Crocidosema aporema is a Neotropical Tortricidae moth that feeds on several wild and cultivated Fabaceae, and has a potential to cause economic damages. A new parasitoid wasp belonging to the genus Meteorus (Hymenoptera, Braconidae), which has been reared from C. aporema feeding on soybean in Brazil, is described and illustrated. A checklist of parasitoids previously recorded for C. aporema is provided.

biological control, Brazil, Epinotia, taxonomy

Crocidosema (=Epinotia) aporema (Walshingham) is a borer moth belonging to the family Tortricidae. It is widespread across Central and South America and can feed on several wild and cultivated Fabaceae, including alfalfa, broad bean, clover, common bean, lupin, melilot, peanut and soybean (Sanchez and Pereyra 2008). Crocidosema aporema is multivoltine and remains active year around, producing four to five generations (Sanchez et al. 1997).

This species can be of economic importance for several crops. Crocidosema aporema has received particular attention as a pest of soybean, due to the importance of this crop in South America, where this insect can become a relevant problem especially in colder regions such as Argentina and the south of Brazil (Sanchez et al. 1997; Hoffmann-Campo et al. 2000). It is also considered one of the few insects regularly causing damage to fodder leguminosae in Uruguay, especially due to the impact to seed production (Alzugaray 2004).

The control of C. aporema using agrochemicals can be a twofold problem, first due to its borer behavior, which reduces the effectiveness of contact pesticides, second because C. aporema is more likely to impact crop productivity when present during the flowering stage, thus the use of insecticides during this critical phase could also affect pollinators (Foerster et al. 1983; Alzugaray 2004). Furthermore, the conspicuous plant damages caused by C. aporema, even when occurring below the economic threshold, are known to precipitate the use of insecticides by farmers and consequently increase economic and ecological costs (Bueno and Sosa-Gómez 2021). Crocidosema aporema has also been recorded developing on Bt soybean expressing the cry1Ac gene, indicating the existence of populations that have acquired some level of resistance to this particular protein (Bueno and Sosa-Gómez 2021).

Meteorus Haliday is a genus of endoparasitoid wasps belonging to the family Braconidae, it has a cosmopolitan distribution and around 350 described species (Yu et al. 2016). The genus has been recorded parasitizing a wide range of Lepidotera larvae, including several of economic relevance (Shaw 1997). The biology of M. pulchricornis, for instance, has been extensively studied and the species has been considered a potential biocontrol agent for major insect pests such as Helicoverpa spp. and Spodoptera spp. (Maeto 2018).

Biological control agents acting naturally or under an integrated pest management system could help maintain a more sustainable and productive cropping (Bortolotto et al. 2015). In this context, the present work aims to contribute to this goal by describing a novel parasitoid of C. aporema belonging to the genus Meteorus.

The studied material is deposited at “Coleção Taxonômica do Departamento de Ecologia e Biologia Evolutiva da UFSCar” (DCBU), São Carlos, Brazil. Each examined specimen was given a unique collection catalog number (e.g. DCBU00000). Morphological terminology follows Sharkey and Wharton (1997), microsculpture terminology follows Harris (1979), measurements are taken as proposed by Aguirre et al. (2015). The description is based on the holotype and the variation found in paratypes is presented in parenthesis.

Images were obtained using a Leica DFC295 camera attached to a Leica M165C stereomicroscope and stacked with the Leica Application suite software v3.7.0. Pictures were later processed using Adobe Photoshop.

Meteorus lucianae sp. nov. is morphologically most similar to M. pseudodimidiatus Zitani and would be identified as such in the key to Neotropical Meteorus presented in Aguirre et al. (2015). Nevertheless the new species can be separated from M. pseudodimidiatus especially by the differences on head and eye shape. This can be most easily identified by the ratio between the malar space length and the mandible width, which is 0.40–0.62 × in M. lucianae sp. nov., while 0.80–1.50 × in M. pseudodimidiatus. The new species also resembles M. dimidiatus (Cresson) but can be recognized by having a complete occipital carina and a shorter ovipositor, with its ovipositor length being 1.93–2.53 × the first tergite length (while M. dimidiatus has an incomplete carina and ovipositor length 2.60–2.80 × first tergite length).

When compared to the Paleartic fauna, M. lucianae sp. nov. is most similar to M. tenellus Marshall. Most notably these species share the lack of dorsope, a narrow face, strongly twisted mandibles, frons with a median protuberance and ovipositor usually at least 2 times longer than the first tergite. Those shared morphological characteristics suggest that the new species could also belong to “Clade IIA” retrieved in the phylogenetic analysis presented in Stigenberg and Ronquist (2011). Similarly to the new species described here, M. tenellus and the closely related M. cinctellus (Spinola) have both been recorded utilizing Tortricidae hosts (Yu et al. 2016).

Currently the only known host association for the new species is the one here presented (C. aporema feeding on soybean). Nonetheless, it is noteworthy that several specimens studied were obtained from Malaise traps and were recorded in areas not typically associated with soybean production, including conservation areas. Is thus likely that in those areas the species is either utilizing C. aporema feeding in other Fabaceae or a different host species.

The genus Meteorus had not been recorded as a parasitoid of C. aporema, and in the Neotropics the use of Tortricidade as host is unusual in Meteorus (Aguirre et al. 2015). In contrast, several parasitoids from other taxonomic groups have been recorded using it as host, most belonging to the Hymenoptera superfamilies Chalcidoidea and Ichneumonoidea (Table 1).

The use of biological control agents such as parasitoids should be considered in managing pest insects as it represents a more sustainable alternative to the currently employed practices (Baker et al. 2020). Further investigation into this parasitoid autecology would be relevant to elucidate the factors affecting their natural occurrence. This in turn could be a relevant aid on conservation biological control programs, as well as providing new options for the integrated management of C. aporema.

We are grateful to Carolina Reigada Montoya, Manoel Martins Dias Filho and Odete Rocha for their comments on an earlier version of this manuscript. Financial support was provided by grant 2019/00858-1, São Paulo Research Foundation (FAPESP), and additional funding through the project INCT-HYMPAR,CNPq (Proc. 465562/2014-0) and FAPESP (Proc. 2014/50940-2).