Effects of xanthines and colchicine on the longevity, photoconductive properties and yellow pigment structure of the Oriental hornet Vespa orientalis L.
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Biomedical subjects
T B Shimony
Publications and source records attributed to T B Shimony.
Pigment granules in the tegumental yellow strips of social wasps: a scanning electron microscopic study.
In social wasps the yellow pigment assumes the shape of quasi-cylindrical granules 0.6...0.8 microm long and 0.3...0.4 microm in diameter. These are mostly concentrated around the bases of the funnel-like cuticular sheath containing the cellular elements of the sense organ. Feeding colchicine to the wasps induces degeneration of the granules but the addition of xanthines to their diet render them refractory to the destructive action of colchicine. Changes in the size and shape of the granules with age and following continuous illumination are described.
Animals↗
Capacitance in ant cuticle is frequency dependent: a statistical model.
The capacitance and the electric resistance of the cuticle of the ant Cataglyphis bicolor nigra Andr é (Hymenoptera, Formicinae ) were measured. The measurements were done at the frequencies 100 Hz and 1000 Hz and at a temperature range of 27.5-45 degrees C. Inverse correlation was observed between the capacitance and the frequency, so that at the higher frequency the capacitance was lower. Thus, in some instances, at 1000 Hz the capacitance ranged between 0.49 and 2. 16nF , while at 100 Hz it ranged between 5.74 and 19. 39nF at the measured temperature range. A similar inverse correlation was detected also between the resistance and the frequency. At 1000 Hz, the resistance values in some specimens ranged between 0.166 and 0.278 M omega whereas at 100 Hz they varied between 0.342 and 0.883 M omega. At both frequencies measured there was a temperature-dependence of the capacitance and of the electric resistance. With increase in temperature there was increase in the capacitance and a decrease in the resistance. Invariably, the trend of cuticular behavior was similar under cooling as under warming, but the values differed, creating a gap (hysteresis). Under cooling the resistance values were higher and the reverse was true for the capacitance. A statistical model is offered which graphically describes the behavior of the ant cuticle (resistance and capacitance) under changes in temperature and frequency. X-ray analysis of the cuticle revealed the presence of Ca as the most prominent element. Additional elements, but less prominent were P, S and K. It also contains Fe and Zn. The finding of a correlation between the capacitance and the frequency might lead to the following conclusions: that the measured system contains polarized substances; that the measured value in each case represents a resultant of values obtained from the measurement of more than one electrical circle (and probably more than one network of electrical circles); and that possibly a combination of (a) and (b) prevails. Presumably these changes in the capacitance and resistance at different temperatures and frequencies indicate that the ant cuticle is capable of responding to changes in the physical ambience , thus promoting proper ant spatial orientation and the pursuant behavior.
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