Larval Feeding Habits of Five Firefly Species Across Aquatic, Semi-Aquatic, and Terrestrial Lineages

While adult fireflies are terrestrial, their larvae inhabit various habitat types, and a lack of comprehensive research on the feeding habits of these larvae across different habitats has greatly impeded the development of artificial diets. Here, we tested 14 types of foods, primarily covering gastropods, vertebrates, and fruit, to survey feed for aquatic (<i>Aquatica leii</i> and <i>Sclerotia substriata</i>), semi-aquatic (<i>Pygoluciola qingyu</i> and <i>Pygoluciola</i> sp.), and terrestrial (<i>Pyrocoelia analis</i>) fireflies. The results show that <i>A. leii</i>, <i>S. substriata</i>, <i>P. qingyu</i>, <i>Pygoluciola</i> sp., and <i>P. analis</i> fed on 12, 6, 10, 10, and 7 different foods, respectively, showing an obvious difference in feeding range among various inhabit types of fireflies. Aquatic lineages preferred to consume freshwater snails, followed by pork meat and land slugs, while semi-aquatic fireflies favored freshwater snails, followed by fish and shrimp. Favorite foods were thus freshwater snails such as <i>Cipangopaludina chinensis</i> for both aquatic and semi-aquatic fireflies, but feeding preference differed for second favorite foods (e.g., pork vs. fish meat). Terrestrial <i>Pyrocoelia analis</i> showed different feeding preferences compared withthe other two habitat lineages, with terrestrial snails and slugs as their favorite foods, followed by freshwater snails, such as <i>C. chinensis</i>. These findings not only uncovered larval feeding habits of fireflies across various inhabit types but also indicated that readily available and affordable <i>C. chinensis</i> products can serve as wild snail alternatives in the artificial feeding of fireflies. This study is the first to explore the feeding habits of firefly species inhabiting water and land habitat types, adding to the understanding of the feeding characteristics of fireflies.