Larval respiration system and evolution in aquatic fireflies (Coleoptera: Lampyridae: Luciolinae)

Aquatic larvae of the firefly Luciola substriataGorham are of two different morphological types.First and second instar larvae have bristle-like structures on the lateral margins of the abdomen,which are confirmed as gills. First to second instar larvae use both gills and tracheae to respire. Third to sixth instar larvae lack lateral abdominal gills and depend on a well-developed metapneustic tracheal respiration system. Four other species with very similar aquatic larvae, viz.Luciola leii Fu et Ballantyne, L. ficta Olivier, L. lateralis Motsch., and L.cruciata Motsch., have gill-spiracle compound structures along the sides of the abdomen. The possibility that aquatic fireflies evolved from terrestriallampyrids, and that Luciola substriata may have secondarily returned to water, is explored.