Parasitoids, predators, or scavengers? On the nature of flesh fly (Diptera: Sarcophagidae: Sarcophaginae) interactions with eusocial wasps (Hymenoptera: Vespidae) in light of new findings in Brazil

Abstract Nests of eusocial wasps (Hymenoptera: Vespidae) are dynamic ecosystems that host a diverse array of organisms with varied ecological roles. Among the most common associates are true flies (Diptera), whose larvae act as sarcosaprophages, predators, or parasitoids. While the interactions of many dipterans with eusocial wasps are known, the precise nature of relationships between Sarcophaginae flesh flies (Sarcophagidae) and eusocial wasps has been a subject of debate, with many authors interpreting them as parasitoids or predators of the wasp brood. We re-evaluated the evidence for Sarcophaginae-Vespidae interactions in light of a new record of Sarcophaga ( Neobellieria ) polistensis Hall, 1933 in a nest of Polistes simillimus Zikán, 1951 from Brazil. The new record is described, including illustrations of males and females of S. ( N. ) polistensis , with notes on the taxonomy, distribution, and diagnostic characters of the species. Furthermore, we present a comprehensive revision of all known Sarcophaginae-Vespidae records, providing a new perspective on the classification and evolution of the feeding habits of these flies. Based on our observations and a comprehensive review of the literature, we argue that Sarcophaginae-Vespidae interactions are best described as being sarcosaprophagous. While predation cannot be entirely discarded in the absence of detailed observations, there is currently no evidence to support parasitoidism in Sarcophaginae-Vespidae interactions.