W. N. Sullivan

Delay and acceleration of breaking diapause of Antheraea pernyi and Laspeyresia pomonella by photoperiod manipulation

Abstract Diapause of pupae of a silkworm, Antheraea pernyi Guerin-Meneville, was invariably terminated by exposure to cycles of 16 hours of light and 8 hours of darkness. When 15 minute light breaks were introduced during each 8 hour dark period at 21 hours after the beginning of the 16 hour photophase, 33 percent of the pupae did not break diapause. Diapause was broken in 67 percent of the pupae maintained in complete darkness. A similar light break introduced during a 12 hour dark period and a light break of one hour during a 14 hour dark period were not effective. Larvae of the codling moth, Laspeyresia pomonella (L.) had a similar pattern of response, but the percentage breaking diapause was always less. A biochemical mechanism which provides a possible explanation of the results with the oak silkworm is presented.

Photoperiod manipulation to control diapause in the pink bollworm,Pectinophora gossypiella

Im 12-h Kurztag gehaltenePectinophora gossypiella gehen zu 78% in Diapause. Zusätzlich applizierte, einstÜndige Perioden mit 15 Lichtpulsen von je 1 min Dauer reduzieren die Diapauserate. Die besten Resultate ergeben 2 Pulsperioden, je 1,5 h vor und nach der Hellphase appliziert.

The Survival of the Madeira Cockroach in Various Atmospheres

The Madeira cockroach ( Leucophaea maderae (F.)) has characteristics that should make it useful for biological studies on factors affecting life in outer space. In studies to determine a favorable atmosphere for survival in satellites the insects were sealed in 12-ounce containers with oxygen, nitrogen, helium, or mixtures of these gases but without food or water. Lithium hydroxide was used to absorb the carton dioxide evolved in most of the tests. The survival time was short with very low or with very high concentrations of oxygen. An atmosphere containing 55% to 58% of oxygen and 42% to 45% of nitrogen by volume appeared to be near optimum for the survival of the cockroaches, probable vided carbon dioxide was removed. The gradual reduction in the partial pressure as oxygen was utilized by the insects probably was a factor in the decrease of activity of the cockroaches and in the increase of their survival time.