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Sökning: hsv:(NATURVETENSKAP) hsv:(Biologi) hsv:(Zoologi) > Hallberg Eric

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1.
  • Hallberg, Eric, et al. (författare)
  • Sensilla and Proprioceptors
  • 2003
  • Ingår i: Handbook of Zoology, Vol. IV. Part 36. Lepidoptera, moths and butterflies. Vol. 2., Morphology, physiology, and development.. - 3110162105 ; , s. 267-288
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
    • Abstract is not available
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2.
  • Kristoffersen, Lina, et al. (författare)
  • Sparse sensillar array on Trioza apicalis (Homoptera, Triozidae) antennae—an adaptation to high stimulus levels?
  • 2006
  • Ingår i: Arthropod Structure & Development. - : Elsevier BV. - 1467-8039. ; 35:2, s. 85-92
  • Tidskriftsartikel (refereegranskat)abstract
    • To investigate the morphological basis for olfactory reception in the carrot psyllid (Trioza apicalis) we used scanning and transmission electron microscopy. Our study reveals a very sparse sensillar setup. We identify and describe several different types of single-walled sensilla likely to have an olfactory function, as well as mechanosensory hairs and intracuticular sensilla. A T. apicalis antenna is about 0.6 mm long and has 10 segments. Apically on the flagellum there are two conspicuous multi-porous single-walled bristles. There are six cuticular cavities on the flagellum; two smaller on the apical flagellomere, and four larger located on the lateral side of the antenna on flagellomeres 2, 4, 6 and 7. Each cavity contains two sensilla and there are three varieties of cavity sensilla. Mechano- and chemosensory hairs appear in low numbers on all segments but the third. Carrot psyllids most likely use olfactory cues to locate their rather strongly smelling host plants, and we argue that the low number of olfactory sensilla found in this insect may accommodate high concentrations of odour stimuli. There is no sexual dimorphism in the sensillar setup. In concordance with this, no sex pheromones have been described in the Psylloidea so far.
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3.
  • Larsson, Mattias C, et al. (författare)
  • Specialized olfactory receptor neurons mediating intra- and interspecific chemical communication in leafminer moths Eriocrania spp. (Lepidoptera: Eriocraniidae).
  • 2002
  • Ingår i: Journal of Experimental Biology. - 1477-9145. ; 205:7, s. 989-998
  • Tidskriftsartikel (refereegranskat)abstract
    • We performed a physiological and morphological characterization of sensilla auricillica in male Eriocrania semipurpurella moths. Each auricillic sensillum contained three olfactory receptor neurons. Responding neurons (87 of 139) could be grouped into five physiological types. Type 1 responded to (R,Z)-6-nonen-2-ol and type 2 to its enantiomer (S,Z)-6-nonen-2-ol, both of which are pheromone components of E. semipurpurella. Type 3 responded to both (R)-heptan-2-ol and (R,Z)-4-hepten-2-ol, which are pheromone components of the sympatric species E. cicatricella. Types 4 and 5 responded to the ketones (Z)-6-nonen-2-one and/or nonan-2-one, which are found in the pheromone glands of female E. semipurpurella. Field-trapping showed that type 3 receptor neurons mediate strongly antagonistic effects of (R)-heptan-2-ol and (R,Z)-4-hepten-2-ol on E. semipurpurella, while nonan-2-one should possibly be included as a synergist in the sex pheromone blend of this species. The attraction of E. cicatricella and E. sparrmannella to compounds mixed with the pheromone blend of E. semipurpurella shows that the pheromone components of E. semipurpurella have little or no antagonistic effects on these species. The morphology and physiology of eriocraniid pheromone sensilla are very similar to those found in the order Trichoptera (caddisflies), suggesting a homology between pheromone detection systems in the two sister orders Lepidoptera and Trichoptera.
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4.
  • Kozlowsky-Suzuki, Betina, et al. (författare)
  • Glutathione transferase activity and oocyte development in copepods exposed to toxic phytoplankton
  • 2009
  • Ingår i: Harmful Algae. - : Elsevier BV. - 1878-1470 .- 1568-9883. ; 8:3, s. 395-406
  • Tidskriftsartikel (refereegranskat)abstract
    • Organisms present a series of cellular mechanisms to avoid the effects of toxic compounds. Such mechanisms include the increase in activity of detoxification enzymes [e.g., 7-ethoxyresorufin-O-deethylase (EROD) and glutathione S-transferase (GST)I, which could explain the low retention of ingested toxins generally observed in copepods. In addition, decreasing gross growth efficiency (GGE) of copepods with increasing concentration of toxic diets could be caused either by a high expenditure coping with toxins (e.g., increase in the activity of detoxification enzymes) or by a deterioration of reproductive tissues. To assess the effect of toxic phytoplankton on the activity of detoxification enzymes and on oocyte maturation of Acartia tonsa and Temora longicornis, feeding and egg production experiments were carried out with a variety of toxic diets and an adequate non-toxic food control (Rhodomonas spp.) all provided as single species diets. Toxic diets included the nodularin-producing cyanobacterium Nodularia spumigena, the dinoflagellates Alexandrium minutum, and A. tamarense, which contained Paralytic Shellfish Poisoning (PSP) toxins, the dinoflagellate Prorocentrum lima with Diarrhetic Shellfish Poisoning (DSP) toxins and the haptophyte Prymnesium parvum, which produces ichtyotoxins with haemolytic activity. Feeding on toxic diets was lower than on Rhodomonas spp., except for A. minutum and A. tamarense. In addition, toxic diets negatively affected reproduction in both copepod species with the production of oocytes and oocyte development impaired with A. minutum and N. spumigena. While the negative effect of N. spumigena seemed to be connected to gonad atresia likely caused by severe food limitation (starvation), the negative effect of A. minutum could have been either caused by a direct effect of saxitoxins or nutritional inadequacy on oocyte production. We could not detect EROD activity in the copepods, while the activity of GST was generally higher with the non-toxic food control and positively related to the feeding and egestion rates, suggesting relation to feeding conditions rather than to exposure to toxic diets. No relationship was found between GGE and CST activity. Our results refute the hypothesis that toxic diets, provided at ecologically relevant levels, would induce cellular mechanisms in copepods regarding GST activity. GST activity thus seems to play no role in detoxification of copepods confronted with toxic phytoplankton. Toxin detoxification and its cost for copepods still remain an open question. (C) 2008 Elsevier B.V. All rights reserved.
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5.
  • De Facci, Monica, et al. (författare)
  • Flagellar sensilla of the eusocial gall-inducing thrips Kladothrips intermedius and its kleptoparasite, Koptothrips dyskritus (Thysanoptera: Phlaeothripinae)
  • 2011
  • Ingår i: Arthropod Structure & Development. - : Elsevier BV. - 1467-8039. ; 40, s. 495-508
  • Tidskriftsartikel (refereegranskat)abstract
    • Insect antennal flagella host a multitude of sensory organs fulfilling different functions. Chemoreception, for example, is essential for insects in many contexts. Both olfaction and contact chemoreception are involved in host-plant selection, as well as in the integrity of insect societies, especially for nestmate recognition. Kladothrips intermedius is a eusocial gall-inducing thrips with two castes: dispersers and soldiers. Koptothrips dyskritus is a specialist in invading Kl. intermedius galls, killing the occupants, and thereby gaining the food and shelter offered by galls. In this study, we compared the morphology and ultrastructure of the flagellar sensilla of Kl. intermedius and Ko. dyskritus via scanning and transmission electron microscopy in order to facilitate future investigations of their sensory ecology, with an emphasis on chemical ecology. The two species show a very similar sensillar array. There are a few mechanosensory trichoid and a second type of mechanosensory sensilla, thermo-hygroreceptive sensilla, olfactory single-walled basiconic and double-walled coeloconic sensilla as well as contact chemoreceptive chaetic sensilla. The latter are sexually dimorphic in Kl. intermedius. Dispersers and soldiers of Kl. intermedius do not present noteworthy morphological differences, but the ultrastructural investigations revealed that soldiers have fewer ORNs, possibly an adaptation to their gall-cloistered lifestyle.
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6.
  • Ekerholm, Mattias, et al. (författare)
  • Primer and short-range releaser pheromone properties of premolt female urine from the shore crab Carcinus maenas
  • 2005
  • Ingår i: Journal of Chemical Ecology. - : Springer Science and Business Media LLC. - 1573-1561 .- 0098-0331. ; 31:8, s. 1845-1864
  • Tidskriftsartikel (refereegranskat)abstract
    • The European shore crab Carcinus maenas is considered to rely on a female pheromone when mating. Evidence, however, is scarce on how the urine pheromone in itself affects males. We investigated male primer and releaser responses to female pheromones with methods that minimized effects from females, delivering female urine either as a pump-generated plume or deposited on a polyurethane sponge. We delivered the pheromone at different concentrations in far, near, and close/contact range to get a picture of how distance affects behavioral response. Our results show that substances in premolt female urine (PMU) function as primer and potent short-range releaser pheromones. Based on the olfactometer and sponge tests, we conclude that PMU stimulus in itself is sufficient to elicit increased search and mating-specific behaviors such as posing, posing search, cradle carrying, and stroking. Pheromone concentrations do not seem to be important for attenuating search and posing as long as the level is above a certain threshold concentration. Instead, pheromone levels seem to play a role in male acceptance of females, recruiting more males to respond, and generating better responses with increasing concentration.
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7.
  • Elofsson, Rolf, et al. (författare)
  • Compound eyes of some deep-sea and fiord crustaceans
  • 1977
  • Ingår i: Acta Zoologica. - : Wiley. - 0001-7272 .- 1463-6395. ; 58, s. 169-177
  • Tidskriftsartikel (refereegranskat)abstract
    • The compound eyes of the deep-sea mysid Boreomysis scyphops and the two mysid species Amblyops abbreviata and Pseudomma affine, which are indigenous to deep fiords in Norway, have been investigated. The eye stalks are greatly transformed, but contain hypertrophied retinas. The ommatidia of all three species lack a dioptric apparatus, possessing only retinular cells, which are arranged in a cylinder-like fashion. Folds from the retinular cells project into the “cylinder” and are covered with microvilli. The arrangement is explained functionally by an increase in the photopigment-bearing surface as an adaptation to low-light intensities. The orderly arrangement of microvilli in most arthropod compound eyes has been lost, and the arrangement is thus multidirectional in these mysids. With the photopigment dipoles arranged along the microvillar axis, the disorderly arrangement of microvilli signifies a more efficient capture of non-polarized light. It is concluded that the mysid compound eyes show adaptations to low-light intensities probably acquired during the species' evolutionary descent into deep-sea habitats. Amblyops abbreviata and Pseudomma affine, belonging to genera with entirely transformed eyes and with an ultrastructure less “normal” than that of Boreomysis scyphops are believed to be earlier descendants into the deep-sea habitats than the latter species, which belongs to a genus in which most of the species have well-developed eyes.
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8.
  • Elofsson, Rolf, et al. (författare)
  • Correlation of ultrastructure and chemical composition of crustacean chromatophore pigment
  • 1973
  • Ingår i: Journal of Ultrastructure Research. - 0022-5320. ; 44, s. 421-429
  • Tidskriftsartikel (refereegranskat)abstract
    • Chromatophores, with chemically identified pigment, from the body and eyes of crustaceans were investigated ultrastructurally. Red carotenoid-, black ommochrome-, and white pteridine-containing chromatophores were found to have pigment granules of different morphological appearance.
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9.
  • Garm, A, et al. (författare)
  • Role of maxilla 2 and its setae during feeding in the shrimp Palaemon adspersus (Crustacea : Decapoda)
  • 2003
  • Ingår i: Biological Bulletin. - 0006-3185. ; 204:2, s. 126-137
  • Tidskriftsartikel (refereegranskat)abstract
    • The movements of the basis of maxilla 2 in Palaemon adspersus were examined using macro-video recordings, and the morphology of its setae was examined using both scanning and transmission electron microscopy. The basis of maxilla 2 performs stereotypical movements in the latero-medial plane and gently touches the food with a frequency of 3-5 Hz. The medial rim of the basis of maxilla 2 carries three types of seta. Type 1 is serrate, type 2 and 3 are serrulate, and type 2 has a prominent terminal pore. Type 2 is innervated by 18-25 sensory cells whose cilia protrude through the terminal pore and are in direct contact with the external environment. The structure of type 2 setae indicates that they are mainly gustatory, although still bimodal due to their innervation by presumed chemosensory and mechanosensory neurons. Distally, the three types of setae have a complex arrangement of the cuticle involving water-filled canals, which may serve to improve flexibility. Type I and 3 setae have fewer sensory cells (4-9) but probably also have a bimodal sensory function. The function of type I setae is probably to protect type 2 setae, while type 3 setae might serve to groom the ventral side of the basis of maxilla 1.
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10.
  • Hallberg, Eric, et al. (författare)
  • An ascothoracid compound eye (Crustacea)
  • 1985
  • Ingår i: Sarsia. - : Informa UK Limited. - 0036-4827. ; 70, s. 167-171
  • Tidskriftsartikel (refereegranskat)abstract
    • The ultrastructure of the compound eye of an ascothoracid larva — the only known occurrence of compound eyes in the Ascothoracida — is described. The ommatidia of apposition type consist of a crystalline cone composed of three cells and up to six retinular cells. Poor fixation of the scarce material allows no safe judgement about the number of retinular cells and the nature of two distal cells surrounding the crystalline cones. The structure of these compound eyes most closely resembles the cirriped compound eye.
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