Some effects of low oxygen partial pressures on the development of Calliphora vomitoria

Abstract

The influence of wet conditions and low pO 2 on the survival and development of non-feeding final instar larvae and puparia of Calliphora vomitoria has been investigated. The larvae delay the formation of the puparium in wet conditions in air and in dry or wet conditions in 10 and 5% oxygen. This may be related to the susceptibility of the newly formed puparia to oxygen shortage. The pupal respiratory horns play an important part in maintaining O 2 uptake when the puparia are surrounded by particles covered with a film of water but are not involved in aiding survival in low pO 2. Zero age puparia are killed by a 2 day exposure to 10% O 2 but later stages can continue to develop in this gas. Fifty per cent of the 0, 1 and 9 day old puparia are killed by about a 12 hr exposure to 1% O 2 whereas 50 per cent of the 2 to 8 day old puparia can survive over 1·5 days exposure to this gas. Development, as measured by respiration rates and the timing of the emergence of the adults, is delayed by 1% O 2 by the amount of time that the insects spend in that gas. However, the first phase of elongation of the pharate adult longitudinal flight muscle, occurring between the third and fourth day of puparial life, is only slightly slowed down in 1% O 2. The variations in susceptibility to 1% O 2 and the growth of the muscles are discussed in relation to published accounts of protein synthesis in the puparium.