. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 510 HOWARD A. SCHNEIDERMAN and after an initial spiracular burst, no further bursts occurred. The openings were a bit larger than normal interburst flutterings, but much smaller than normal open- ings in a burst. The reaction times for a carbon dioxide response never appeared as long as the reaction times for a response to oxygen. Also, pupae with high metabolic rates, and hence frequent bursts, appeared far more sensitive to carbon dioxide than pupae with low metabolic rates. Thus, in a pupa which had a 4- to 5-minute burst
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 510 HOWARD A. SCHNEIDERMAN and after an initial spiracular burst, no further bursts occurred. The openings were a bit larger than normal interburst flutterings, but much smaller than normal open- ings in a burst. The reaction times for a carbon dioxide response never appeared as long as the reaction times for a response to oxygen. Also, pupae with high metabolic rates, and hence frequent bursts, appeared far more sensitive to carbon dioxide than pupae with low metabolic rates. Thus, in a pupa which had a 4- to 5-minute burst cycle, as little as 2% carbon dioxide had a detectable effect on spiracular behavior (pro- longed the burst), while 3% eliminated spiracular bursts and provoked continuous wide flutters. Furthermore, when the carbon dioxide tension was raised to 15% in a pupa with such a brief cycle, the valves opened widely, and nearly a half hour AIR IMIN. I0 20 30 I5%C02 40 50 60. 90 100 110 FIGURE 9. Records of spiracular movements of a Polyphemus pupa with frequent bursts in air, in 15% CO» + 21% O2, and in air. was required for recovery upon return to air (Fig. 9). Such sensitivity to carbon dioxide contrasts markedly with the more modest responses recorded in Figure 8, shown by a pupa with a longer burst cycle. A further observation important to our analysis is that in a pupa in which 3% carbon dioxide eliminated the spiracular bursts, bursts could be restored in 3% CO2 by raising the oxygen tension to about 90%. This observation suggests that high oxygen tensions decrease the sensitivity of the spiracle to carbon dioxide, a fact to which we shall return. Although these results convey a general picture of the effects of carbon dioxide and oxygen on the pupal spiracles, they suffer from a conspicuous defect: they provide only little information about the actual gas concentrations within the tracheal system that produce a particular effect. In other words, when the insect. Please note th
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
