Selective toxicity of 1 atmosphere of oxygen during morphogenesis of two Lepidopterans.

Continuous and interval exposures to 1 atmosphere of oxygen (hyperoxia) were examined using insects. Hyperoxia did not affect hatchability of Heliothis zea or Trichoplusia ni. Continuous hyperoxia was 100% lethal for H. zeal and T. ni. Most insects died as larvae and pupae of H. zea which resulted were deformed, reduced in weight, and failed to emerge. Hyperoxic exposures of T. ni for 48 h at sequential 48-h intervals during development, revealed that first instar and prepupae were most sensitive to hyperoxia and 80% were killed when exposed to only 24 h of hyperoxia as prepupae. T. ni which survived hyperoxia exposures at all development stages tested, were capable of producing progeny. The differential hyperoxic sensitivity and its correlation with specific morphogenetic stages suggest the usefulness of these insect species for studying biochemical sites of oxygen toxicity.