Effect of temperature on the rate of pupal-adult development of the noctuid moth,Mamestra configurata Wlk.: evidence for differential effects on the initiation of development and subsequent metamorphic development

Summary Moths eclosed earlier from pupae of the bertha armyworm,Mamestra configurata, that were exposed briefly (1 to 5 days) to a warm temperature (15 or 20°C) at the beginning of postdiapause pupal-adult metamorphosis and then incubated at 10 or 12.5°C than from pupae incubated at 10 or 12.5°C throughout metamorphosis. The differences were greater than could be explained by the additional thermal units received at the higher temperature. Analyses of the times of peak concentrations of ecdysteroids (insect growth and development hormones) in metamorphosing pupae and of moth eclosion after exposure to various combinations of temperatures indicated that the warm termperature effect was not on the rate metamorphic development but on an earlier neuroendocrine process concerned with the initiation of development.The magnitude of the difference in eclosion time between pupac receiving a brief warm temperature trigger and the control suggests that the differential effect of temperature on the initiation of development and subsequent metamorphic development is of biological significance and should be considered in the construction of models of insect development under natural conditions.Contirbution No. 1188, Agriculture Canada Research Station, Winnipeg, Manitoba