Life Cycle and Floral herbivory of the weevil Stethobaroides scutellatus Casey, 1922 (Coleoptera: Curculionidae) on a widespread Neotropical orchid

Orchid collections worldwide are increasingly threatened by specialist herbivores inadvertently transported through plant trade, yet basic biological information on these species is often lacking. We describe the natural history of the baridine weevil Stethobaroides scutellatus Casey, 1922 (Coleoptera: Curculionidae) infesting cultivated and naturally occurring Catasetum orchids in Brazil (Southeast, North, and Central-West regions). By dissecting damaged flowers and rearing adults from inflorescences, we document larval feeding within perianth, ovary, and pedicel tissues. Larvae exit flowers 7–10 days after hatching from eggs, pupate in soil, and emerge as adults 18–30 days later (total development approximately 25–40 days). The host range is expanded to multiple Catasetum species and two artificial hybrids (Catasetum Grigorio Leao and Clowesetum Leprechaun). In male flowers, infestation was frequent: 52% (54/104) in Catasetum fimbriatum and 100% (8/8) in Catasetum macrocarpum; from Catasetum fimbriatum we recovered 107 larvae, mainly from the labellum and column. Among dissected female flowers (n = 53), 3.8% contained live larvae, while additional flowers showed feeding scars. We propose practical management measures: prompt removal and destruction of damaged flowers, post-outbreak substrate replacement or sterilization, and quarantine of newly acquired plants to interrupt development and reduce spread.