Abstract
The seasonal and daily occurrence patterns of two adult fireflies, Luciola kuroiwae and Curtos okinawanus, were studied on the main island of Okinawa in 2013 and 2014. L. kuroiwae showed a single peak of seasonal adult occurrence from late April to mid May. Two peaks of adult occurrence were recognized in C. okinawanus, in May-June and September-October. Adults of L. kuroiwae and C. okinawanus were active (i.e., flashing) only immediately after sunset at most study sites. However, L. kuroiwae was observed to be active at midnight at one study site, only in 2013. This site was artificially lit until midnight, and the fireflies started to flash soon after the light was turned off. In 2014, when the light was always off, L. kuroiwae at the same site was active soon after sunset, similar to other sites. These results suggest that midnight flashing of L. kuroiwae in 2013 might have been caused by artificial lighting lasting until midnight.
