Croissance, bilan d'energie et production d'eau metabolique chez la larve de Tineola bisselliella

Abstract

The keratophagous larva Tineola bisselliella develops better in a dry than in a wet environment at the constant temperature of 20 °C. At 95% relative humidity (RH), mortality is higher than 80% and the larval life lasts up to 341 days. At 5% RH, mortality reaches only 30% and the larval life lasts only 216 days. The study of utilization of the energy contained in 3680 μg of food (mukrat hair) at 95% RH and then at 5% RH shows the physiological reactions of the larva when the RH is modified. At 5% RH, the larva ingest the 3680 μg of food in 17 days while they ingest the same amount in 10 days at 5% RH. For the same quantity of ingested energy, the energetic value lost by respiration and silk secretion are more important at 95% RH than at 5% RH. In a very wet environment, the energy lost in the feces is reduced. At 5% RH, the production of body tissue and the storage of the ingested energy are twice as high as those at 95% RG, in spite of a loss of water which may exceed 4 μg/h. The production of metabolic water allows the larva to keep constant its quantity of body water and does not prevent the storage of lipidic substances. The weight of metabolic water produced at 5% RH is evaluated at 33% of the weight of the ingested food.