#ZooKeys ZooKeys 1250: 293-314 (2025) DOI: 10.3897/zookeys.1250.151740 Research Article Two new species of Szelenyiopria Fabritius (Hymenoptera, Diapriidae), larval koinobiont endoparasitoids of the leaf-cutter ant Acromyrmex coronatus (Fabricius) (Hymenoptera, Formicidae), from Panama Gabriel Arauz'?, Vasilisa Chemyreva*®, Tomas Rios*®, Dumas Galvez2>*’®, Roberto A. Cambra®®, Enrique Medianero2®, William T. Wcislo’, Hermogenes Fernandez-Marin'® on Do BP WO NYP — Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Cientificas, Ciudad del Saber, Ciudad de Panama, 0843-01103, Panama Programa Centroamericano de Maestria en Entomologia, Universidad de Panama, Ciudad de Panama, Panama Zoological Institute, Russian Academy of Sciences, 1 Universitetskaya Emb., St Petersburg 199034, Russia Museo de Peces y Agua Dulce (MUPADI), Universidad Aut6noma de Chiriqui, Chiriqui, Panama Coiba Scientific Station, City of Knowledge, Calle Gustavo Lara, Bld. 145B, Clayton, 0843-01853, Panama Sistema Nacional de Investigacion, Panama, Panama Smithsonian Tropical Research Institute, Apartado 0843, Balboa, Ancon, Panama Museo de Invertebrados G. B. Fairchild, Escuela de Biologia, Universidad de Panamd, Panama, Panama Corresponding author: Hermégenes Ferndndez-Marin (hfernandez@indicasat.org.pa) OPEN Qaccess Academic editor: Norman Johnson Received: 28 February 2025 Accepted: 21 July 2025 Published: 1 September 2025 ZooBank: https://Zoobank.org/ CE0/276D-0B67-455C-8AB6- E3A8024738D8 Citation: Arauz G, Chemyreva V, Rios T, Galvez D, Cambra RA, Medianero E, Wcislo WT, Fernandez-Marin H (2025) Two new species of Szelenyiopria Fabritius (Hymenoptera, Diapriidae), larval koinobiont endoparasitoids of the leaf-cutter ant Acromyrmex coronatus (Fabricius) (Hymenoptera, Formicidae), from Panama. ZooKeys 1250: 293-314. https://doi. org/10.3897/zookeys.1250.151740 Copyright: This is an open access article distributed under the terms of the CCO Public Domain Dedication. Abstract Leaf-cutter ant nests attract a wide variety of guests and parasites due to considerable food resources, substrate and shelter available within nests. Limited information is known about their taxonomy, bionomics, and natural history, including interactions with the ants, and degree of host specificity of these symbionts. Here we describe two new species of Szelenyiopria Fabritius, 1974 (Diapriidae, Diapriinae, Diapriini) wasps which are koinobiont endoparasitoids of the larvae of a leaf-cutter ant, Acromyrmex coronatus (Fabricius, 1804) (Myrmicinae, Attini) in Chiriqui, Panama. For both new Szelenyiopria species, S. fortunensis Arauz & Fernandez-Marin, sp. nov. and S. chiriquiensis Arauz & Fernandez-Marin, sp. nov., we provide information on parasite—host interactions. The most abundant and frequent parasitoid type was solitary, while gregarious parasitoidism, where two or more wasps emerged from a single ant larva, was associated with certain times of the year. We provide an updated key to females of all species of Szelenyiopria, their geographic distribution, and host-parasite interactions. Szelenyiopria previously had been identified as parasitoids of several ant genera including some Acromyrmex species, but our data indicate that some species of Szelenyiopria may be specialized on A. coronatus ants. Rates of parasitism suggest that the wasps have a negative effect on colonies and populations of the ants. Key words: Attini, endoparasitoid, fungus-growing ants, larvae, parasitism Introduction Ants are distributed nearly worldwide in diverse terrestrial ecosystems (Hdlldobler and Wilson 1990; Savage et al. 2014). Their nests contain sub- stantial amounts of food resources and individuals, which attract numerous 293 Gabriel Arauz et al.: Szelenyiopria wasps endoparasitoids of Acromyrmex coronatus ant natural enemies and cohabitants with different life strategies (H6lldobler and Wilson 1990; Hughes et al. 2002; Quevillon 2018). Among these, some parasitoid insects complete their life cycle within the nests of various ant species (Eggleton and Belshaw 1992; Lachaud and Pérez-Lachaud 2012). Parasitoids can enter the colony either directly, or by being transported by ants that are returning to the nest after foraging or other tasks (Wojcik 1989; De Bekker et al. 2018). Inside the colony, they deploy various strategies to evade the defensive responses of their hosts, including morphological and behavioral adaptations (Mclver and Stonedahl 1993), or by mimicking the hydrocarbon chemical profiles of the host (Wojcik 1989; De Bekker et al. 2018; Neupert et al. 2018). A little-known taxon of parasitoids that attacks ants is Diapriidae (Hy- menoptera, Diaprioidea). They are koinobiont endoparasitoid wasps: the female injects an egg into the larva of the host ant where the wasp larva grows and feeds on internal tissues without consuming the cuticle, which becomes a protective cover for the parasitoid larva, analogous to a cocoon (Fernandez-Marin et al. 2006; Loiacono et al. 2013). According to Paz et al. (2024), at least 30 genera of Diapriidae wasps are associated with ants primarily fungus-growing ants (Formicidae, Myrmicinae, Attini), including Apterostigma Mayr, Acromyrmex Mayr, Cyphomyrmex Mayr, and Mycetomo- ellerius Solomon, Rabeling, Sosa-Calvo & Schultz (formerly Trachymyrmex) (Fernandez-Marin et al. 2006; Pérez-Ortega et al. 2010; Loiacono et al. 2013; Mattoso et al. 2021). The presence of these wasps in ant nests negatively affects ant colonies, resulting in considerable effect on their demographics, since wasps can parasitize up to 100% of the ant larvae (Fernandez-Marin et al. 2006; Rodrigues et al. 2015). Within Diapriidae, the genus Szelenyiopria Fabritius has 13 described spe- cies. Four species and two morphotypes are associated with ant species be- longing to Attini and Ecitonini, including Acromyrmex (Loiacono 1987, 2000, 2013; Mattoso et al. 2021), Mycetomoellerius (Trachymyrmex) (Pérez-Ortega et al. 2010), Eciton Latreille (Ferriére 1929), and Neivamyrmex Borgmeier (Ferriére 1929). The host remains unknown for nine of the species described. In nearly all cases, very little is known about the biological interactions between Szeleny- iopria and their hosts and its geographical distribution. The aim of this work is (i) to describe two new species of Szelenyiopria, which are larval endoparasitoids of the leaf-cutter ant Acromyrmex coronatus in Panama; and (ii) to provide information about the biology of the parasitism and expand the knowledge of parasite-host interactions between Szelenyio- pria wasps and fungus-growing ants. Materials and methods Ant hosts Acromyrmex is a genus of leaf-cutting ants comprised of 42 species, and A. coronatus has one of the wider geographical distributions. Acromyrmex coronatus has a Neotropical distribution inhabiting cloud and humid forests between 600 and 2,000 m of altitude (J. Longino in AntWeb 2024) from Mex- ico to Argentina, and the Atlantic Forest region of Brazil at sea level. 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