 420–440 nm.2.The frequency of efferent optic nerve impulses decreased during illumination of the eyes. The spectral sensitivity for this inhibition was measured, a large peak occurring at 480–540 nm and a smaller peak at 360 nm.3.The frequency of efferent optic nerve impulses increased transiently following a diminution in light intensity striking the eyes. Simultaneous diminution of light intensity striking both the eyes and the brain, however, increased the number of impulses from the optic nerve, suggesting that the cerebral photosensitive neurons play a role in increasing the response to dimming of light.