The tachinid species Euthera fascipennis (Loew, 1854) belongs to the tribe Eutherini, a small group of bug-killing flies, with uncertain phylogenetic affinities (O’Hara, 2012). The tribe consists of two genera: the cosmopolitan Euthera Loew, 1866 with 13 species and the Palaearctic, monotypic Redtenbacheria Schiner, 1861. Euthera fascipennis is the only representative of the genus in Europe (Pape et al. 2015) and is also found in North Africa and the Afrotropical and Oriental regions. This small tribe has been traditionally assigned to the Phasiinae, primarily because its members parasitize pentatomids (Crosskey 1976; Tschorsnig & Richter 1998). Other studies, including recent ones, have placed Eutherini in the Dexiinae (see O’Hara 2013, and references therein).
The genus Euthera includes some of the most striking and beautiful tachinids, the general aspect of which recalls that of the tabanid genus Chrysops Meigen, 1803 (Fig. 1). Yet, records of Euthera species are scarce in the literature and specimens, let alone reared ones, are not abundant in collections. Females are known to be ovolarviparous [Cerretti (2010) stated oviparous in error], laying ready-to-hatch plano-convex eggs directly on the bodies of their hosts. Little is known about the ecology of these parasitoids, although they seem to be attracted to pheromones of their hosts (Aldrich et al. 2007).
Halys dentatus (Fabricius) and Apodiphus amygdale (Germar) (Heteroptera: Pentatomidae) were respectively recorded as hosts of E. fascipennis in the New Delhi area of North India (Sabrosky 1965, as E. mannii Mik) and in the Kemalpasa District of western Turkey (IOBC 1993; see also Tschorsnig 2017). No hosts of E. fascipennis in Europe have been previously reported. Of the two aforementioned pentatomid species, only A. amygdale is known from Europe (including mainland Italy and the Balkans; Rider 2006), but it has so far not been recorded there as a host of E. fascipennis.
Since 2015, field surveys on tachinid parasitoids of pentatomids have been conducted at the Department of Agricultural Sciences (DipSA) of the University of Bologna (Italy). Adults of different pentatomid species were collected in different areas of the Emilia Romagna Region (North Italy). All samples were transferred to the laboratory of DipSA and maintained at 25°C ±1°C, 70% RH and 16:8 L:D (Dindo et al. 2007). For each date of sampling, the insects were placed inside plastic boxes of 13 x 36 x 24 cm, with a perforated cover closed with a fine metallic mesh, to allow ventilation (one species per box). All pentatomids were fed with soybean seeds (Glycine max [L.] Merrill), sunflowers seeds (Helianthus annuus L.) and fresh green beans (Phaseolus vulgaris L.). The boxes were checked daily for tachinid puparia. Puparia from each host species were collected and placed in plexiglass cages of 20 x 20 x 20 cm, under the same rearing conditions as described above. A plastic cylinder with water, covered with a net, was inserted in each cage to increase humidity and promote emergence (Dindo & Grenier 2014).
During these surveys, a puparium was obtained from an adult of Dolycoris baccarum (the sloe bug), collected from Crevalcore (Bologna Province) (44°43.21′N, 11°09.32′E) on November 2, 2016. An adult of E. fascipennis emerged nine days later. Dolycoris baccarum is a small pentatomid (7–12 mm) native to the western Mediterranean area and is widespread in Europe and parts of Asia (i.e., India, China and Japan) (Panizzi et al. 2000; Nakamura & Numata 2006). This species is also known to be parasitized by the following phasiine tachinids in Europe: Ectophasia crassipennis (Fabricius), E. oblonga (Robineau-Desvoidy), Gymnosoma carpocoridis Dupuis, Gymnosoma clavatum (Rohdendorf), G. dolycoridis Dupuis, G. rotundatum (Linnaeus), Elomya lateralis (Meigen), Cylindromyia auriceps (Meigen), C. brassicaria (Fabricius), and C. brevicornis (Loew) (Tschorsnig 2017). Interestingly, all of these other tachinid species occur in Italy (Cerretti 2010) but none has been recorded there as a parasitoid of D. baccarum (Cerretti & Tschorsnig 2010). The association between E. fascipennis and D. baccarum is reported here for the first time. Moreover, E. fascipennis had so far been recorded only in southern Italy, this is the first record of this tachinid in northern Italy.