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  • 1995-1999  (3)
  • 1985-1989
  • 1995  (3)
Materialart
Erscheinungszeitraum
  • 1995-1999  (3)
  • 1985-1989
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Experimental and applied acarology 19 (1995), S. 287-306 
    ISSN: 1572-9702
    Schlagwort(e): Ticks ; Hyalomma truncatum ; spiracles ; morphology ; structural organization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Scanning electron microscopical investigations of fractures and corrosion casts of spirales in adult ticks of Hyalomma truncatum revealed a three-part structure consisting of the spiracular plate forming the outer part followed by the subostial space, which leads into the atrial chamber from which the main tracheal trunks arise. The spiracular plate sonsists of a thin surface plate perforated by aeropyles, an underlying interpedicellar space formed by pedicels and an inner thick base plate. The surface plate is subdivided into a porous and a non-porous area. The macula is surrounded by the porous area and cleft by the ostium, which is bounded by a lip. The lip rests on a stalk which passes through the subostial space and forms the lateral wall of the atrial chamber. The interpedicellar space is chambered comprising four types of chambers. Large pyriform chambers (type 1) open to the atmosphere via a large aeropyle and are connected at their base with a duct traversing the base plate. They correspond numerically and in their position with the large aeropyles and the ducts of the base plate. Each chamber is surrounded by four to six medium-sized tubular chambers (type 2) which are closed at both ends. Small tubular chambers (type 3) open to the atmosphere via a small aeropyle, are closed at their base and correspond in number and position to the small aeropyles. Elongated chambers (type 4) are arranged in two to three rows around the subostial space and are closed at both ends. The front row communicates with the subostial space via large gaps. All chambers interconnect with each other by slit-like fenestrations. Below the macula and surrounding the stalk is the subostial space. Over the medial half, the subostial space opens into the atrial chamber. The lateral wall of the atrial chamber is thick, whereas the opposite wall is thin, folded and can be everted and inverted. Inverted, the medial wall closes up the opening to the subostial space and the main tracheal trunks. The base of the atrial chamber sonsists of the openings of the main tracheal trunks only. It is concluded that the aeropyles constitute the functional openings of a spiracle, the interpedicellar space and the subostial space act as diffusion barrier and the atrial chamber is exclusively responsible for the motory process of in- and expiration and is the only closing device of the spiracle.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Experimental and applied acarology 19 (1995), S. 155-161 
    ISSN: 1572-9702
    Schlagwort(e): Ticks ; Hyalomma truncatum ; coloured objects ; monochromatic light ; perception ; differentiation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Behavioural investigations into the perception and differentiation of coloured objects by unfed adult Hyalomma truncatum ticks revealed that silhouettes of blue, green, red and yellow colour, under illumination by a sun-simulating waveband spectrum, are perceived by the ticks and responded to equally by a directed response. Two green or dark grey rectangles each with a luminance contrast ratio of 5 : 1 against the white wall of the test arena in combination with an overlapping, equally sized dark grey or green target were consistently reached by ticks in a ratio of 2 : 1. Since the outer targets were occupied by the double number of ticks compared with the central silhouette this shows that the response is independent of the colour of the object. Investigations into target perception under monochromatic radiation of different wavelength ranges which were evenly adjusted in their irradiances revealed that ticks responded equally to a black target irradiated by blue, green, yellow and red light of wavelengths 428–472, 517–563, 549–591 and 606–654 nm, respectively. These results indicate the lack of true colour vision in H. truncatum.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Experimental and applied acarology 19 (1995), S. 53-64 
    ISSN: 1572-9702
    Schlagwort(e): Ticks ; Hyalomma truncatum ; visual behaviour ; scototaxis ; CO2 gradient ; temperature gradient
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Under controlled test conditions, unfed male and female Hyalomma truncatum ticks exhibited a positive scototaxis to stationary, two-dimensional targets. Upright-positioned rectangles were the most attractive targets. The attractiveness of these targets increased with their size. Significantly more ticks responded scototactically positively to the targets under a luminance contrast ratio of 5:1, as compared with other luminance contrast ratios. Targets with an elevation angle of 13° were occupied more frequently than objects with higher elevation angles. Scototaxis was the same towards a stationary and a sinusoid oscillating target. When an upright-positioned rectangle was combined with a CO2 gradient, the number of ticks that migrated into the CO2 gradient and contacted the target did not increase significantly. The interval between exposure and first locomotion of the ticks, however, was significantly shorter under the influence of a CO2 gradient than in all other experiments without a CO2 gradient. A temperature gradient simulating a natural host (cattle) did not alter the scototaxis. The results of these investigations suggest that the positive scototaxis exhibited by adult H. truncatum ticks is not likely to be part of their appetence behaviour but rather searching behaviour to find adequate protection from harsh climatic conditions.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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