Fabio Bernini

The Berger–Parker index as an effective tool for monitoring the biodiversity of disturbed soils: a case study on Mediterranean oribatid (Acari: Oribatida) assemblages

Recent data on oribatid mites (Acari: Oribatida) indicates that Mediterranean soil communities tend to show uneven patterns of species abundance distribution (SAD) that are well fitted by a simple model such as the geometric series. In the case of linear distributions, the fraction of total sampled individuals that is contributed by the most abundant species, known as the Berger–Parker index, synthetically describes the SAD of disturbed communities. This study assessed the bioindicator potential of the Berger–Parker index by comparing its variations among Mediterranean oribatid assemblages under different types of soil disturbance. The index significantly changes between undisturbed and disturbed soils reaching the highest values in areas with strong physical disturbance due to agricultural management. The Berger–Parker index is therefore a practical and effective tool for monitoring biodiversity impairment linked to human disturbance in soil ecosystems.

Current ideas on the phylogeny and the adaptive radiations of Acarida

Abstract In this paper, the present classification and ideas on the evolutionary history of the Acarida are examined. Besides the more usual characteristics relative to the body segmentation, tagmata, tracheae and stigmata, setal birefringency, post‐embryonal development, podocephalic canal and sperm morphology, the fossil remains and the geographic distribution of Acarida are also considered. These data do not give a definite answer to the fundamental question of the acarid phylogeny, namely, whether this group is mono‐or polyphyletic. However, an attempt to outline the evolutionary history and detect the starting points for the adaptive radiations of the Acarida is made on the basis of the known elements. Presumably the early actinotrichid lineages passed onto the land with the terrestrial plant invasion, behaving first either as phytophages on plants, fungal mycelia and bacteria (Actinedida and Oribatida) or as saprophages, probably forming intimate relationships with fungi (Actinedida and Oribatida), ...

The spermatozoon of arthropoda: XXIII. The “9+9+3” spermatozoon of simuliid diptera

The authors describe a new model of sperm axoneme, the “9 + 9 + 3,” which is characteristic of simuliid Diptera. Each of the three central tubules has a row of very long side projections rich in ATPase activity, but the flagellum lacks the central sheath. Sperm motility is normal, like that of sperm having a “9 + 9 + 2” axoneme model and accessory bodies.

Comparative analysis of two edaphic zoocoenoses (Oribatid mites and Carabid beetles) in five habitats of the 'Pietraporciana' and 'Lucciolabella' Nature Reserves (Orcia Valley, central Italy)

Abstract Oribatid mite and Carabid beetle communities were investigated at five sites in the ‘Pietraporciana’ and ‘Lucciolabella’ Nature Reserves (central Italy). In this part of southern Tuscany many attempts have been made to encourage the regeneration of native habitats and to preserve existing ones. Human-induced changes in the original forest landscape have had a direct impact on mite and carabid populations. Significant differences in species diversity and abundance among different sites were revealed throughout the sampling period. Species richness, abundance and diversity of oribatid mites decrease from woodland sites to open habitats where evenness was high. There is an inverse trend between the number of species and richness of carabid beetles and those of oribatid mites. Canonical correspondence analysis (CCA) of oribatid and carabid beetle compositions discriminated the sites, demonstrating how even small areas with different vegetation, composition, structure, environment and microclimate were characterised by distinct edaphic populations.

Investigation on the taxonomic status of Steganacarus magnus and Steganacarus anomalus (Acari: Oribatida) using mitochondrial DNA sequences

To test the previously suggested synonymization of S. anomalus with the older S. magnus, a fragment of the mitochondrial COI gene was amplified via the polymerase chain reaction and sequenced. The sequence variation was examined in a total of 327 base pairs for four steganacarid mite populations, two of which belong to S. anomalus, one to S. magnus and one to S. hirsutus. The sequence variation suggests that S. magnus and S. anomalus are not distinct species and that the population from Fioreta (Siena) is more similar to that from Apulia than to the nearer population from the Apuan Alps. The results show the usefulness of this molecular approach as a tool for determining taxonomic status and for suggesting faunistic movements in the past millions of years.

Comparative analysis of two edaphic zoocoenoses (Acari Oribatida; Hexapoda Collembola) in the area of Orio al Serio Airport (Bergamo, northern Italy)

Species richness, abundance and diversity of oribatid mites and springtails in soil and litter were investigated at four sites in the area of Orio al Serio Airport (Bergamo, Italy). A total of 60 oribatid mite and 35 springtail species were collected from the sites. The general low diversity and evenness along with high dominance may be related to the sensitivity of these edaphic zoocoenoses to soil impoverishment which has been occurring in this part of the Italian pre-Alps for many years. Quantitative and qualitative differences were found among the investigated areas. Results show that less frequently disturbed soils are capable of restoring oribatid and springtail populations, leading to greater equilibrium. Results show that less frequently disturbed soils allow the restoration of more equilibrated oribatid and springtail populations. Species were divided into 8 autoecological and 11 chorological categories. Correspondence Analysis arranged these categories among the sites, confirming the above-mentioned trend.

The spermatozoon of arthropoda. XXV. A new model of tail having up to 170 doublets: Monarthropalpus buxi

Abstract The spermatozoon of M. buxi which belongs to the Cecidomyiidae family have been studied. The spermatozoa have an aberrant flagellum somewhat similar to that of Sciaridae formed by about 170 doublets ranged in rows to form a compact bundle. Accessory tubules and all the other axonemal structures are missing. The sperm is characterized by the lack of acrosome, and by the presence of normal mitochondria apically gathered before the nucleus.

Notulae oribatologicae XLI. some new Steganacarus species belonging to the magnus group (Acarida, oribatida)

Abstract Two new species closely related to Steganacarus (Steganacarus) magnus (Nicolet) are described. S. (S.) michaeli can also be genetically differentiated from known congeneric species such as S. (S.) hirsutus Perez-Inigo by biochemical methods. Some biogeographic observations are made about the collection sites of the two new entities.

Notulae oribatologicae XLVIII. the taxonomic position of Steganacarus brevipilus (Berlese, 1923) and Tropacarus in the Steganacaridae system (Acarida, Oribatida)

Abstract The classical species, Steganacarus (Tropacarus) brevipilus (Berlese, 1923), was analyzed morphologically, biogeographically and genetically in order to exactly define its taxonomic position in the Steganacarid system. The traditional morphological character of the median notogastral ridge and the gene-enzyme systems confirm the close affinity of brevipilus to S. (T.) carinatus (Koch) and the validity of subgeneric rank for Tropacarus.

Notulae oribatologicae XLVII. Intraspecific variability in Tropacarus: The example of Steganacarus (Tropacarus) pulcherrimus (Berlese, 1887) junior synonym of S. (T.) carinatus (Koch, 1841) (Acarida, Oribatida)

Abstract Morphological, ecological, biogeographic and genetic evidence is presented to suggest the synonymy of Steganacarus (Tropacants) pulcherrimus (Berlese) and the earlier S. (T.) carinatus (C.L.Koch).