. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DIAPAUSE DEVELOPMENT 181 over the administration of a single massive dnse. The addition of different amounts of ammonium acetate to the larval rearing medium did not reduce the incidence of diapause among borer larvae reared under a short-day photoperiod. A possible explanation for the ammonium effect on diapause development is that ammonium ions are required for the synthesis of other nitrogenous compounds, and a massive influx of ammonium forces the synthetic process to an effective nondiapause rate of production. Accordin
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DIAPAUSE DEVELOPMENT 181 over the administration of a single massive dnse. The addition of different amounts of ammonium acetate to the larval rearing medium did not reduce the incidence of diapause among borer larvae reared under a short-day photoperiod. A possible explanation for the ammonium effect on diapause development is that ammonium ions are required for the synthesis of other nitrogenous compounds, and a massive influx of ammonium forces the synthetic process to an effective nondiapause rate of production. According to this hypothesis, administration of the biochemical substrates actually involved in the synthesis would be effective at greatly reduced concentrations. In pursuing this hypothesis, we have tested a large number of amino and other nitrogenous compounds, but with uniformly negative results. Carbamyl phosphate, tryptamine, 5-hydroxytryptamine, several 100 90 80 70 z o H 60 < a 250 z u O 30 ct UI a 20 10 UNTREATED AND LD. 0 5 10 15 20 25 30 35 40 45 DAYS POSTTREATMENT FIGURE 1. The combined effects of ammonium acetate (400 /^) and photoperiod on diapause development in the European corn borer. (Untreated dark control record not plotted, because none pupated.) amino acids, urea cycle intermediates, RXA synthesis intermediates, proline cycle intermediates, and several others have been tested. This aspect of the problem is under current investigation, but for the present we know the response only as the "ammonium ion effect.'' Combined ammonium and photoperiodic effects. Ammonium ions accelerate diapause development, and long-day photoperiods exert the same effect. There may, therefore, be an interaction between the two accelerating factors. This hypothesis was tested in a series of experiments in which suboptimal doses of ammonium acetate were administered to diapause larvae, which were then held for pupation under either a long-day photoperiod or continuous dark
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
