EFFECTS OF TEMPERATURE AND LIGHT INTENSITY ON NOCTURNAL ACTIVITY PATTERNS OF THE NORTHERN JUNE BEETLE, PHYLLOPHAGA FUSCA, AND THE COMMON JUNE BEETLE, P. ANXIA (COLEOPTERA: SCARABAEIDAE)

Abstract

AbstractIn western Quebec, first flight of overwintered adults of the northern June beetle, Phyllophaga fusca (Froelich), and the common June beetle, P. anxia (Le Conte), occurred in mid-May with the accumulation of about 156 degree-days above 5 °C beginning 1 April. When soil temperature was 10 °C or higher, flight started 12–45 min after sunset, apparently in response to an endogenous rhythm that was triggered by low light intensity within the range 1.0 to 96.9 lux; high soil temperature induced early flight. Early in the flight season, duration of flight was 10–46 min and was inversely related to time of flight initiation. In early June, the flight began in darkness and was associated with peak oviposition and ageing; it lasted 20–35 min and was directed into the trees or to oviposition sites within a field.Males were attracted to light during a pre-copulatory flight which lasted more than 1 h until maximum coupling occurred near 2230 h; beetles remained in copula for 3 h or more. Morning flight directly back to the soil was triggered by light intensity increasing to about 1.0 lux.