Structure of the food web including the endangered lycaenid butterfly Shijimiaeoides divinus asonis (Lepidoptera: Lycaenidae)

摘要

The structure of the food web including the endangered lycaenid butterfly Shijimiaeoides divinus asonis (Matsumura)was analyzed to identify species contributing most to maintaining the equilibrium of the food web. Twenty-seven species belonging to 17 families fed on Sophora flavescens Aiton, the host-plant of S. divinus asonis: 15 species were leaf and stem feeders, seven (including S. divinus asonis)fed on flower buds, four were flower feeders and one fed on the seeds of So. flavescens. Of these 27 species, four were omnivores. The natural enemies of S. divinus asonis comprised six insect species, 11 spider species and one entomopathogenic fungus species, including six new predator records. The linkage density, total number of trophic links, connectance, average chain length and predator-prey ratio were 1.617, 97, 0.0548, 2.267 and 0.694, respectively. Exclusion of any of the 15 species with four or more trophic links reduced the connectance of the food web. These 15 species included facultative mutualistic attendant ants and predators of S. divinus asonis, herbivores to So. flavescens, an omnivore feeding on S. divinus asonis and So. flavescens, and prey insects. Therefore, future studies should monitor these 15 species.