Blastocrithidia frustrata sp. n. (Kinetoplastea, Trypanosomatidae) from the brown marmorated stink bug Halyomorpha halys (Stål) (Hemiptera, Pentatomidae)

Abstract

The article describes a new species of monoxenous trypanosomatids Blastocrithidia frustrata from brown marmorated stink bugs Halyomorpha halys collected in the south of Russia (Sochi) and Abkhazia (Sukhumi). A unique morphological feature distinguishing this new species from the earlier described representatives of the genus Blastocrithidia is a developed zone of flagellum attachment to rostrum (FAZ), which is represented by macular hemidesmosomes. The presence of FAZ used to be considered a characteristic feature of dixenous flagellates of Trypanosoma genus. Phylogenetic analyses based on sequences of 18S rRNA gene has demonstrated that B. frustrata is included into the monophyletic cluster within the limits of the clade comprised of Blastocrithidia spp. This cluster includes, among others, the isolates, which were earlier identified among the Hemiptera in China (Typing Units Ch7) and Papua New Guinea (TU63). Isolates 332 MK and 4femMK, which we address in our research, prove to be 100% identical to the isolates from Ch7 and TU63 in terms of sequences of 18S rRNA. However, our experimental deciphering of the life cycle of B. frustrata in H. halys revealed an unstable pattern of infections. Although the development of these trypanosomatids in the host after experimental infection occurs according to the scenario typical for Blastocrithidia and results in the formation of cyst-like amastigotes (=straphangers), the vertical transmission of parasites (from parent to offspring) does not take place, while horizontal one occurs rarely, if ever. This allows to conclude that H. halys is a nonspecific host for B. frustrata.