. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 106 J. WOODLAND HASTINGS AND JOHN BUCK flash of Photinus pyralis, and that when intact fireflies are tested with progressively falling oxygen concentration the spiracles open well before the hypoxic glow begins and close after it ceases. Evidence that the spiracles have no immediate influence on the hypoxic glow-pseudoflash response was obtained in the present study by testing adults of Photuris and Photinus in which the spiracles of the luminous segments had been made inoperative by cautery with an electrically heated needl
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 106 J. WOODLAND HASTINGS AND JOHN BUCK flash of Photinus pyralis, and that when intact fireflies are tested with progressively falling oxygen concentration the spiracles open well before the hypoxic glow begins and close after it ceases. Evidence that the spiracles have no immediate influence on the hypoxic glow-pseudoflash response was obtained in the present study by testing adults of Photuris and Photinus in which the spiracles of the luminous segments had been made inoperative by cautery with an electrically heated needle or by insertion of a short length of human baby hair. Although these specimens often showed a continuous glow in air, presumably caused by the mechanical dis- 100 r CO £ 50 h- x o J. 8 5 10 15 % OXYGEN 20 FIGURE 4. Relation between oxygen concentration and glow intensity (in per cent of in- tensity in air) of smeared photogenic tissue of males of P. pyralis. Data from several experiments. turbance, they gave pseudoflashes similar to those in individuals with normal spiracles. Likewise, it was observed that spiracular opening is regularly induced by exposure to 5% oxygen, whereas the hypoxic glow usually requires that the ambient oxygen concentration be reduced to the order of 1% to 2%. Absence of spiracular or in- deed any sort of valvular influence is also seen in dead fireflies which, if prevented from drying out, may exhibit a constant dim air glow for a day or more after all visible signs of life have disappeared. Such dead specimens have permanently open spiracles yet give a pseudoflash response. A series of experiments was performed in which increasing degrees of interfer-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
