Gregarines (Apicomplexa: Eugregarinorida) parasitizing the cave cricket Troglophilus (Orthoptera: Raphidophoridae) in the Slovenian karst

The cave crickets Troglophilus neglectus Krauss, 1879 and T. cavicola (Kollar, 1833) originating from caves in Slovenia were surveyed for gregarines. Two gregarine species were identified. Gregarina troglophili (Golemansky & Lipa, 1991) occurred in both cave cricket species, T. cavicola being reported a new host species. Besides, a new species, Gregarina bernardae sp. n., in­fecting T. neglectus, was identified and described. The two spe­cies often infest the same T. neglectus individuals, but can be well distinguished upon the shape and morphometric indexes of both solitary gregarines and associations. The deutomerite in solitary gamonts of G. troglophili is orbicular to broadly el­liptoid, while in G. bernardae sp. n. it is oblong to dolioform. In associations, the primite deutomerite in G. troglophili is orbicu­lar to broadly elliptoid, while in G. bernardae sp. n. it is shal­lowly oblong to oblong. In contrast to broadly obovoid to finely obdeltoid satellite deutomerite in G. troglophili, it is narrowly dolioform or dolioform to narrowly obdeltoid in G. bernardae sp. n. Both species are new to the faunal list of Slovenia, and to the list of cave-dwelling species in the country. We direct the attention to the parasite diversity of cave-dwelling animals – a promising, but understudied topic that might considerably contribute to the diversity of the subterranean fauna.

The subgenual organ complex in the cave cricket Troglophilus neglectus (Orthoptera: Rhaphidophoridae): comparative innervation and sensory evolution

Comparative studies of the organization of nervous systems and sensory organs can reveal their evolution and specific adaptations. In the forelegs of some Ensifera (including crickets and tettigoniids), tympanal hearing organs are located in close proximity to the mechanosensitive subgenual organ (SGO). In the present study, the SGO complex in the non-hearing cave cricket Troglophilus neglectus (Rhaphidophoridae) is investigated for the neuronal innervation pattern and for organs homologous to the hearing organs in related taxa. We analyse the innervation pattern of the sensory organs (SGO and intermediate organ (IO)) and its variability between individuals. In T. neglectus , the IO consists of two major groups of closely associated sensilla with different positions. While the distal-most sensilla superficially resemble tettigoniid auditory sensilla in location and orientation, the sensory innervation does not show these two groups to be distinct organs. Though variability in the number of sensory nerve branches occurs, usually either organ is supplied by a single nerve branch. Hence, no sensory elements clearly homologous to the auditory organ are evident. In contrast to other non-hearing Ensifera, the cave cricket sensory structures are relatively simple, consistent with a plesiomorphic organization resembling sensory innervation in grasshoppers and stick insects.