CHALCIDOID PARASITOIDS (HYMENOPTERA: CHALCIDOIDEA) ASSOCIATED WITH SIBINIA SUBELLIPTICA (DESBROCHERS, 1873) (COLEOPTERA: CURCULIONIDAE) IN BULGARIA

The weevil Sibinia subelliptica (Desbrochers, 1873) and a rich complex of associated chalcidoid parasitoids were reared from inflorescences of Dianthus giganteus d’Urv. (Caryophyllaceae) in Bulgaria. The following taxa were identified: Aprostocetus venustus (Gahan) and Baryscapus sp. near garganus (Domenichini, 1958) (Eulophidae); Eupelmus barai Fusu and E . microzonus Förster (Eupelmidae); Aximopsis augasmae (Zerova), A . collina (Zerova), Eurytoma coleophorae Zerova and E . coleopterae Zerova (Eurytomidae ); Catolaccus crassiceps (Masi) and Pteromalus ochrocerus (Thomson) (Pteromalidae); and Exopristus trigonomerus (Masi) (Torymidae). Two of these, E . coleophorae and E . coleopterae , are new records for Bulgaria. All parasitoid-host relationships are documented here for the first time. New plant associations with D. giganteus are recorded here for all reared parasitoids except E. barai and E. microzonus . The new trophic association of S. subelliptica with D. giganteus is established here.

The genus Dianthus L. (Caryophyllaceae) is represented by annual, biennial and perennial herbaceous plants (Kirillov et al., 2016). It is widespread mainly in Europe, the Mediterranean region and in Asia, and a few species are known  Since only 1/7 of the inflorescences were dissected, the number of beetles in them can be expected to exceed 3500 individuals. In addition to these, we obtained hundreds of thrips (Thysanoptera) and four specimens of unidentified species of Chrysopidae (Neuroptera). Whilst S. subelliptica was not proven to be the host species of all these parasitoids, we believe that it was very probably the host (primary or secondary) of at least the most frequently reared Hymenoptera. Two of the parasitoid species, Eurytoma Arbanasi Village near Veliko Tarnovo (43°05'50.1" N 25°40'38.3" E, 417 m). The collected material was stored in laboratory conditions in plastic bottles darkened with an aluminium foil and with an additional transparent tube at temperature 23-26° C. The tops of the bottles were cut out and covered with white cheesecloth. The material was stored for at least one year until all emergences had ceased. Emerged parasitoids were aspirated with a pooter, fixed in ethanol and later examined under a stereo microscope. During the dissection of at least 300 inflorescences, we found 500 imagos of S. subelliptica at the base of the flowers (Fig. 1). Only 12 specimens were observed outside the inflorescences.
The specimens are preserved in the authors' collection (University of Plovdiv and Institute of Biodiversity and Ecosystems Research, Bulgarian Academy of Sciences).
Colour photographs were taken with a Canon 5D Mark III digital camera.

Results
During the study we reared 512 specimens of S. subelliptica, along with 905 specimens of hymenopteran parasitoids belonging to 11 species (Table 1)   (Coleoptera: Curculionidae) and a rich complex of hymenopteran parasitoids associated with this beetle . We found no information in the literature for previous rearings of this eulophid species from D. giganteus. Baryscapus Förster, 1856 is a large and biologically diverse genus in the subfamily Tetrastichinae (Eulophidae) (Graham, 1991) comprising 128 species with a cosmopolitan distribution (Noyes, 2019). Species of the genus develop mostly as gregarious or more rarely as solitary endoparasitoids of larvae or pupae of a wide variety of insect hosts belonging to Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera and Neuroptera. Some species of Baryscapus are secondary parasitoids of species of the families Braconidae and Ichneumonidae and of the superfamilies Chalcidoidea and Cynipoidea (Graham, 1991). We assume that Baryscapus sp. near garganus is an undescribed species and differs from females of B. garganus mainly in structure of antennae and thorax as well as the longer abdomen. Its taxonomic characterization will be a subject of further studies.
Eupelmus microzonus is a polyphagous parasitoid attacking the larvae and pupae of a wide range of insect hosts that are usually concealed in galls, flower heads, seeds, grass stems or cocoons and belong to Coleoptera, Diptera, Hymenoptera and Lepidoptera coleophorae and E. coleopterae, are recorded for the first time from Bulgaria. All parasitoids are suggested to be associated with S. subelliptica for the first time and, with the exception of E. barai and E. microzonus, all parasitoid species are newly associated with D. giganteus. Also, D. giganteus is recorded here as a new host plant of S. subelliptica.
Although we cannot conclusively confirm that all reared parasitoids are primary parasitoids of S. subelliptica, their large number (with the exception of C. crassiceps and E. coleophorae) suggests a more common than accidental association with this host.

Discussion
The review of the literature shows that there are no data about parasitoids of S. subelliptica. However, parasitoids belonging to four families of Chalcidoidea (Eulophidae, Eupelmidae, Eurytomidae and Pteromalidae) and one family of Ichneumonoidea (Braconidae) have been recorded on eight other Sibinia spp. (Table 2).