High‐dose mode of death in Tribolium

Abstract

This study reports the first demonstration within a single insect genus (Tribolium) of both the acute, or lethal-midlethal, dose-independent pattern of mortality, and the hyperacute, dose-dependent pattern, after appropriate doses of ionizing radiation. This demonstration provides resolution of apparently contradictory reports of insect responses in terms of doses required to cause lethality and those based on survival time as a function of dose. A dose-dependent mortality pattern was elicited in adult Tribolium receiving high doses, viz., 300 Gy or greater; its time-course was complete in 10 days, before the dose-independent m~rtality began. Visual observations of heavily-irradiated Tribolium suggested neural and/or neuromuscular damage, as had been previously proposed by others for lethally-irradiated wasps, flies, and mosquitoes. Results of experiments using fractionated high doses supported the suggestion that the hypeIacute or high-dose mode of death is the result of damage to nonproliferative tissues. Relative resistance of a strain to the hyperacute or high-dose mode of death is not necessarily correlated with resistance to the midlethal mode, which is believed to be the result of damage to the proliferative cells of the midgut.

Real-time phase-contrast x-ray imaging: a new technique for the study of animal form and function

“…One major difference between the grasshoppers and all other insects studied is that, because of their large size, only a part of the grasshopper's head was irradiated as opposed to the entire head in the other taxa. We note that, consistent with other studies [11,12,23], the loss of locomotor abilities observed in the insects at lower dosages was temporary, indicating radiation-induced lethargy. In many individuals, we observed recovery minutes to hours later, suggesting that radiation damage was at least partially repairable.…”

Morphological deformities occurring in Belarusian chironomids (Diptera: Chironomidae) subsequent to the Chernobyl nuclear disaster

“…These authors conceded that exposure to chronic doses of radiation may require several generations before genetic changes become sufficiently severe to be detected. Evidence suggests, on the other hand, that some insects may be capable of developing resistance to radiation through radiation‐induced gene modification (Change & Ducoff, 1989). At the Chernobyl site, for example, Zainullin et al .…”

“…These authors conceded that exposure to chronic doses of radiation may require several generations before genetic changes become suf®ciently severe to be detected. Evidence suggests, on the other hand, that some insects may be capable of developing resistance to radiation through radiation-induced gene modi®cation (Change & Ducoff, 1989). At the Chernobyl site, for example, Zainullin et al (1992) detected a signi-®cantly higher instance of sex-linked recessive lethal mutations in populations of fruit¯ies (Drosophila melanogaster) collected shortly after the accident compared with 3 years later.…”