Claudio Di Russo

The cave crickets of northeast Turkey and transCaucasian regions, with descriptions of two new species of the genera Dolichopoda and Troglophilus (Orthoptera, Rhaphidophoridae)

Abstract Until now, of the total 53 or so species of cave crickets in the genera Troglophilus Krauss 1879 and Dolichopoda Bolivar 1899, seven are known from Turkey. Collecting journeys in 2000 and 2001 allowed us to obtain samples from the Pontic Mountains (northeastern Turkey). Based on this material, we now describe two new species, one for each of the above genera. Dolichopoda noctivaga sp. n. is very closely related to the transCaucasian species D. euxina and D. hyrcana, but can be distinguished from them by the shape of the epiphallus, rounded not truncate apically, by the occurrence of styli on the male subgenital plate, and by the unemarginate apex of the female subgenital plate. The second newly discovered species, Troglophilus tatyanae sp. n., differs from all other Turkish species in the uniformly brown coloration of its body, and by its small size — the smallest species known for the genus Troglophilus. Both T. tatyanae and D. noctivaga are apparently limited to the Black Sea region of northeast Turkey. D. noctivaga has been found in four localities scattered across the Pontic Mountains. By contrast, T. tatyanae occurs only in one locality, that in the Artvin district where it is syntopic with D. noctivaga. Both species have only a slight degree of adaptation to cave habitats, which seem to be used only as seasonal shelter.

Contrasting age structures in cave cricket populations: patterns and significance

Abstract. 1 Adaptation to life in caves, as a seasonally constant environment, is expected to affect several life history traits. In this paper we investigate the age structure and phenology of twenty‐seven Dolichopodu cave cricket populations from artificial and natural caves subjected to different environmental regimes and to different availability of food resources. 2 Morphometric data clearly revealed the occurrence of different age structures and phenology, basically indicating two contrasting patterns. 3 In artificial caves, which have been colonized by Dolichopoda only in historical times and where food resources and climate are chiefly dependent upon surface environment, age structure was seasonal. In contrast, in most natural caves, where cricket colonization appears to be much older and stability of both climatic parameters and trophic resources is higher, age structure was diverse and aseasonal. 4 However, a seasonal age structure also occurs in natural caves characterized by either recent origin or by a low temperature regime. This suggests that age structure in Dolichopoda is influenced by historical factors, stability of food resources and also by environmental stress.

Life-history variation in Dolichopoda cave crickets

Two life-cycle patterns can be identified in heterospecific or conspecific populations of Dolichopoda cave crickets. One pattern, typical of populations living in artificial caves, is characterized by strong seasonality in the age structure, egg and nymphal diapause and reproductive period. The second pattern, typical of populations inhabiting natural caves, is characterized by absence of such seasonality. These seasonal and aseasonal life cycles also involve demographic differences. In particular aseasonal populations have smaller clutches and larger eggs than seasonal populations. Moreover, studies on several populations revealed that the natural caves tend to hold smaller populations.

Life cycle and age structure of Dolichopoda populations (Orthoptera, Raphidophoridae) from natural and artificial cave habitats

Abstract Life cycle, phenology and age structure have been studied in three Dolichopoda populations belonging to the loetitiae‐geniculata species complex. One of these populations inhabits a natural limestone cave (Valmarino Cave, VAL), the other two live in artificial tufa caves (Tuscolo, TUS; Tunnel of Veio, VEI). Morphometric data were collected periodically both in the field and in laboratory experimental breedings (TUS population). The life cycle of the TUS population lasts 25–28 months and involves 9 pre‐imaginal instars. In the artificial cave populations (TUS, VEI), two different cohorts have been recognized, which alternate yearly. On the contrary, the separation in cohorts is not apparent in the natural cave population (VAL). Mortality rates and age structure have been studied in the three populations. The results strongly suggest the occurrence of alternative adaptive strategies related to the different selective pressures operating in the artificial vs natural caves.

Four new species of Dolichopoda Bolivar, 1880 from Southern Sporades and Western Turkey (Orthoptera, Rhaphidophoridae, Dolichopodainae).

Abstract A description of four new species of Dolichopoda Bolivar, 1880 (Orthoptera, Rhaphidophoridae) from Eastern Aegean region (Southern Sporades), including Western Turkey, is reported. This brings to a total of 11 the number of Dolichopoda species recorded for caves of the Aegean area. Overall, these species show a high degree of morphological homogeneity and they are very close to Dolichopoda paraskevi Boudou-Saltet, 1973 from Crete and Dolichopoda naxia Boudou-Saltet, 1972 from Cyclades (Naxos Island). The Western Turkish species are morphologically not closely related to the other Anatolian species; this suggests an independent origin for the taxa occurring in the Southern Taurus and Black Sea regions. These new data help to better define the already high level of diversity of the Hellenic Dolichopoda and strengthen the hypothesis that the central area of dispersal for the genus would correspond to the ancient Aegean plate.

Long term stability of a terrestrial cave community

We report data on the spatial structure and seasonal variation of the community of Valmarino cave, a medium sized sandstone cave, located a few kilometres from the coast line, in Central Italy. Due to both its habitat features and its relatively recent geological history, Valmarino cave is only inhabited by terrestrial, troglophilic elements, i.e, facultative cave dwellers. By means of monthly censuses and density plot estimates we have investigated species abundance, diversity and their spatial organization, by considering separately samples from different cave sectors. Homogeneous sampling design allowed to compare series of samplings performed in 1974 and 1994. On the whole 21 arthropods and one snail species constitute the cave community. Ordination plots resulting from correspondence analyses of monthly samples outline a distinct spatial and temporal structure. Two main sub-communities can be identified: a inner subcommunity, mainly represented by eu-troglophilic species, showing a remarkable stability throughout the year and an outer sub-community, mainly represented by sub-troglophilic species, showing strong seasonal variation. Both spatial and temporal vectors show similar importance in shaping the community structure. An interesting result of this study is the long term stability of both spatial and seasonal components of the community structure which remained almost identical after 20 years, as shown by the comparison of ordination plots obtained from 1974 and 1994 sampling series. Therefore this study provides empirical evidence of a frequently hypothesised, albeit never demonstrated feature of the cave ecosystem.

Phylogeography and systematics of the westernmost Italian Dolichopoda species (Orthoptera, Rhaphidophoridae)

Abstract The genus Dolichopoda (Orthoptera; Rhaphidopohoridae) is present in Italy with 9 species distributed from northwestern Italy (Piedmont and Liguria) to the southernmost Apennines (Calabria), occurring also in the Tyrrhenian coastal areas and in Sardinia. Three morphologically very close taxa have been described in Piedmont and Liguria, i.e., D. ligustica ligustica, D. ligustica septentrionalis and D. azami azami. To investigate the delimitation of the northwestern species of Dolichopoda, we performed both morphological and molecular analyses. Morphological analysis was carried out by considering diagnostic characters generally used to distinguish different taxa, as the shape of epiphallus in males and the subgenital fig in females. Molecular analysis was performed by sequencing three mitochondrial genes, 12S rRNA, 16S rRNA, partially sequenced and the entire gene of COI. Results from both morphological and molecular analyses highlighted a very homogeneous group of populations, although genetically structured. Three haplogroups geographically distributed could be distinguished and based on these results we suggest a new taxonomic arrangement. All populations, due to the priority of description, should be assigned to D. azami azami Saulcy, 1893 and to preserve the names ligustica and septentrionalis, corresponding to different genetic haplogroups, we assign them to D. azami ligustica stat. n. Baccetti & Capra, 1959 and to D. azami septentrionalis stat. n. Baccetti & Capra, 1959.

Molecular systematics of the genus Troglophilus (Rhaphidophoridae, Orthoptera) in Turkey: mitochondrial 16s rDNA evidences

Abstract This study focuses on the evolutionary relationships among Turkish species of the cave cricket genus Troglophilus.Fifteen populations were studied for sequence variation in a fragment (543 base pairs) of the mitochondrial DNA (mtDNA) 16S rDNA gene (16S) to reconstruct their phylogenetic relationships and biogeographic history. Genetic data retrieved three main clades and at least three divergent lineages that could not be attributed to any of the taxa known for the area. Molecular time estimates suggest that the diversification of the group took place between the Messinian and the Plio-Pleistocene.

A recent colonization of Dolichopoda cave crickets in the Poscola cave (Orthoptera, Rhaphidophoridae)

We report a series of investigations carried out on a Dolichopoda population recently discovered in the Poscola cave and in some small caves nearby (Lessini Mountains, Vicenza). This population is located north of Po river, outside the present known geographic range of this genus in Italy. Morphology of the epiphallus corroborated by chromosome and allozyme analysis indicated that this population belongs to D. laetitiae. Study of the genetic structure of population in the Poscola area revealed high gene flow levels between Poscola and the other minor caves, suggesting the occurrence of a single expanding population. This finding as well as mark-recapture data on population size, migrations, age structure and habitat type strongly suggest that the Poscola population is the result of a recent colonization due to anthropocore dispersal.

Restriction enzymes induced bands in the cave cricket Dolichopoda schiavazzii (Orthoptera, Rhaphidophoridae): Implications for heterochromatin characterization and satellite DNA distribution

Abstract In this study the activity of some class II restriction endonucleases, RE, on fixed metaphase chromosomes has been tested on two sample populations of the cave cricket Dolichopoda schiavazzii, a species endemic in Tuscany. In particular, the 6‐base cutter PstI was chosen to detect the occurrence and localization on chromosomes of a satellite DNA family (named pDoP102) whose repetition units, analyzed in a previous study, contain the cleavage site of this enzyme. A comparison of the PstI digestion pattern and the C‐banding one, suggests that this satDNA family is mainly localized in certain heterochromatic regions of chromosomes 1, 3, 8, 10 and in the Y chromosome. As a negative control in situ digestion was performed with RE AluI whose cleavage site is not contained in the pDoP102 satDNA sequence. The partial overlap between the PstI and Alul digested regions suggests the occurrence of at least another satDNA family detected by PstI and containing the Alul target. Alul restriction banding also sh...