Temperature-effect as a factor for the pupation of anthrenus verbasci (coleoptera, dermestidae)

Abstract

1) Anthrenus verbasci has one generation a year ; pupal, adult and egg stages fall on April, May and June, and the larval stage continues for nearly 10 months. 2) When the larvae fed under the natural condition are transferred to 25°C by December, there occurs no pupation. When the transfer is carried out from February In the following year, all larvae pupate within several days. 3) The larvae fed continuously at 30°C hardly pupate, and continue to live at least for 1.5 years. At 25∼15°C, pupation is observed from 8 months after hatching, the shortest duration being found in 20°C. 4) The larvae hatched in May were transferred to 5∼20°C in September, kept for 1∼5 months and returned again to 25°C. The larvae kept in 5°C did not pupate ; pupation was observed with those treated for longer than 3 months (inclusive) in 10∼20°C. The rate of pupation is nearly 100 % with the treatment of 4 months in 15∼20°C. 5) The effect of temperature is the highest for 15°and 20°C, decreased in higherand lower range, and nearly null in 30°and 5°C. 6) It seems to be concluded that the larvae have a kind of block for pupation, which is similar to diapause, and that for passing over the block, temperatures in a specific range as shown in 5) are effective. © 1951, The Japanese Society of Sericultural Science. All rights reserved.