Pupal diapause in Hypocosmia pyrochroma (Lepidoptera: Pyralidae), a biological control agent for Dolichandra unguis-cati (Bignoniaceae)

Abstract

Cats claw creeper leaf-tying moth Hypocosmia pyrochroma (Lepidoptera: Pyralidae) enter pupal diapause in the soil from middle of autumn (April), in response to declining photoperiod. Proportion of larvae entering pupal diapause increased with decreasing Daily Solar Radiation (DSR), and all larvae completing development in winter under low DSR entered pupal diapause. Under natural photoperiod, adults emerged from pupal diapause, from late spring (October) to middle of summer (January), with peak adult emergence in late spring (November) and early summer (December). Pupae did not undergo diapause when the entire development (eggs and all larval instars) occurred under prolonged photoperiod (14 L:10D). However, it was not possible to terminate the pupal diapause either by prolonging photoperiod or by increasing the temperate regimes. Based on larval incidence in the field it is proposed that H. pyrochroma is a bivoltine species with overlapping generations.