Gianandrea La Porta

Larval development of Libellula depressa (Odonata, Libellulidae) from pools in central Italy

Abstract The developmental stages of the larvae of Libellula depressa were investigated for three years in permanent freshwater pools in central Italy. Eleven instars (F‐0 ‐ F‐10) of L. depressa were discriminated by size and scatter plot. Scatter plots were constructed using the following measurements: labium length, head width, metafemur length, forewing‐pad length, and total larval body length. Prolarvae instar was derived by Dyars law. The mean growth rate coefficient values were about 0.77 for isometric parameters and 0.51 for the forewing‐pad allometric parameter. L. depressa appeared to be a ‘spring species’, as defined by Corbet, and the population we studied had a mainly semivoltine life history and, probably, a small proportion of the larvae a univoltine cycle. Eggs showed direct development.

Characterization of the Skin Microbiota in Italian Stream Frogs (Rana italica) Infected and Uninfected by a Cutaneous Parasitic Disease

In human and wildlife populations, the natural microbiota plays an important role in health maintenance and the prevention of emerging infectious diseases. In amphibians, infectious diseases have been closely associated with population decline and extinction worldwide. Skin symbiont communities have been suggested as one of the factors driving the different susceptibilities of amphibians to diseases. The activity of the skin microbiota of amphibians against fungal pathogens, such as Batrachochytrium dendrobatidis, has been examined extensively, whereas its protective role towards the cutaneous infectious diseases caused by Amphibiocystidium parasites has not yet been elucidated in detail. In the present study, we investigated, for the first time, the cutaneous microbiota of the Italian stream frog (Rana italica) and characterized the microbial assemblages of frogs uninfected and infected by Amphibiocystidium using the Illumina next-generation sequencing of 16S rRNA gene fragments. A total of 629 different OTUs belonging to 16 different phyla were detected. Bacterial populations shared by all individuals represented only one fifth of all OTUs and were dominated by a small number of OTUs. Statistical analyses based on Bray-Curtis distances showed that uninfected and infected specimens had distinct cutaneous bacterial community structures. Phylotypes belonging to the genera Janthinobacterium, Pseudomonas, and Flavobacterium were more abundant, and sometimes almost exclusively present, in uninfected than in infected specimens. These bacterial populations, known to exhibit antifungal activity in amphibians, may also play a role in protection against cutaneous infectious diseases caused by Amphibiocystidium parasites.

Effects of selenium supplemented diets on growth and condition indexes in juvenile red swamp crayfish, Procambarus clarkii.

Effects of selenium diets (Se, 0.3 and 1.2mgkg(-1)) on juvenile red swamp crayfish Procambarus clarkii were observed for eight weeks. Growth, condition factors and Se levels in exoskeleton and hepatopancreas for both sexes and diets were evaluated at three endpoints. The specific growth rate (SGR) showed a faster, but not statistically significant growth in Se exposed specimens. Se levels were higher in exoskeleton and hepatopancreas of both Se exposed males and females, when compared to controls. The abdomen-total weight relationship (Tw/B) showed no significant differences between Se exposed and control groups. A constant decline of HI values was recorded in both Se exposed sexes and the same trend was observed in control males. Se exposed females evidenced lower HI after 4 and 8 weeks when compared to controls. Therefore, evident reductions of the health indicator values HI suggested that selenium can deplete the hepatopancreas energy reserves, mainly in juvenile male crayfish.

Long-term changes in diet and trophic niche of the European wildcat (Felis silvestris silvestris) in Italy

Previous studies on the feeding habits of the European wildcat (Felis silvestris silvestris) have shown high variability in the diet and in the degree of trophic specialisation of this felid. In order to update and improve the knowledge about the feeding habits of this carnivore, its diet and trophic niche in Italy were examined based on the material collected in 1996–2003 and compared with data obtained in 1968–1987 and with those from literature concerning other European areas. The present study pointed out that in Italy, the European wildcat displayed a broad dietary spectrum. Rodents permanently constituted the main food category; however, the most consumed prey shifted from Cricetidae in the past to Muridae more recently. Through time, the felid has changed its main prey and exploited a greater number of food categories reducing the predominant consumption of some of them. These changes involved an increase of the diet diversity resulting in a widening of the trophic niche and an incomplete niche overlap between time periods. Long-term changes in diet and trophic niche of the European wildcat which were found in this study indicate high flexibility of its feeding habits. This was confirmed by a review of the relevant literature on wildcat diet in Europe, which highlights the ability of this felid to either specialise on different main food items or to widen its feeding spectrum depending on the availability of prey.

Short-term cadmium exposure induces stress responses in frog (Pelophylax bergeri) skin organ culture

There have been a few studies on the negative effects of pollutants on amphibian skin, the first structural barrier that interacts with the environment and its potential contaminants. In this study an ex vivo skin organ culture from the amphibian Pelophylax bergeri was used to evaluate cell stress responses induced by short-term exposure to cadmium (Cd), a toxic heavy metal known to be an environmental hazard to both humans and wildlife. Histopathological studies were carried out on skin explants using light microscopy and changes in the expression of stress proteins, such as Metallothionein (MT) and Heat shock proteins (HSPs), were investigated by Real-time RT-PCR. Results revealed that amphibian skin reacts to Cd-induced stress by activating biological responses such as morphological alterations and dose- and time-dependent induction of Mt and Hsp70 mRNA expression, suggesting their potential role as biomarkers of exposure to Cd. This work provides a basis for a better understanding of the tissue-specific responses of amphibian skin as a target organ to Cd exposure and its in vitro use for testing potentially harmful substances present in the environment.

A geographic distribution data set of biodiversity in Italian freshwaters

We present a data set on the biodiversity of Italian freshwaters, including lakeshores and riverbanks of natural (N=379: springs, streams and lakes) and artificial (N=11: fountains) sites. The data set belongs partly to the Italian Long Term Ecological Research network (LTER-Italy) and partly to LifeWatch, the European e-Science infrastructure for biodiversity and ecosystem research. The data included cover a time period corresponding to the last fifty years (1962-2014). They span a large number of taxa from prokaryotes and unicellular eukaryotes to vertebrates and plants, including taxa linked to the aquatic habitat in at least part of their life cycles (like immature stages of insects, amphibians, birds and vascular plants). The data set consists of 6463 occurrence data and distribution records for 1738 species. The complete data set is available in csv file format via the LifeWatch Service Centre.

Airborne bacteria and persistent organic pollutants associated with an intense Saharan dust event in the Central Mediterranean

In this paper, we present a comprehensive taxonomic survey of the bacterial community and accurate quantification of polycyclic aromatic hydrocarbons (PAHs) associated with an intense Saharan dust advection, which impacted Central Mediterranean area in the whole 2014-2015 period. This work is part of an intensive field campaign at the EMEP regional background site of Monte Martano (Central Italy), considered well representative of long-range transport in the Central Mediterranean area. 22 samples have been characterized in their provenance region and have been considered for the chemical and biological characterization. The event described in the present paper was exceptionally intense at the sampling site allowing a detailed evaluation of the dust load on a regional scale, an estimation of the impact of PAH based on the Toxic Equivalency Factor methodology and a thorough characterization of the airborne bacterial fraction performed by High Throughput Sequencing approach. Afterward, we cultured viable bacteria and evaluated several enzymatic activities and conducted UV survival tests. Principal findings include: (i) the striking evidence that, during the Saharan dust event, a highly diverse and abundant bacterial community was associated with PAH concentrations higher than the yearly mean; (ii) the tangible presence of cultivable microbes; (iii) the proof that the isolates recovered from Saharan dust had the potential to be metabolically active and that almost all of them were able to persist following UV radiation exposure. Comparisons of results for the present case study with mean values for the 2014-2015 experimental campaign are presented. The bacterial community and chemical speciation associated with the Saharan dust advection were specific and very different from those associated with other air masses. The particular case of North-Western Atlantic, which represents one of the most typical advection route reaching the sampling site is discussed in detail.

Ecology and conservation of the Mediterranean trout in the central Apennines (Italy)

The Mediterranean brown trout is one of the freshwater fish species complex at greater risk of extinction in the Mediterranean area. The introduction of alien invasive species and their interaction with the native fauna represent some of the major threats to the survival of this species. Currently, the genetic variability of the Mediterranean trout is being compromised by the introgressive hybridization with the Atlantic trout (Salmo trutta Linnaeus, 1758). Therefore, it is necessary to gain further knowledge on genetic and demographic characteristics of Mediterranean trout populations, that, combined with environmental and angling data, will allow to undertake sound conservation strategies. The aims of the present study were to analyze: i) the demographic characteristics of the Mediterranean trout in seven central Apennine river basins where native populations are threatened by stocking with the domestic trout of north Atlantic origin; ii) the influence of both environmental parameters and different fishery management strategies on the status of native trout populations. The project focuses on 14 sites included in the Natura 2000 EU wide network of nature protection areas, established under the 1992 Habitat Directive. A total of 25 watercourses were investigated for a total of 32 sampling sites. A census of the fish fauna was carried out by electrofishing at each sampling location. Fish and environmental data were collected in spring and autumn 2014. The results obtained in the present research allowed us to detect the presence of three residual Mediterranean trout populations with a high degree of genetic integrity in the study area. The native trout populations were characterized by higher abundances and higher adult density values. Well-structured native populations with higher legal-size specimens density and poor body conditions in terms of relative weight were observed in the no-fishing areas, probably due to the presence of intraspecific competition phenomena. The environmental analysis confirmed the key role played by the geological characteristics of the central Apennines in shaping the introgression levels observed in the wild trout populations, while the recovery of the water quality appears decisive in the development of management strategies aimed at their conservation. Corresponding author: antonella.carosi@unipg.it