Weight loss and mortality of three life stages of Tribolium castaneum (Herbst) when exposed to four modified atmospheres

Larvae, pupae, and adults of Tribolium castaneum (Herbst) were exposed to atmospheres containing high nitrogen (N₂) or carbon dioxide (CO₂) concentrations at about 50% r.h. and 27°C for periods up to 72 hr. Overall, 99% N₂ caused greater mortality in adults than did 58% CO₂ while 58% CO₂ was more effective against pupae. The difference in mortality to larvae exposed to the two atmospheres was not significant, though 99% N₂ produced greater mortalities by 48 hr. Also, the differences in mortality for larvae and pupae exposed to atmospheres of 58% CO₂ and 97% CO₂ were not significant though 97% CO₂ caused a significantly greater mortality in adults than did 58% CO₂. Both mortality and weight loss of all life stages tested were small when the insects were exposed to an atmosphere of 97% N₂, but weight loss was generally small and mortality was large for those insects exposed to 97% CO₂.When overall weight loss was compared for those insects exposed to 58% CO₂ and 99% N₂, larval weight loss was greater for those exposed to the CO₂ atmosphere; pupal weight loss was not significantly different between the two atmospheres; adult weight loss was greater for those exposed to the N₂ atmosphere.