New records of fern-spore feeding moths and notes on their biology from Guangdong Province, China

Fern spore‑feeding represents a specialized but understudied plant–insect interaction. Despite the growing number of taxonomic and life-history studies on spore-feeding insects, available research remains geographically biased toward East Asia, particularly Japan, South Korea, and Taiwan of China. In this study, we documented four stathmopodid moth species (Lepidoptera: Stathmopodidae: Cuprininae) associated with fern sori in Guangdong Province, southern China: Calicotis exclamationis , Thylacosceles cuneiformis , Thylacosceloides vaginivella , and Trigonoda fuscimaculata . Three of these species represent new records for mainland China, and all four were recorded on new host plants. Through field surveys and laboratory rearing, we confirmed larval host associations and documented life-history traits, including feeding behavior, shelter construction, and pupation. Larvae construct three distinct shelter types, patch-like shelters, strip-shaped shelters, and tunnels excavated within sporangia, which likely function to regulate microclimate, reduce exposure, and enhance crypsis. The relatively long activity period of these moths in subtropical Guangdong suggests that prolonged spore availability shapes their phenology. Host-use patterns varied among species, ranging from host-specific to relatively broad host ranges. These findings expand the known geographic distribution and host associations of fern spore-feeding moths and provide insights into the ecological and evolutionary constraints shaping this specialized niche.