. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SPIRACLES IN CYCLICAL RESPIRATION 509 A AIR IMIN. 10 !..,>«- „ . f - 50 60 ... .. 90 100 110 120 130 140 150 160 170 B IMIN. 10 20 30 I5%C02 40 A i • »• "** »!!•«>• n » ^ », I., ,^- „ - - V1 -r r i- .»«%. •.•.». • • i .».!.•.... ffl'H^^ini . * »».«(1m. n ^ r-nl *• 50 60 70 80 90 ,,, ^. .• - ... ^—~ i- .... r,.^n ,, , liaii ..j,!! '"^iVSiii __^ ... ,_ ,_^i b '20 _ I, 140 ISO 160 170 180 190 FIGURE 8. Records of spiracular movements of a Cecropia pupa with a moderately long burst cycle in air, followed b
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SPIRACLES IN CYCLICAL RESPIRATION 509 A AIR IMIN. 10 !..,>«- „ . f - 50 60 ... .. 90 100 110 120 130 140 150 160 170 B IMIN. 10 20 30 I5%C02 40 A i • »• "** »!!•«>• n » ^ », I., ,^- „ - - V1 -r r i- .»«%. •.•.». • • i .».!.•.... ffl'H^^ini . * »».«(1m. n ^ r-nl *• 50 60 70 80 90 ,,, ^. .• - ... ^—~ i- .... r,.^n ,, , liaii ..j,!! '"^iVSiii __^ ... ,_ ,_^i b '20 _ I, 140 ISO 160 170 180 190 FIGURE 8. Records of spiracular movements of a Cecropia pupa with a moderately long burst cycle in air, followed by 10% or 15% (A) 10% CO2; (B) 15% In occasional experiments, particularly with pupae with high metabolic rates and frequent bursts, pure oxygen failed to suppress interburst fluttering. Instead the spiracular bursts disappeared and the spiracles fluttered continuously. Possible reasons for this curious behavior will be offered in the Discussion. 5. Effects of carbon dioxide tension Increasing the PCo2 increased burst frequency and lengthened both "open" and "decline" phases of the cycle (Table IV and Fig. 8). Besides the effect on burst frequency, the table and figure reveal that high tensions of carbon dioxide also lengthened both the open phase of the spiracular burst and the decline phase after the burst. Thus, in 10% carbon dioxide, the open phases were nearly three times as long as in air (compare Figure 7D with 7B). In addition, although increasing PCo2 nad little effect on the duration of the constriction period, it greatly shortened the flutter period until, in 10% carbon dioxide, fluttering was reduced to only a few minutes (Fig. 8). Between 10 and 15% carbon dioxide the burst cycle broke down completely, so that in 15% carbon dioxide the valves fluttered continuously (Fig. 8),. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
