The family Evaniidae comprises 32 genera and about 600 described species (Deans et al. 2017), and are popularly known as ensign wasps, nightshade wasps, or hatchet wasps in English, or “vespas-bandeira” and “vespas-machadinha” in Portuguese. These parasitic wasps are recognized by the insertion of the metasoma in the upper part of the mesosoma (Huben 2006; Deans 2011). Although the available information on the biology of evaniids indicates that they are solitary endoparasitoids of cockroach egg capsules, the hosts and oviposition behavior for most evaniid species are still unknown (Deans 2011), especially for species from tropical regions (Huben 2006). Among the evaniid taxa, the genus Semaeomyia Bradley 1908 (Hymenoptera: Evaniidae) is distributed over the Neotropical region and consists of 38 described species. There is no available information regarding the hosts of these species (Huben 2006; Deans 2011; Deans et al. 2017).

Between Mar and Oct 2016, we collected 170 fruits of Senegalia tenuifolia (L.) (Fabaceae) at 2 sampling sites (‘Pond 1,' 21.1228°S, 44.9780°W, and ‘Pond 2,' 21.2341°S, 44.9764°W) within the campus of the Federal University of Lavras, at Lavras, Minas Gerais State, southeastern Brazil. Monthly, at each area we collected 5 fruits that were immediately taken to the laboratory for dissection and inspection for insects. In addition, 5 other fruits were bagged with voile fabric. These bags were tied at the base of the pedicel, sealing the fruits within the bags and preventing the entry or exit of any arthropods. This procedure was performed to identify the arthropod community in the fruits on a monthly basis. The bagged fruits were kept in the trees until the end of the experiment. To remove the fruits, we used long stem pruning shears.

In Oct 2016, the bagged fruits were removed from the trees and taken to the laboratory, where the insects from the interior of the bags were collected. The seeds also were dissected to analyze their unemerged fauna (i.e., we excavated the unemerged individuals from inside and between the seeds). In 1 bag from the site ‘Pond 1,' a spider assigned to the genus Teudis Pickard-Cambridge, 1896 (Araneae: Anyphaenidae: Anyphaeninae) was observed, with signs of abdominal rupture. The spider was an adult female and, based on the relevant taxonomic literature, it was identified to the genus level through the examination of its genitalia (Brescovit 1997) (Fig. 1). The Neotropical genus Teudis has 27 described species, but it was never revised taxonomically, and many species were described more than 50 yr ago (World Spider Catalog 2017). The examined female was not recognized as 1 of the recently described or redescribed species (see Brescovit 1997) and, thus, it may represent an undescribed species. The spider is deposited at the spider collection from the Committee for Taxonomic Collections of the Federal University of Minas Gerais (Adalberto J. Santos, curator), at Belo Horizonte, Minas Gerais State, Brazil (voucher number UFMG 21353).

In the same bag, 1 specimen of the parasitoid Semaeomyia sp. (Hymenoptera: Evaniidae) was found (Fig. 2). No other insects were found in the fruit or in the bag, nor cockroach egg sacs from which the parasitoid could have emerged, suggesting that it likely parasitized the spider found within the bag. The parasitoid was sent to the Committee for Taxonomic Collections of the Federal University of Minas Gerais (UFMG; Fernando A. da Silveira, curator).

The arthropod system associated with S. tenuifolia fruits has been studied by L. D. B. Faria for approximately 7 yr. This fauna and its ecological interactions are well known from the following studies: Tuller (2013); Tuller et al. (2015); Maia (2016); Maia et al. (2017, 2018); and Silva et al. (2017). Spiders commonly are observed in these fruits, and probably feed on insects present in them, while cockroaches or egg capsules never were found, reinforcing the evidence of this new interaction.

This seems to be the first record of a host species for the genus Semaeomyia and the first record of an Evaniidae parasitizing a spider, because until now it was known only for parasitizing cockroach egg sacs. Direct natural history and host information are difficult to gather from Evaniidae, because they reproduce in cryptic hosts. Also, they are inconspicuous insects that spend most of their time wandering in dense vegetation (Deyrup & Atkinson 1993).

The Evaniidae remains a poorly studied wasp family (Deans 2011). This report may provide valuable insight into the natural history of this group, and we hope that it stimulates additional research with these intriguing animals.

Fig. 1.

Teudis sp. (Araneae: Anyphaenidae). (A) Female epigynum, ventral view. (B) Same, dorsal view. Abbreviations: CD, copulatory ducts; FD, fertilization ducts; H, hood; S, spermathecae; SR, seminal receptacles. Scale bar: 0.2 mm.

Authors would like to thank the Brazilian National Council for Scientific and Technological Development (CNPq) for the Master degree scholarship for T. Morales-Silva, and to the Minas Gerais Research Foundation (FAPEMIG) for the scientific initiation scholarship for B. M. Pedroso. We would also like to thank W. D. Ferreira and L. Oliveira for the assistance with the Evaniidae image. Author L. D. B. Faria thanks the Minas Gerais Research Foundation (FAPEMIG) and the Brazilian National Council for Scientific and Technological Development (CNPq) for financial support.

Fig. 2.

Semaeomyia sp. (Hymenoptera: Evaniidae). Scale bar: 500 μm.