Giuseppe Montesanto

Diversity of terrestrial isopods in a protected area characterized by salty coastal ponds (Vendicari, Sicily)

The diversity of Oniscidean isopods was studied in Vendicari, a protected area in southeastern Sicily characterized by salty ponds separated from the sea by narrow bands of land. Samples were collected in pitfall traps placed in transects from the coastline to the ponds and from the ponds inland. Twenty-three species were identified, only seven of which were present at all sampling sites. Shannons diversity and Pielous evenness indices revealed higher values in the spring and autumn; activity indices were also calculated for each species for all months of the year. Similarity among sampling sites was evaluated qualitatively with Jaccards index and quantitatively with Sørensens index. The ponds seem to play the same role as the seacoasts regarding species zonation.

A fast GNU method to draw accurate scientific illustrations for taxonomy

Abstract Nowadays only digital figures are accepted by the most important journals of taxonomy. These may be produced by scanning conventional drawings, made with high precision technical ink-pens, which normally use capillary cartridge and various line widths. Digital drawing techniques that use vector graphics, have already been described in literature to support scientists in drawing figures and plates for scientific illustrations; these techniques use many different software and hardware devices. The present work gives step-by-step instructions on how to make accurate line drawings with a new procedure that uses bitmap graphics with the GNU Image Manipulation Program (GIMP). This method is noteworthy: it is very accurate, producing detailed lines at the highest resolution; the raster lines appear as realistic ink-made drawings; it is faster than the traditional way of making illustrations; everyone can use this simple technique; this method is completely free as it does not use expensive and licensed software and it can be used with different operating systems. The method has been developed drawing figures of terrestrial isopods and some examples are here given.

The diversity of terrestrial isopods in the natural reserve "Saline di Trapani e Paceco" (Crustacea, Isopoda, Oniscidea) in northwestern Sicily.

Abstract Ecosystems comprising coastal lakes and ponds are important areas for preserving biodiversity. The natural reserve “Saline di Trapani e Paceco” is an interesting natural area in Sicily, formed by the remaining strips of land among salt pans near the coastline. From January 2008 to January 2010, pitfall trapping was conducted in five sampling sites inside the study area. The community of terrestrial isopods was assessed using the main diversity indices. Twenty-four species were collected, only one of them endemic to western Sicily: Porcellio siculoccidentalis Viglianisi, Lombardo & Caruso, 1992. Two species are new to Sicily: Armadilloniscus candidus Budde-Lund, 1885 and Armadilloniscus ellipticus (Harger, 1878). This is high species richness for a single reserve in Sicily. The extended sampling period also allowed us to study species phenology. Most of the species exhibited higher activity in spring than in autumn while some species also exhibited lower activity in the summer. The species richness revealed that the study area is in an acceptable conservation status; Shannon and Pielou indices also confirmed a more or less even distribution of individuals belonging to different species.

Plant communities preferences of terrestrial crustaceans (Isopoda: Oniscidea) in a protected coastal area of southeastern Sicily (Italy)

We studied the plant communities preferences of oniscidean isopods in a protected coastal area in southeastern Sicily that is characterized by ponds, dunes and rocky coast. In total, five sites were sampled between March 2003 and February 2004 using pitfall traps. A total of 7,326 specimens were found, belonging to 23 species. The vegetation analysis, using the phytosociological method, recognized a total of 11 types of plant communities, with specific ecological features. Measuring the species richness, diversity and annual activity density (aAD) values of the terrestrial isopod communities from each sampling site revealed differences among the various plant communities. PCA analysis confirmed the correlation between isopods species and specific plant communities. Moreover our results show that the high species richness is associated with a high vegetation cover and number of plants.

The postmarsupial development of Porcellio siculoccidentalis, with some data on reproductive biology (Crustacea, Isopoda, Oniscidea)

Abstract In the broader context of research on the Sicilian Porcellio imbutus-complex, the postmarsupial development of Porcellio siculoccidentalis Viglianisi, Lombardo & Caruso, 1992 was studied in detail. This research was conducted in the laboratory under controlled conditions, allowing us to follow the stages of development, from the formation of the marsupium in ovigerous females until the larval stages and development of the seventh pair of legs. The timing of developmental stages and the morphological modifications of appendages in the postmarsupial manca stages (M I–M III) are described. The manca stage M I had a duration of about one hour. Ovigerous females were collected and reared separately, and the number of parturial molts in the absence of males was counted. The results showed a maximum of four successive parturial molts. Fecundity and fertility were evaluated as the number of eggs and embryos, respectively, inside the marsupium of the ovigerous females. Both parameters were positively correlated with the size of the females. The maximum numbers of eggs and embryos in the marsupium were 113 and 141, respectively. Data describing the total number of postmarsupial mancas released per month indicated that the highest release occurred in April.

Genetic and morphological analysis of Tunisian populations of Porcellio variabilis Lucas (Crustacea, Isopoda, Oniscidea)

Specimens of Porcellio variabilis coming from Tunisian populations were genetically and morphologically examined. Ten loci were analysed by Multilocus Enzyme Electrophoresis (Mdh 1, Mdh 2, Idh 1, Idh 2, Got 1, Got 2, Pgm, Est 1, Acph, Phi). The low values of genetic distance (average DN = 0.101) and the morphological differences found between the various populations do not allow a clear separation, even if the population of Ain Drahem shows the most significant differentiation with respect to all the others (about 0.150 for DN values).

Iridovirus infection in terrestrial isopods from Sicily (Italy)

During our researches on systematics and ecology of terrestrial isopods, carried out in western Sicily, some specimens showing a blue-purple coloration were collected; they belonged to four species: Armadillidium decorum Brandt, 1833, Trichoniscus panormidensis Montesanto et al., 2011, Philoscia affinis Verhoeff, 1908, Porcellio siculoccidentalis Viglianisi et al., 1992. We hypothesized that such coloration could be due, as reported in literature, to characteristic paracrystalline arrays of virions inside the tissues of blue colored specimens. Ultrastructural observations by transmission electron microscopy, on tissues of A. decorum, showed the presence of electron-dense viral particles, with a diameter of nearly 0.12μm. Dual-axis tomography, performed on specimens of A. decorum, evidenced an icosahedral structure of viral particles matching with that of Isopod Iridescent Virus (IIV). Molecular analysis, on 254bp portion of the major capsid protein (MCP) gene, allowed to place the virus into IIV-31 group, already known for other oniscidean species. The symptoms of infected individuals and the course of the disease were followed in laboratory, indicating similarities with other studies on Isopod Iridoviruses. Moreover, some notes on reproduction of infected ovigerous females are reported. Our data support unequivocal and direct evidences for the first case of IIV infection in terrestrial isopods reported in Italy.

A new species and new records of terrestrial isopods from Sicily (Isopoda: Oniscidea)

In this paper three species of terrestrial isopods from Sicily are discussed. Spelaeoniscus coiffaiti and Cylisticus convexus are new to the Sicilian fauna. Sicilian specimens of Spelaeoniscus coiffaiti are examined and illustrated, and the biogeographical significance of this species in Sicily is discussed. Trichoniscus panormidensis is described as a new species, and the affinities are treated.

A crossover design to assess feeding preferences in terrestrial isopods: a case study in a Mediterranean species

Abstract A crossover design was used to study food preferences and capability of nutritional acclimation to different food sources in terrestrial isopods, which live in xeric environments, by using Armadillo officinalis as an experimental model. The foods chosen for this experiment were three fresh foods with different content of water (potato, carrot, lettuce), and a dry food (leaf of plane tree). In order to quantify these preferences, two kinds of data able to provide complementary information were collected: number of droppings produced and food ingested per week. These data were used to fit some mixed effects models, in order to highlight statistically significant differences among the foods provided to the animals at a level of preferences. In addition, the buccal appendages of A. officinalis were observed and drawn in details, to provide further information at this level. Our results showed that A. officinalis seems not to have particular preferences between fresh foods with a moderate quantity of water and dry food, commonly eaten in its natural habitat. In contrast, foods with high quantity of water, like the lettuce, seem not to be instead particularly palatable for its taste, or its nutritional needs. Also, this study seems to have highlighted a better capability of digestion and absorption of the potato tuber compared to the leaf of plane tree for an equal quantity of ingested food. Anyway, this hypothesis needs further insights in order to be able to be verified.

Changes in turn alternation pattern in response to substrate-borne vibrations in terrestrial isopods

The present study focuses on the relationship existing between the phenomenon of turn alternation and substrate-borne vibrations in woodlice. Armadillo officinalis was utilized as a behavioral model in comparison to Armadillidium vulgare so as to assess its capability of perceiving external vibrations too. A T-maze with multiple exits was used to collect information on the pattern of turn alternation in i) adult individuals of A. officinalis exposed, and ii) not exposed to micro-vibrations, and iii) adult individuals of A. vulgare exposed to micro-vibrations. Turn alternation was assessed as the number of times that an animal turned on the opposite side in the T-maze. Our results showed a statistically significant association between turn alternation pattern and both exposure to micro-vibrations and species of the animals. According to our best-fitting model, A. officinalis not exposed and A. vulgare exposed to substrate-borne vibrations have 97% and 98% lower odds, respectively of being in a higher category of turn alternations compared to a lower category than exposed individuals of A. officinalis. A. officinalis seems to be very reactive to substrate-borne vibrations, unlike A. vulgare. This different reactivity might be related to a more complex defense mechanism developed as an evolutionary adaptation to the xeric environment, and/or to a means of communication mediated by substrate-borne vibrations, like in insects.