Ecology and behavioral patterns of Luciola cruciate in a restored forest in a chemical plant

Efforts to restore firefly populations are ongoing; these populations have been declining due to the development of cities and industries. The first step in restoration is the development of a breeding system that can accommodate approximately 5000 hatched larvae of Luciola cruciate, an aquatic firefly species, until they reach the last instar larval stage. The bred larvae are released into a river in a restored forest in a chemical plant, where they can breed naturally. Firefly-viewing events are organized so that people can experience the pleasure of watching fireflies. Such events can be successful if the peak flight season of fireflies can be predicted accurately. There is scope to improve the methods used for flight season prediction, which have impaired prediction accuracy owing to the variability of regional characteristics. In this study, data on fireflies and meteorological data accumulated for the restored forest over 11 years were analyzed and the peak flight days of L. cruciate adults and climbing by L. cruciate larvae were discussed. The new regression equation-based method proposed in this study, which used the breeding temperature and minimum humidity, can estimate the peak flight date of adult fireflies better than the conventional method based on the effective cumulative temperature. As part of the ecology of fireflies, statistical analysis on climbing by larvae revealed that minimum air temperature and cumulative precipitation were significant predictors of climbing and that climbing occurred on a rainy night with a minimum air temperature of >= 10 degrees C.