A sweet bite? The first record of Phenax variegata (Hemiptera: Fulgoridae) predation by Callithrix kuhlii (Primates: Callitrichidae)

Abstract Understanding the dietary habits of Neotropical primates is essential for elucidating trophic interactions and energy flow within tropical ecosystems. In this study, we report the first documented case of predation of the fulgorid planthopper Phenax variegata (Hemiptera: Fulgoridae) by Wied’s marmoset, Callithrix kuhlii (Primates: Callitrichidae), a small-bodied primate endemic to the Atlantic Forest of Brazil. The observation occurred during primate behavioral monitoring in a heterogeneous landscape composed of native forest, agroforestry systems (cabrucas), and mangrove fragments in Ilhéus, Bahia. A group of C. kuhlii was observed foraging in the canopy when one individual captured and consumed an unidentified insect. The wings were deliberately detached by the marmoset and fell to the ground. One forewing was subsequently recovered and identified in the laboratory as belonging to P. variegata . This is the first record of a primate preying upon a species of Fulgoridae, a group of sap-feeding hemipterans with important ecological roles in forest environments. Although insectivory is known in Callithrix , species-level records of insect prey remain scarce, particularly for C. kuhlii , largely due to observational limitations. This observation documents a previously unreported trophic interaction and raises the possibility that fulgorids may be included among the arthropod prey consumed by C. kuhlii . Additional observations are required to determine the frequency and nutritional significance of this interaction. Opportunistic records such as this can provide useful baseline information for future studies of primate feeding behavior and canopy-level trophic interactions.