Leptostylum pulchellum Macquart, 1851

Gudin, Filipe Macedo & Messas, Yuri Fanchini, 2018, On taxonomy and hosts of Leptostylum Macquart, 1851 (Diptera: Tachinidae: Blondeliini), with description of a new species and a new host record, Journal of Natural History (J. Nat. Hist.) 52 (21 - 22), pp. 1395-1415 : 1409-1412

Leptostylum pulchellum Macquart, 1851

Leptostylum pulchellum Macquart 1851: 180 . Holotype male (described as female, see Wood 1985) (MNHN). Type locality: Brazil, Bahia.

Leptostylum pulchellum, Macquart 1851: 285 (plate 19, illustrations of dorsal habitus, head and antenna); Townsend 1892: 18 (catalogue); Townsend 1931: 179 (in synonymy with Argyreomyia busckii Townsend ); Townsend 1936: 245 (key to genera, tribe Trypherini ); Townsend 1941: 278 (catalogue); Guimarães 1971: 137 (catalogue); Wood 1985: 49 (catalogue, comparison to L. itaquaquecetubae and L. leuconotum ); Wood and Zumbado 2010: 1407 (comparison to L. leuconotum ); Evenhuis et al. 2016: 77 (catalogue of Macquart’ s genera).

Remarks

Although the validity of L. pulchellum has not been questioned since its proposition, some brief, but still important, changes were made in its classification. The genus Argyreomyia Townsend, 1915 , was described long after Leptostylum Macquart, 1851 , with A. busckii as genotype ( Townsend 1915). Later, another species, A. itaquaquecetubae , was described ( Townsend 1929). When examining MNHN’ s collection, Townsend put L. pulchellum in synonymy with A. busckii ( Townsend 1931) . However, when redescribing Leptostylum in his Manual of Myology, Townsend revalidated A. busckii as a valid species of Leptostylum ( Townsend 1941) . Therefore, there were three valid species of Leptostylum at the time: L. pulchellum , L. busckii and L. itaquaquecetubae .

Furthermore, Wood (1985) considered the possibility of L. itaquaquecetubae and L. leuconotum being synonymous with L. pulchellum , based on a few characters. Differences between L. leuconotum and both species were already pointed out in the Remarks section on L. leuconotum . Indeed, L. itaquaquecetubae shares with L. leuconotum many characters provided by Wood (1985) and by the original descriptions ( Macquart 1851; Townsend 1929). However, more specimens derived from respective type localities of both species are needed to resolve this issue.

Hosts of Leptostylum

Host record of Leptostylum oligothrix sp. nov.

At 08:30 on 20 April 2016 a fifth-instar specimen of Automeris naranja was found on a leaf of shrub vegetation, at 1.5 m above the ground ( Figure 7a ). The specimen presented an unusual behaviour, with sluggish and weak movements. After collection, the caterpillar died at night, attached to the leaf through its abdominal legs ( Figure 7b ). The next morning, 24 larvae of L. oligothrix sp. nov. ( Figure 7c ) were observed emerging from a single hole located in the lateromedial portion of the caterpillar body. Larvae began to pupate on the same day, with all specimens finishing the development of the puparium by the next day. Puparia, initially with a light brown colour, gradually changed to a dark brown colouration over a period of approximately 12 hours ( Figure 7c,d ). The first and the last adult fly emerged after 11 and 13 days, respectively. Only two adults did not emerge from their puparia. The sex ratio was not biased (0.83), since 10 males and 12 females were obtained. This is the first record of Leptostylum with identification at the species level; see host catalogue section.

Regarding oviposition strategies of Leptostylum , a trustworthy inference is still difficult to make. Blondeliini is a complex and diverse tribe, including oviparous and ovolarviparous species with different shapes of ovipositors ( Herting 1960; Wood 1985; Cantrell 1988). However, although there are no records of life cycle and oviposition strategies for Leptostylum species , the telescopic and simple shape of female terminalia of L. oligothrix sp. nov. suggests a direct oviposition on the host’ s cuticle, as observed on similar terminalia of other tachinid species ( Cantrell 1988). Whether eggs are embryonated or unembryonated, though, it is not possible to know.

Host catalogue of Leptostylum

Despite the fact that all known host records for species of Leptostylum are from saturniid caterpillars, Wood and Zumbado (2010) mentioned that host records for the genus are extensive for other families of Lepidoptera , based on the results of a project conducted by Janzen and Hallwachs (2009) with caterpillars in Costa Rica. This project provided a large data set of new host records for many parasitoids, including Tachinidae ( Fleming et al. 2014a, 2014b, 2015a, 2015b, 2015c, 2015d, 2016a, 2016b, 2017a, 2017b). Preliminary results indicate many new host records for Leptostylum species , which should be published as soon as these species are determined or described (D.H. Janzen 2017 pers. comm., email to FMG). Therefore, host records included in the host catalogue below are based only on officially published literature.

Leptostylum oligothrix Gudin and Messas sp. nov.

Host. Lepidoptera : Saturniidae : Hemileucinae Automeris naranja Schaus Gudin and Messas : 24 puparia, Brazil, São Paulo, Jundiaí, Base Ecológica da Serra do Japi.

Leptostylum spp.

Host. Lepidoptera : Saturniidae : Hemileucinae Automeris abdominalis Felder and Rogenhofer Stireman et al. 2009: 2 puparia (Leptostilum sp. 1a), Ecuador, Napo, Quijos Valley, YBS; 1 puparium ( Leptostylum sp. 3 ), Ecuador, Napo, Quijos Valley, YBS.

Automeris liberia (Cramer) Jacobson 1991: 33 puparia, Peru, Pasco, Villa Rica.

Gamelia neidhoeferi Lemaire

Stireman et al. 2009: 2 puparia (Leptostilum sp. 1), Ecuador, Napo, Quijos Valley, YBS.

Paradirphia geneforti Bouvier

Stireman et al. 2009: 1 puparium (Leptostilum sp. 4), Ecuador, Napo, Quijos Valley, YBS.

Pseudoautomeris yourii Lemaire

Stireman et al. 2009: 2 puparia (Leptostilum sp. 1), Ecuador, Napo, Quijos Valley, YBS.

Figures

Figure 7. Record of Leptostylum oligothrix Gudin and Messas sp. nov. parasitising a caterpillar of Automeris naranja Schaus (Saturniidae). (a) Fifth instar of A. naranja at prepupal stage, just before collection. (b) Death of caterpillar. (c) Emergence of third-instar larvae of L. oligothrix sp. nov. and beginning of pupation. (d) Puparia of L. oligothrix sp. nov.