New species of fly intrigues scientists by living among up to 1 million wasps Rodrigo de Vilhena Perez Dios A new species of fly described by researchers at the Museum of Zoology at the University of São Paulo (USP) drew attention due to an unusual habit: it lives associated with the nests of wasps of the species Agelaia vicina, known for forming the largest colonies of social wasps in the world, with up to 1 million individuals. ? Also follow Terra da Gente on Instagram Named Brevialata deceptrix, the fly was found in nests collected in Cajuru (SP). The researchers observed that it can live with the wasps without being attacked, even inside the nests. Despite the discovery, this behavior is still a mystery. Researchers do not know why the wasps tolerate their presence, whether the fly spends its entire life cycle inside the nest or which organism serves as host for its larvae. For Rodrigo de Vilhena Perez Dios, postdoctoral researcher at the USP Zoology Museum and main author of the study, the description of the species is the first step in unraveling these questions. "According to the reports of the researchers who collected them at the time, they entered and left the nests without being attacked. Now that the species is described, and the scientific community is aware of its existence, we need to find nests of this species of wasps again and study these flies in more detail", he states. See more news from Terra da Gente, on g1: WARM UP: Why are penguins changing their breeding calendar in Antarctica? DISGUISE: How this beetle can 'deceive' an entire colony of termites 'GHOST' PRIMATE: Unpublished photos show newborn parauacu baby A 30-year-old mystery Although the species has only been described now, the first specimens were collected in 1993. At the time, researchers found eight individuals associated with Agelaia vicina nests and deposited them in the entomological collection of the USP Museum of Zoology. Without identification, the material remained stored for decades. The first steps towards describing the species only took place years later, during Rodrigo's post-doctorate. A graduate student took a specimen to the researcher and raised the question of whether it was a deformation or a different species. From there, Rodrigo revisited the museum collection, where he found the specimens collected in the 1990s and confirmed that it was a species that had not yet been described. "These flies came to the museum's collection in the 90s, but they remained in the collection as unidentified since then, until I found them. With a larger series of specimens and by contacting the researchers who collected them, who told me about their behavior, it was possible to describe this very curious species", he reports. New species of fly intrigues scientists by living among up to 1 million wasps Rodrigo de Vilhena Perez Dios Parasitoid fly The main information revealed by the description of the species concerns its parasitic habits. The family to which it belongs, Tachinidae, is made up mainly of parasitoid species of other insects and arthropods and comprises more than 9 thousand species. Therefore, the researchers consider it safe to say that the new fly also exhibits this behavior, although it has not yet been directly confirmed. In these insects, the larvae develop inside another organism and, at the end of development, lead the host to death. The main hypothesis raised by the researcher is that flies parasitize wasp larvae. However, they can also use another insect that lives in these large nests as a host. According to Rodrigo, colonies of social insects usually house several associated organisms, which expands the possibilities. The fly measures about 0.6 centimeters and has reduced wings, fewer body bristles and more robust legs. The wasps with which it associates reach just over 1 centimeter. According to Rodrigo, it is not yet possible to say exactly what the function of these adaptations is, but they may be related to life inside the nests. “The robust body and legs and the absence of bristles possibly encourage flies to enter and walk around the nest and tighter spaces, or even cling to some wasps” The reduction of wings is a characteristic observed in several insects with parasitic habits. Protection and development Regardless of their host, living close to thousands — or even 1 million — of wasps can bring important advantages to flies. According to Rodrigo, the main one is protection against predators. “Being close to the wasps certainly provides some type of protection, as other insects and predators rarely come close to this large number of wasps”, he explains. This type of association, however, still needs to be studied in the field so that scientists understand how the fly manages to remain in the nest without arousing the wasps' aggression. Another mystery involves the females of the species, which have not yet been found. To date, only males have been collected. Even so, researchers believe that females live inside nests, based on the males' behavior of entering and leaving colonies. "In general, adult parasitoid fly males have the main objective of finding females and managing to mate. Therefore, these females are most likely inside the nests" Finding these females and observing the complete life cycle of the species are among the researchers' next challenges. More than three decades after its collection, the small fly continues to be surrounded by questions — and may reveal new forms of interaction between insects that still go unnoticed by science. *Under the supervision of Rodrigo Peronti. 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