2013 Volume 18 Issue 1 Pages 91-99
We aimed to evaluate the habitat factors affecting the aquatic fireflies Luciola cruciata and L. lateralis at 17 locations in paddy fields on valley-bottoms in northeast Chiba Prefecture from June to September, 2010. Paddy fields where aquatic fireflies were present had more abundant Japanese freshwater snails Semisulcospira libertine and a looser cliff gradient of the irrigation canal than did those from which aquatic fireflies were absent. Multiple regression analysis revealed that depth of sediment and dissolved oxygen (DO) had positive significant effects on the abundance of Japanese freshwater snails. The results of logistic analysis showed that DO and the cliff gradient of irrigation canals could be adopted as valid variables to predict the presence of aquatic fireflies. The improvement of canals through lowered canal weirs to provide dissolved oxygen via aeration drainage, and looser cliff gradients made of soft soil to enable last instar larvae to climb the cliff and subsequently conceal themselves underground, is considered valid management action for the conservation of habitats of larval aquatic fireflies.
