Photoperiodic control of larval development and pupation timing in the carpet beetle Anthrenus nipponensis (Coleoptera: Dermestidae)

Abstract

The larvae of carpet beetles of the genus Anthrenus (Coleoptera: Dermestidae) are indoor pests that feed on dry animal matter. The varied carpet beetle, Anthrenus verbasci, which pupates in spring, controls the larval period using a circannual clock responding to changes in photoperiod. However, there is a lack of research on the mechanism controlling the larval period of Anthrenus beetles that pupate in autumn. The effect of photoperiod on larval development and pupation timing was examined at 20°C in Anthrenus nipponensis Kalík & Ohbayashi that pupates in autumn. The larvae developed well under constant long days of light/dark (LD) 16:8 h, and pupation occurred approximately 29 weeks after hatching. Under constant short days of LD 12:12 h, larval development was strongly suppressed, and only a few individuals were able to pupate. The median larval weight at 26 weeks after hatching under LD 12:12 h was 0.22 mg, 3.7% of that under LD 16:8 h (5.96 mg). Because of this suppression of larval development, it was inconclusive whether the larval period of A. nipponensis is controlled by a circannual clock. In addition, the transfer from LD 16:8 h to LD 12:12 h at 15 weeks after hatching resulted in pupation 9 weeks earlier than that at constant LD 16:8 h. It is probable that in the field, young larvae develop by exposure to long days in early summer and mature larvae exposed to decreasing daylength in late summer achieve synchronized pupation in autumn.