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EXPERIMENTS ON THE RESISTANCE OF THE FLOUR MOTH (EPHESTIA KVHNIELLA ZELL.) TO ABNORMALLY HIGH TEMPERATURES
Author(s) -
MANSBRIDGE G. H.
Publication year - 1936
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1936.tb06128.x
Subject(s) - biology , larva , pupa , horticulture , zoology , botany
SUMMARY Experiments are described on the resistance to heat of E. kühniella in all its stages. With eggs exposed to 45 o C. (113 o F.) and 47 o C. (116‐5 o F.) it is seen that:1 One‐day‐old eggs are more resistant than older ones. 2 Eggs are more resistant to heat at low than at high humidities. 3 Eggs appear to be able to cool themselves at low humidities in a high temperature by the evaporation of water. 4 After heating, eggs can regain water they have lost if they are kept in a moist atmosphere. 5 After heating at low humidities, there is a bigger survival if the eggs are kept in a moist atmosphere than if they are kept in a dry atmosphere. 6 There is great variation in stock direct from a mill. Eggs from different pairs of moths may have widely different degrees of resistance. 7 Stock which has been inbred in the insectaries for twelve generations, shows less variation in resistance than stock direct from a mill.Larvae are much less resistant than eggs. Newly hatched larvae and all larvae until they are full grown have about the same resistance. Last‐stage larvae are far more resistant than other larvae. Pupae are more resistant than feeding larvae. Adults are the most susceptible stage to heat. At low humidities the females are more resistant than the males. Experiments on all stages in undisturbed cultures show that a temperature of 45–46 o C, maintained for 3 hours, kills all stages. This work was carried out under the direction of Prof. J. W. Munro, to whom I am grateful for his constant encouragement. I have to thank Mr G. V. B. Herford for his help in devising and constructing the apparatus and reading through the typescript, and I am also indebted to Dr 0. W. Richards for his helpful advice on many occasions, and to Mrs Richards who kindly supplied me with a highly inbred strain of E. kühniella. Lastly I thank Dr G. Fraenkel for many important suggestions, especially those contained in the discussion.