Revising spider egg-predating fly records (Diptera: Sarcophagidae): new insights on prey, taxonomy, and distribution of Sarcophaga (Mehria) lorosa Hall in Southern South America

Abstract

Flesh flies (Diptera: Sarcophagidae) exhibit a wide range of feeding habits including necrophagy, coprophagy, kleptoparasitism, parasitism, and predation. Among them, species of Sarcophaga Meigen belonging to the subgenera Baranovisca Lopes and Mehria Enderlein are specialized predators of spider eggs. These flies hover around the spider webs and lay their larvae on the spider egg sac. While progress has been made on the taxonomy of Baranovisca and Mehria in recent decades, our knowledge about their biology, prey selection, and distribution remains limited, restricting our understanding of the evolutionary dynamics of Sarcophagidae-Araneae interactions. Here, we describe and illustrate the first record of S. (M.) lorosa Hall preying on egg sacs of Metepeira galatheae (Thorell) (Araneae: Araneidae) in Chile. The taxonomy of S. (M.) lorosa is revised, with two new junior synonyms proposed: Weyrauchimyia ruficauda Lopes and Tibana, syn. nov., and Arachnidomyia travassosi Tibana and Mello, syn. nov. Furthermore, we present an annotated catalog that comprehensively reviews the existing records of spider egg-predating Sarcophagidae, and provide an overview of the evolution of Sarcophagidae-Araneae interactions. Our catalog includes information on at least four species of Baranovisca and 10 species of Mehria that have been documented as preying on eggs from species of various spider families, such as Araneidae, Cheiracanthiidae, Clubionidae, Philodromidae, Salticidae, and Tetragnathidae. These records cover all biogeographical regions except the Afrotropical. Our results contribute to enhancing our understanding of Sarcophagidae-Araneae interactions, shedding light on the evolution of these interactions.