The morphology and physiology of CAP organs in Jasus novaehollandiae (crustacea,decapoda, reptantia,macrura)

The location and external anatomy of the CAP organs of Jasus novaehollandiae were examined and found to be similar to those in Homarus gammarus (Laverack, 1978a). Histological examination of the organs showed threads or filaments arising from the internal surface of the spines to run through canals in the cuticle and join with dendrites of CAP sensory cells in the region of the hypodermis. The CAP neuron cell bodies lie in the nearby chordotonal organ strand. It is demonstrated that flexion of the limb causes the articulating membrane to deflect the spines of the sensillae distally. A variety of experimental techniques used to investigate the physiology of the organs reveals why previously reported attempts to record from the receptors failed. Direct stimulation of the sensillae with an analogue of the membrane and summation of many traces revealed phase constant responses at points corresponding to the covering and uncovering of the sensillae.     

Polygenic analysis of pattern formation in Drosophila: Specification of campaniform sensilla positions on the wing

This study was designed to measure the degree of correlation between vein formation and the specification of campaniform sensillae positions in the wing of Drosophila melanogaster. The campaniform sensillae are sensory organs placed at various locations on the wing. Those on the third longitudinal vein (L3) were the focus of this analysis. The system of polygenic modifiers of vein length is comparatively simple, as shown in whole chromosome assays of selected lines. This variability provides a sensitive method of altering vein-forming ability and of assessing correlated changes in other parts of the vein pattern. In selection lines of veinlet, sensillae were displaced toward the base of the wing as vein length decreased by distal loss of vein material. Changes in the amount of vein were, however, not directly proportional to changes in sensillae positions. The more distal sensillae were shifted the largest amount. In the mutant tilt, in which reduced L3 vein-forming competence results in subterminal gaps, distal campaniform sensillae were almost completely eliminated. The remaining sensillae were shifted toward the base of the wing where vein formation is normal. The placement of sensillae therefore appears to be sensitive to the same underlying determinants involved in vein-forming competence.     

External morphology of antennae and their sense organs in the roach Gromphadorhina brunneri (Blattoidea: Dictyoptera)

The antennae and their sense organs in nymphs and adult roaches of Gromphadorhina brunneri, were investigated and described. The number of segments and sensillae of the nymphal antennae depend on the developmental stage. Sexual dimorphism is pronounced. Males have longer antennae than females as well as an abundance of especially long sensory hairs (long wavy hairs), which are probably responsible for the perception of female sex pheromones. They also have more thin-walled sensory hairs, for instance, sensilla trichodea. On a morphological basis the sensillae of Gromphadorhina brunneri, were named and classified. Long wavy hairs and large sensory hairs appear to be present also in a related species, G. portentosa, but are lacking in others. Their distribution on the antennae varies greatly from that in G. portentosa but their structure varies only slightly. These two types of sense organs are considered to be specialized forms of sensilla chaetica. They are contact chemoreceptors, as are two other types of sensilla chaetica. Furthermore, thin-walled chemoreceptors are present, such as sensilla trichodea, sensilla basiconica, sensilla coeloconica and a typical mechanoreceptor, the sensillum campaniformium.     

The distribution and organization of CAP sensillae in decapod crustacea

The organization of peg‐like sensillae composing CAP organs is described for a number of representative decapod crustacea. In Natantian forms the sensillae are aligned in linear fashion on the distal side of the appropriate joints. One example, Pasiphaea, possesses a cluster of hair sensillae instead of pegs, possibly indicating the primitive origin of this organ system. In the Reptantia the Macrura have well‐developed groups of sensillae, arranged in broad fan‐shaped arrangements; the Anomura display rather varied plans of small sensillae, and in Porcellana only one group on maxilliped 3 are found. The Brachyura have no CAP organs. The significance of these findings, and their possible implication in the evolution of internal proprioceptors in the crustacea, is discussed.     

The labrum of Schedorhinotermes minor soldier (Isoptera,Rhinotermitidae)

The labrum of Schedorhiontermes minor soldier was examined to determine the distribution, types and structures of sense organs present with both light microscopy and scanning and transmission electron microscopy. Three types of sensilla were recognized: companiform sensillae and two types of sensillae trichodea, the short bristles and the long bristles. The companiform sensillae are singly-innervated receptors distributed in large numbers on the anterolateral margins of the labrum. The short and long bristles are multi-innervated; the former are found all over the surface, the latter are much more scarce and are found only at the front of the labrum. Both are at the same time chemo- and mechanoreceptors. The labrum is strewn with many glandular pits and exhibits at its apex a brush of cuticular not innervated spines. On the basis of ultrastructural evidence and of what we know of the defense mechanisms of the soldier, a functional interpretation is attempted.     

How granivorous Coreus marginatus (Heteroptera: Coreidae) recognises its food

Phytophagous insects select their host plant using multiple sensory modalities including vision, olfaction, gustation and mechanoreception. In the laboratory, we investigated the role of vision, olfaction and gustatory sense in the perception of cues released by seeds of different plant species in granivorous Coreus marginatus (Heteroptera: Coreidae). Juvenile insects were put in a choice arena and offered with different seeds on which they feed naturally (Polygonum, Rumex) and seeds which are not their natural food (Stellaria). Individual bugs were manipulated in one of three ways: 1. blackened compound eyes, 2. coated sensillae on antennae, 3. coated tip of labial pouch. Control individuals were not manipulated. The behaviour of each bug was observed for 12 h. Control bugs fed for a significantly longer time than manipulated ones. Individuals with any senses impaired fed on Stellaria, whereas, the control individuals ignored it. The results suggested that seed selection requires information from all three sensory organs: compound eyes, antennae and sensillae on labial pouch. Further research is required to unravel the importance of each sense for the seed selection.     

Sensory system of 2 species of cercariae of the genus Cryptocotyle (Trematoda, Heterophyidae)

The sensory system of two species of cercariae of the genus Cryptocotyle, C. concavum and C. lingua, is described and differences are indicated in the location of sensillae of both species which make possible the clear differentiation of both species.     

Structure and localization of sensilla on antennae of caddisflies (Insecta: Trichoptera)

Structure of antenna segments and ultrastructure of antennal sensillae in representatives of 28 caddisfly families from both modern suborders were studied by electron and light microscopy methods. On Trichoptera antennae, 16 types of sensillae were found, some of them being described for the first time. Morphological peculiarities of cuticular ultrastructures on the antennal surface demonstrate essential differences in structure both at the family level and at the lower taxonomic levels. Specialized sensory fields structurally different from the remaining antennal surface were revealed on antennal flagellae in representatives of the Phryganeina suborder. A new classification of sensillae based on the structure of their cuticular section is proposed.     

Three-dimensional fine structural reconstruction of the nose sensory structures of Acrobeles complexus compared to Caenorhabditis elegans (Nematoda: Rhabditida)

Nematode sensory structures can be divided into two classes; cuticular sensillae, with dendrites ending outside the epidermis, and internal receptors, that typically are single dendrites terminating within the body cavity. Fine structure of the former has been described completely in more than a dozen nematode taxa, while the latter were previously only well understood in the microbial feeder Caenorhabditis elegans. The distantly related nematode Acrobeles complexus has a similar ecology and together the two span a clade representing a large proportion of nematode biodiversity. The cuticular sensillae and internal receptors of A. complexus are here shown to be remarkably similar in number, arrangement, and morphology to those of C. elegans. Several key differences are reported that likely relate to function, and suggest that this nematode has a cuticular sensillum morphology that is closer to that of the common ancestor of the two taxa. Internal sensory receptors have more elaborate termini than those of C. elegans. The existence of a novel form of mechanoreceptor in A. complexus and spatial relationships between sensillum dendrites suggest differences between two classes of sensillae in how a touch-response behavior may be mediated.     

Wing receptors of the American cockroach Periplaneta americana]

Wing receptors of the cockroach have been studied using staining technique with methylene blue in living animals. Five types of the receptors were found: trychoid hairs, bristles, complaniform sensillae, chordotonal organs and multiterminal neurons. The majority of the receptors is located at the lower surface of the wing, especially along its ribs. Together with primitive features in the structure (polyneuronal origin of hairs and bristles, poor content of chordotonal organs, absence of distinct groups of companiform sensillae), some specialization of wing receptors with respect to flight function is noted (concentration of proprioceptors along the main mechanical axis of the wing and formation of distinct rows by the companiform sensillae).     

The effect of ouabain on the sugar receptor of the contact chemoreceptive sensilla of the fly Protophormia terraenovae]

Studies have been made on the inhibitory effect of ouabain solutions on bioelectrical activity of the labellar sensillae of flied. It was shown that 10(-2) M ouabain solution irreversibly inhibits the activity, where as 10(-3) and 10(-4) M concentrations decrease the frequency of impulses within 40-60 min. Ouabain solution is a specific stimulator of the sugar receptor of the sensillae with a threshold of 10(-7) M; in combination with 0.2 M glucose, it inhibits impulse activity with the first 200 msec of stimulation. The effect is observed in a narrow zone of ouabain concentrations, with a maximum approximately at 10(-4) M. Differences between the effects of the inhibitor at the vicinity of the onset of generator potential and those in the impulse activity zones on the membrane of the sensory cell are suggested.     

Spike amplitude of single-unit responses in antennal sensillae is controlled by the Drosophila circadian clock

Circadian changes in membrane potential and spontaneous firing frequency have been observed in microbial systems, invertebrates, and mammals. Oscillators in olfactory sensory neurons (OSNs) from Drosophila are both necessary and sufficient to sustain rhythms in electroanntenogram (EAG) responses, suggesting that odorant receptors (ORs) and/or OR-dependent processes are under clock control. We measured single-unit responses in different antennal sensillae from wild-type, clock mutant, odorant-receptor mutant, and G protein-coupled receptor kinase 2 (Gprk2) mutant flies to examine the cellular and molecular mechanisms that drive rhythms in olfaction. Spontaneous spike amplitude, but not spontaneous or odor-induced firing frequency, is under clock control in ab1 and ab3 basiconic sensillae and T2 trichoid sensillae. Mutants lacking odorant receptors in dendrites display constant low spike amplitudes, and the reduction or increase of levels of GPRK2 in OSNs results in constant low or constant high spontaneous spike amplitudes, respectively. We conclude that spike amplitude is controlled by circadian clocks in basiconic and trichoid sensillae and requires GPRK2 expression and the presence of functional ORs in dendrites. These results argue that rhythms in GPRK2 levels control OR localization and OR-dependent ion channel activity and/or composition to mediate rhythms in spontaneous spike amplitude.     

External Structures of the Antennae and Mouth Parts of the Fourth Instar of Chironomus flaviplumus and Chironomus salinarius (Diptera: Chironomidae)

Chironomidae is usually the most abundant macroinvetebrate in freshwater. They form an important part of the foodweb, and also have long been known as indicators of water quality. However, there is a great deal of difficulty in its identification. Such is due to the complexity of larval taxonomy. The external fine structures of the mouth parts and antennae of 4th instar larva C. flaviplumus and C. salinarius were examined using scanning electron microscopy (SEM). The antennae of the fourth instar larvae of C. flaviplumus and C. salinarius are short and composed of five segments. They consist of a scape, pedical, and three flagellar subsegments. The maxilla palps have 10 sensilla basiconica on its distal surface. They show the three morphological groups in the following numbers: six apical sensillae, three medial sensillae, and one lateral sensillae. The mandibles have strong apical and lateral teeth. These sensory structures are situated on the head capsule, each of which are represented with images to elucidate the identification of chironomidae.     

The external morphology and distribution of cuticular hair organs on the claws of the American lobster, Homarus Americanus (Milne-Edwards)

Four classes of microscopic cuticular hair organs were found on the chelae of Homarus americanus (Milne-Edwards). Type I and Type II organs possess long single sensillae, 30–60 μm and 70–130 μm, respectively. Type III organs are toroid bumps 20–30 μm in diameter, with a small tuft of fibers projecting from the center. Type IV organs are small conical hairs ≈ 1 μm in length.Type IV organs were uniformly distributed over the claws. The distributions of Types I, II, and III organs were analysed through multivariate analysis of variance (MANOVA) with respect to claw, side, and area. Type I organs showed significance of the three-way interaction only. Type II organs showed significance of side, area, and the claw by area interaction. Type III organs showed significance of area, and all interactions. Changes in number and density of Types I, II and III organs, and in number of Type IV organs, were found with growth.     

Sensory apparatus of the cercaria of 2 species of the genus Apatemon (Trematoda: Strigeidae)

The sensory apparatus of cercariae of two species of trematodes (A. cobitidis and A. minor) is described. The species differ both morphologically and biologically. The only common feature in the sensory apparatus of the above species is the topography of sensillae in the posterior half of the lateral complex of the caudal trunk and of the furcal complex.     

Répercussion sur la prise de nourriture de désafferénces sensitives de la région péribuccale de la larve de Locusta

Nerves of Locusta to the labrum, mandible, and hypopharynx were cut. Each of these operations deprived the whole organ of sensory nerves without affecting motor function. In other experiments palps, antennae, and galeae were removed. Feeding behaviour is measured by weighing faeces produced. This behaviour is not affected for long by suppressing a considerable number of sensory sensillae and it would appear that feeding is not dependent simply upon sensory areas in the regions studied.     

Morphology of the antennal sensory cone in insect larvae from various orders

This article describes the morphology of antennae in larvae of three species of beetles from the families Cerambycidae and Chrysomelidae; one species of the caddis fly from the family Limnephilidae; and four species of dipterans from the families Culicidae, Chironomidae, and Muscidae. In all investigated species, the antenna has a sensory cone on it. Larvae of the caddis fly, longhorn beetles, and leaf beetles have on their antenna solitary sensillae and the sensory cone. This proves the advanced evolution of these species. Despite reduction of the head capsule, the antennal sensory cone in ±9/58 larvae of higher dipterans has become the dominant sensory structure.     

Elektronenmikroskopische Untersuchungen zum Problem der Sekretion der bindegewebigen Interzellularsubstanz

Zusammenfassung Die Sinnesorgane des Vorderendes von Linens ruber werden elektronen-mikroskopisch vor allem im Hinblick auf die rezeptorischen Strukturen untersucht. Am Kopfvorderrand liegen zwei Rezeptortypen: Typ 1 ist mit 20–40, Typ 2 nur mit einer Zilie besetzt. Die Seitenwurzeln der Zilien von Typ 1 sind parallel angeordnet. Die Perikarya beider Rezeptoren liegen unterhalb des Epithelverbandes, dessen Großteil von Typ 1 eingenommen wird. In den Kopfspalten finden sich primäre Sinneszellen mit eingesenkten Zilien, deren Membran regelmäßig aufgeschwollen ist. Im Cerebralorgan dominiert ebenfalls eine primäre Sinneszelle, die reichlich efferent innerviert wird. In den Lichtrezeptoren findet sich eine Zilie unter dem distalen Mikrovillisaum.Alle beschriebenen Zilien sind deutlich voneinander und von den Wimpern der Epidermis unterschieden. Sie werden mit den Zilien der Rezeptoren anderer Tiergruppen verglichen.

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The fine structure of the sensory organs of Lineus ruber O. F. Müller (Nemertini, Heteronemertini)

Summary The sensory organs located in the head reagion of the ribbon worm Lineus ruber have been investigated with the electron microscope. Attention has been focussed on the apical cell-structures, which are assumed to be related to sensory functions. At the anterior edge of the head two receptor-types occur: type 1 bears 20–40 apical cilia, type 2 only 1 cilium per cell. The lateral ciliary rootlets of type 1 are oriented strictly parallel. The pericarya of both receptor types of which type 1 is particularly dominant, are situated below the basement lamina of the epithelium. In the cephalic clefts primary sensory cells occur, the cilia of which are invaginated into the apical cytoplasm. Their ciliary membrane exhibits regular inflations. In the cerebral organ also primary sensory cells dominate which receive an abundant efferent nerve supply. In the light receptors only one cilium is to be found below the distal villi. The cilia of the sensory cells and also of the ordinary epidermis cells show individual characteristics not shared by the other types. Their structural peculiarities are compared with those of sensory organs of other groups of animals.

Herrn Prof. Dr. Drs. h. c. W. Bargmann zum 65. Geburtstag gewidmet.     

Ultra morphology of sensilla on the head and mouth parts of the earwig Anisolabis martima (Bonelli) (Dermaptera: Carcinophoridae)

The earwig Anisolabis maritima is a cosmopolitan insect with a worldwide distribution, omnivorous in feeding, eating the eggs of different insects. Recently recorded in Saudi Arabia as a beneficial predator on eggs and newly hatched larvae of the red palm weevil Rhyncophrous ferrugineus, scanning electron microscopy (SEM) observations revealed the presence of different kinds of receptor sensillae occurring on the head and mouth parts of A. maritime. The sensillae are the same, but differ in numbers on both sexes. The head surface bears three subtypes of trichoid sensillae, one type of ceoloconica. Labrum, labium, labial palps and maxillary palps, possess different kinds of sensillae. Three subtypes of trichoid have been identified on the labrum. The labium contained one type of tricoid and basiconic sensillae. There are great numbers and numerous sensillae cheatica differing in length distributed on the maxillary and the labial palps on all segments between other stutter spines. The last terminal segment of maxillary or labial palps bears the greatest number of the sensillae cheatica. Adult A. maritima may be introduced in the future as a beneficial predator of eggs of R. ferrugineus as a tool for integrated pest management.