A new species of Aspilota without a mesoscutal pit, A. murieli Peris-Felipo, sp. nov., is described and illustrated from Argentina. The genus Aspilota Foerster, 1863 is recorded from Argentina for the first time. A key to the Neotropical species of Aspilota is provided.

Alysiinae, Aspilota-group, diagnosis, identification key, parasitoid, South America

The genus Aspilota Foerster, 1863 is distinguished from other members of the subtribe Aspilotina by three key features: paraclypeal fovea extended to the inner eye margin, a closed distal brachial (first subdiscal) cell, and the presence of the vein cuqu1 (2-SR) in the fore wing (van Achterberg 1988; Peris-Felipo and Belokobylskij 2016; Peris-Felipo et al. 2025).

Aspilota species are primarily endoparasitoids of Diptera, Cyclorrhapha, with a focus on the family Phoridae. Records of hosts from other families such as Tephritidae, Anthomyiidae, or Sarcophagidae (Yu et al. 2016) are considered questionable and require further investigation (van Achterberg 1988). The genus comprises approximately 250 species described from nearly all zoogeographic regions.

Current knowledge of Aspilota in the Neotropical region is very limited. Prior to this study, only three species had been documented in this realm: Aspilota stigmalis Papp, 2012 from Colombia, and A. nemostigma Spinola, 1851 and A. pulchella Spinola, 1851 from Chile. Unfortunately, our study excludes the Chilean species due to two significant challenges. Firstly, we were unable to find the place of preservation of the type specimens for their study and revision. Secondly, the original descriptions of these species are extremely vague. These factors combined made it difficult to identify and select the necessary diagnostic characteristics needed for accurate identification in our research.

In this paper, the genus Aspilota is recorded for the first time from Argentina. Aspilota murieli sp. nov., characterized by the small size of the upper tooth of the mandible, is described and illustrated. Moreover, an identification key of the available Neotropical species is provided.

This study was conducted in the Rolling Pampas of Argentina (Fig. 1A), a region characterized by a temperate climate (Cfa/Cfb in the Köppen climate classification) (Soriano et al. 1991; Bianchi and Cravero 2010). The area experiences distinct seasonal variations, with warm to hot summers and cold winters. Average annual temperatures range from 13 °C to 17 °C, with summer highs exceeding 30 °C and winter lows occasionally dropping below freezing. The region is notable for its significant diurnal temperature fluctuations, particularly during summer. Annual precipitation in the Rolling Pampas varies between 800 and 1,200 mm, with the majority occurring in summer (Soriano et al. 1991; Bianchi and Cravero 2010).

Figure 1. 

A Farms location in Argentina B View of a wheatfield with Malaise traps installed.

The research encompassed 12 fields distributed in the Baradero, Solis, Teodelina and Vedia Districts from Argentina (Fig. 1A). The selected fields, with an average size of 77.25 ha (ranging from 40 to 213 ha), were managed under a rotational cropping system that alternated between corn, soybean, and wheat. Each field was equipped with 10 Malaise traps strategically placed at 10, 50, 100, and 150 m from the field edge (Fig. 1B). Two additional traps were set within 10 × 100 m strips of seminatural vegetation at the field margins. One of these strips was experimentally enhanced with a multifunctional floral margin to promote biodiversity, while the other served as an untreated control.

Trapping was conducted only when crops were present, with traps removed before harvest and reinstalled shortly after sowing. No data was collected during fallow periods. The study spanned two years (July 2022 to April 2024). In the first year (July 2022 to May 2023), traps operated continuously, with bi-monthly collections. The second year (August 2023 to April 2024) involved 15-day trapping periods each month.

Collected specimens were preserved in 70% alcohol and later identified to species. External morphology was examined using a ZEISS Discovery V8 stereomicroscope, with several specimens dissected and slide-mounted in Berlese medium for detailed analysis.

For the terminology of the morphological features, sculpture, and measurements, see Peris-Felipo et al. (2014); for wing venation nomenclature, see Peris-Felipo et al. (2014) and van Achterberg (1993). Following abbreviations have been used: POL (post-ocellar line, shortest distance between inner margins of lateral ocelli), OOL (ocular-ocellar line, shortest distance between outer margin of lateral ocellus and inner margin of eye), and OD (maximum diameter of ocellus). The species was identified by reviewing the description of the Neotropical Aspilota species (Spinola 1851; Fischer 1971; Papp 2012) due to the absence of a key to New World species.

For the molecular methods, the DNA from each sample was isolated using the Quick-DNA Microprep Plus kit (Zymo Research), specifically optimized for small tissue samples, strictly following the manufacturer’s instructions. The DNA was eluted in a final volume of 12 µL. DNA concentration was quantified using the Qubit High Sensitivity dsDNA Assay (Thermo Fisher Scientific). For PCR amplification, a 650-bp fragment from the 5′ region of CO1 was amplified using the LepF1 and LepR1 primers (Hebert et al. 2003, 2004; Park et al. 2010). Moreover, a fragment of around 666 bp of the 28S rRNA gene was amplified using D2-3665F and D3-4283R primers (Mardulyn and Whitfield 1999). PCRs were carried out in a final volume of 10 μL, containing 2.9 μL of template DNA, 0.5 μM of the primers, 5 μL of Supreme NZYTaq 2x Green Master Mix (NZYTech), CES 1X (Ralser et al. 2006), and ultrapure water up to 10 μL. The reaction mixture was incubated as follows: an initial denaturation step at 95 °C for 5 min, followed by 35 cycles of 95 °C for 30 s, 48.5 °C (LepF1 and LepR1) or 52.7 °C (D2-3665F and D3-4283R) for 60 s, 72 °C for 45 s, and a final extension step at 72 °C for 7 min. The PCR products were bi-directionally sequenced on an ABI 3730xl DNA Analyzer (Applied Biosystems, USA), with the same primers as those used in the PCR amplification. The amplification products were purified using magnetic beads (MagBind, Omega-Bio-tek) prior to sequencing.

The material was imaged using Keyence^® VHX-2000 Digital Microscope and post processed in Adobe Photoshop^®. The specimens are deposited in the Entomological collection of the Bernardino Rivadavia Natural Sciences Argentine Museum (Buenos Aires, Argentina; MACN-En), the Naturhistorisches Museum Basel (Basel, Switzerland; NMB), the Zoological Institute RAS (St Petersburg, Russia; ZISP), and the F.J. Peris-Felipo Private Entomological Collection (Basel, Switzerland; PFEC).

Species of the genus Aspilota are endoparasitoids of Diptera, laying their eggs in larvae and emerging from the host. They have been recorded across multiple zoogeographical regions worldwide. However, until now, knowledge of this group in the Neotropical region was restricted to Chile and Colombia (Yu et al. 2016). This study provides the first well-documented record of the genus Aspilota in Argentina and includes the description of Aspilota murieli sp. nov. The genetic data analysis confirms that this species is new to science, with its closest known relative being A. angusta Berry, 2007, previously recorded in Australia, Canada, and New Zealand. However, with a genetic similarity of only 94.92%, it is evident that A. murieli represents a newly identified species.

The diagnostic morphological traits of the Aspilota group align closely with the primary, well-established characteristics of the genus. These include the paraclypeal fovea extending to the inner eye margin, a closed distal brachial (first subdiscal) cell, and the presence of the vein cuqu1 (2-SR) in the forewing. These shared features facilitate genus identification.

The newly developed key for identifying the Neotropical Aspilota species, presented in this study, marks an important step toward advancing research on the biodiversity of this genus in the region.

The scarcity of data on this genus in the Neotropics may be attributed to the limited number of specialists focusing on parasitoid wasps and the general lack of entomological studies in the region. Future research on Argentine parasitoid wasps is strongly encouraged to gain a better understanding of their distribution and biology, as many of these species play a vital role in the biological control of fly pest populations.

We express our sincere gratitude to Seraina Klopfstein and Lucas Blattner from the Naturhistorisches Museum Basel (Switzerland) for their kindness and assistance during our work with the photosystem at the museum. We also appreciate the generosity and support of the owners, managers and technical advisors of “La Donosa” (MSU Agro), “Los Laureles” (Adecoagro), “La Casualidad” (CREA), “Los Montes” (CREA) and “Santa Inés” (CREA) for allowing us to carry out this study on their farms. Additionally, our heartfelt thanks go to Julio Muriel and Hernan Barbero for their invaluable contributions in making this project possible. Finally, we recognize to Neus Marí and AllGenetics & Biology SL (https://www.allgenetics.eu) for supporting with the DNA barcoding analyses.