ROLE OF CAVE FEATURES FOR AQUATIC TROGLOBIONT FAUNA OCCURRENCE: EFFECTS ON “ACCIDENTALS” AND TROGLOMORPHIC ORGANISMS DISTRIBUTION

Subterranean aquatic habitats may be of particular interest from the zoological point of view. Most of the studies dealing with aquatic troglobiont fauna focus on troglobionts, such as organisms spending their entire life cycle in caves. Few studies are dedicated to non obligate cave dwellers whose occurrence is usually considered as accidental or random. The focus of this paper is on identifying the role played by cave features in the occurrence of aquatic troglobiont fauna and assessing the relationship between species with and without troglomorphic features and their cave habitat requirements. Organisms’ occurrence and environmental features were assessed during a repeated survey of all the caves occurring in a karstic valley of north-western Italy. We surveyed 39 natural caves from March to December 2013 sampling the waterbodies inside them for fire salamander larvae and invertebrates occurrence. 11 aquatic taxa were recorded during this study including 2 aquatic troglobiont species, Niphargus ambulator Karaman, 1975 and Dendrocoelum sp. n. All the taxa did not occur randomly. Aquatic troglobionts preferred deep and dark caves while other non obligate cave dweller occurred in shallower and brighter caves. The most important variables assessing distribution within caves were distance from the entrance and the temperature variation range of the pools. The occurrence of troglomorphic organisms was positively affected by pool distance from the cave entrance and pool area

Think of what lies below, not only of what is visible above, or: a comprehensive zoological study of invertebrate communities of spring habitats

Springs are interface habitats between the surface and subterranean environments, often neglected by zoological studies and generally regarded only from a surface perspective. Springs are also often collected and managed by humans: catching buildings that collect spring water may provide an accessible window over groundwaters. With this paper, we aim to assess the determinants of invertebrates' occurrence in springs using a comprehensive approach and considering the role of catching buildings and of predator occurrence. During 2017 and 2018, we performed six repeated surveys in 44 springs of N-Italy. We distinguished between collected and natural springs, assessed the springs morphological features and recorded the occurrence of predator Salamandra salamandra (Linnaeus, 1758) larvae and of four invertebrate taxa corresponding to strictly spring-dwelling, groundwater-dwelling and stream-dwelling groups, such as the gastropod Graziana alpestris (Frauenfeld, 1863), the amphipods Niphargus thuringius Schellenberg, 1934 and Gammarus balcanicus Schäferna, 1922 and dipterans larvae of the family Tipulidae. We used a constrained redundancy analysis to evaluate the relative role of fire salamander occurrence and of springs features on the occurrence of the invertebrate taxa surveyed. Spring typology and fire salamander larvae were the major determinants of spring invertebrates' occurrence. G. alpestris was positively related to artificial catching structures. Fire salamander was related to the occurrence of N. thuringius, G. balcanicus and Tipulidae larvae. Our results provide evidence that catching spring structures can significantly favour the detection of strictly spring-dwelling species; moreover, we reveal that the breeding of semi-aquatic predators like salamanders may play important roles on the community of invertebrates occurring in the spring habitats

Thirty years of invasion: the distribution of the invasive crayfish Procambarus clarkii in Italy

The presence of the red swamp crayfish Procambarus clarkii in Italy is documented since 1989, but no comprehensive data are available on its spread through time at the national scale. New confirmed records for Procambarus clarkii are continuously arising in recent years across the country. By reviewing the scientific and grey literature, we obtained an up-to-date map of the species invasion in Italy. This information can help to monitor and understand the spread of this highly invasive crayfish and to implement more effective management measures.

Intérêt écologique des galeries de drainage

Artificial subterranean habitats can be of important ecological interest. Draining galleries are a typology of artificial springs with underground development characterized by an almost horizontal tunnel that penetrates the side of a slope, to catch the subterranean water and bring it outward. They are a very ancient spring catching technique and provide interesting unstudied subterranean habitats. In this study we surveyed 18 draining galleries in NW Italy. We provide specific environmental data that can help to support broad conclusions on the ecological features and value of these habitats. We found that they house permanent waterbodies, have lengths up to 120 m, are characterized by climatic conditions similar to those of natural caves. We collected several taxa of organisms, adapted to subterranean life as well as coming from outside environment, which find inside draining galleries shelter, roosting and breeding sites. We tested the role of accessibility in determining galleries biodiversity and we found that the latter is scarcely affected. From a conservationist point of view draining galleries can have important ecological value, particularly in areas devoid of natural subterranean habitatsLes environnements souterrains artificiels peuvent être très intéressants d'une point de vue écologique. Les galeries drainantes sont des sources artificielles avec un développement hypogé constitué par une galerie presque horizontale qui s'étend à l'intérieur d'un relief. Il s'agit d'une technique de captage très ancienne qui a créé des habitats souterrains non ou peu étudiés et qui sont potentiellement très intéressants d'un point de vue écologique. Nous avons étudié 18 galeries drainantes dans le nord-ouest de l'Italie. Nous présentons des données écologiques spécifiques qui peuvent aider à formuler des conclusions générales sur les caractéristiques écologiques de ces habitats hypogés. Les galeries drainantes, qui dans la région d'étude atteignent 120 m de longueur, offrent la présence de biotopes humides permanents et ont des caractéristiques climatiques semblables à celles des grottes. Elles constituent des refuges et des sites de reproduction tant à des organismes typiques de la faune cavernicole qu'à beaucoup de taxons provenant de l'extérieur. Nous n'avons pas observé d'influence statistiquement significative de l'accessibilité des sites sur leur niveau de biodiversité. Du point de vue de la conservation les galeries de drainage présentent une valeur écologique certaine, surtout dans les zones dépourvues d'environnements souterrains naturels

Le rôle des caractères du cours d’eau et de la structure du paysage sur la distribution des triclades dans le haut des cours d’eau : l’exemple de Polycelis felina

Le triclade Polycelis felina est un taxon intéressant par son rôle de bioindicateur important dans les cours d'eau et les petits environnements lotiques. Des informations ont été recueillies sur sa distribution dans les cours d'eau de la partie sud de la province de Lecco (N Italie) afin d'obtenir une image claire de ses préférences biologiques et écologiques et des particularités des biotopes dans lesquels on le trouve. Au total 194 sites sur 110 cours d'eau ont été prospectés durant la campagne de terrain menée en 2005 et 2006. Des populations de P. felina furent trouvées dans 26 % des sites visités. Les rôles respectifs, quant à la présence de P. felina, de la morphologie naturelle du cours d'eau, de la qualité de l'eau, et d'autres facteurs (tels la présence d'autres triclades, d'écrevisses et de larves de Salamandra salamandra) ont été analysés

Fire salamander (Salamandra salamandra) males’ activity during breeding season: effects of microhabitat features and body size

After metamorphosis, fire salamander is considered fully terrestrial, usually inhabiting wooded areas around aquatic habitats. It is often reported that only females go back to water for laying the larvae. The aim of this study is to assess if sites where males are active during the breeding seasons have specific features among microhabitat determinants and distance from the breeding sites. In the autumns of 2013 and 2014, we surveyed 26 transects and 72 plots around six isolated breeding sites in North-Western Italy. During rainy nights, we recorded males position and distance from breeding pools, while during daytime we characterized the environmental features of the plots. Males detection probability was relatively high (mean ± SE: 81.0 ± 4.3%). Several males (15% of the observations) were encountered inside breeding pools where females were laying larvae. Males occurrence was positively related to plots closer to breeding pools and higher leaf litter depth. Larger males were found closer to the breeding pools. This case study shows that the distribution of fire salamander males during the breeding season depends on the breeding sites.

First record of a male-male aggressive interaction in the golden Alpine salamander Salamandra atra aurorae (Caudata, Salamandridae)

The golden Alpine salamander Salamandra atra aurorae Trevisan, 1982 is an endemic subspecies found in Sette Comuni and Vezzena plateau in Veneto, Italy. We describe an aggressive interaction between two males which fought for four minutes, trying to go on top of each other and rubbing their chin on the antagonist’s head. This is the first documented case of aggressive behaviour in Salamandra atra aurorae

Don’t forget the vertical dimension: assessment of distributional dynamics of cave-dwelling invertebrates in both ground and parietal microhabitats

Biological studies on factors shaping underground communities are poor, especially those considering simultaneously organisms with different degrees of adaptation to cave life. In this study, we assessed the annual dynamics and use of both horizontal and vertical microhabitats of a whole community with the aim of understanding whether cave-dwelling organisms have a similar distribution among vertical and ground-level microhabitats and to find out which microhabitat features influence such distribution. We monthly assessed from 2017 to 2018, by direct observation combined with quadrat sampling method on the ground and transects on the walls, richness and abundance of 62 cave-dwelling species in a cave of Northern Italy. Environmental factors such as light intensity, temperature, relative humidity and mineralogical composition of the substrates were measured during each monitoring session, influencing the dynamics of the whole community and revealing significant differences between ground and wall microhabitats. A gradient of variation of the species assemblages occurred from the entrance toward inner areas, however, evidence that the dynamics of the walls are very different from those occurring at the ground independent from the distance from the surface are shown. Biodiversity indices highlighted sampling area diversity and a discrete total cave fauna biodiversity with the highest values found near the entrance and the lowest in the inner part of the cave

Un morso di più: ecologia del cannibalismo in Salamandra salamandra

peer reviewe

miR-7 Knockdown by Peptide Nucleic Acids in the Ascidian Ciona intestinalis

Peptide Nucleic Acids (PNAs) are synthetic mimics of natural oligonucleotides, which bind complementary DNA/RNA strands with high sequence specificity. They display numerous advantages, but in vivo applications are still rare. One of the main drawbacks of PNAs application is the poor cellular uptake that could be overcome by using experimental models, in which microinjection techniques allow direct delivery of molecules into eggs. Thus, in this communication, we investigated PNAs efficiency in miR-7 downregulation and compared its effects with those obtained with the commercially available antisense molecule, Antagomir (Dharmacon) in the ascidian Ciona intestinalis. Ascidians are marine invertebrates closely related to vertebrates, in which PNA techniques have not been applied yet. Our results suggested that anti-miR-7 PNAs were able to reach their specific targets in the developing ascidian embryos with high efficiency, as the same effects were obtained with both PNA and Antagomir. To the best of our knowledge, this is the first evidence that unmodified PNAs can be applied in in vivo knockdown strategies when directly injected into eggs