. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. INSECT DIAPAUSE TERMINATION 87 The oxygen consumption of laboratory-reared borers was carried out using standard manometric techniques (Umbreit et al., 1957). Borer larvae were con- fined in small wire cages in each Warburg flask. This prevented them from crawling into the center well and, because the insect is thigmotactic, also tended to keep them relatively inactive. The oxygen consumption of each larva was measured for one hour in 10-minute increments. The p\. O2 consumed per hour was divided by the live weight of the in
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. INSECT DIAPAUSE TERMINATION 87 The oxygen consumption of laboratory-reared borers was carried out using standard manometric techniques (Umbreit et al., 1957). Borer larvae were con- fined in small wire cages in each Warburg flask. This prevented them from crawling into the center well and, because the insect is thigmotactic, also tended to keep them relatively inactive. The oxygen consumption of each larva was measured for one hour in 10-minute increments. The p\. O2 consumed per hour was divided by the live weight of the insect to give /«,!. O2 The analyses of variance were calculated by the method of Steel and Torrie (1960) for groups with unequal replication. Duncan's New Multiple Range test 9 HR PHOTOPHASE 13 HR PHOTOPHASE. 10 20 30 40 50 LARVAL AGE IN DAYS 60 70 80 FIGURE 2. Pupation curves for European corn borer populations reared under different photoperiods. The arrow indicates the time at which all diapause larvae were exposed to long- day photoperiods (). was used with the approximation of Kramer (cited in Steel and Torrie, 1960) for testing means based on unequal replication. RESULTS AND DISCUSSION The diapause stage in most insects is characterized by a low level of oxygen con- sumption (Heller, 1926; Boell, 1935; Schneiderman and Williams, 1953). Beck and Hanec (1960) found that the respiration of borers collected from the field also dropped, but little was known about the length of time necessary to reach this low level of oxygen consumption as the borers entered diapause. The "incipient" diapause reported by Beck and Apple (1961) may have reflected an incomplete suppression of respiration. Once a stable low level of oxygen consumption was reached, the "true" diapause stage would have been attained. Figure 1 shows that oxygen consumption declined after the moult from the fourth to the fifth instar in both diapause and nondiapause borers. The no
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
