Mu opioid receptor in spermatozoa,eggs and larvae of gilthead sea bream (Sparus Aurata) and its involvement in stress related to aquaculture

In aquaculture, unfavourable conditions experienced during early development may have strong downstream effects on the adult phenotype and fitness. Sensitivity to stress, leading to disease, reduced growth and mortality, is higher in larvae than in adult fish. In this study, conducted on sea bream (Sparus aurata), we evidenced the presence of the mu opioid receptor in gametes and larvae at different developmental stages. Moreover, we evaluated the possibility of reducing the effects of artificially produced stress, altering temperature, salinity and pH, by naloxone (an opioid antagonist) and calcium. Results evidenced that mu opioid receptor is present in larvae and in gametes of both sexes and that, during larval growth, its expression level changes accordingly; furthermore, naloxone/calcium association is efficacious in increasing the survival period of treated larvae compared to controls. We conclude that in sea bream rearing, the use of naloxone/calcium against stress can improve fish farming techniques by reducing larval mortality and consequently increasing productivity.     

Alien scale insects (Hemiptera Coccoidea) in European and Mediterranean countries: the fate of new and old introductions

This contribution focuses on recent interceptions and introductions of alien scale insects and their current distribution in European and Mediterranean countries. Data and collections were gathered in markets, nurseries, and botanical gardens, mostly in Italy, either indoors or outdoors. New or recent records of the following alien species are presented: Exallomochlus hispidus (Morrison); Ferrisia virgata (Cockerell) (Pseudococcidae); Coccus viridis (Green); Milviscutulus mangiferae (Green) (Coccidae); Aonidiella orientalis (Newstead); Aspidiotus destructor Signoret; Aulacaspis tubercularis Newstead; Fiorinia fioriniae Targioni Tozzetti; Lepidosaphes pinnaeformis (Bouché); Pseudaulacaspis brimblecombei Williams (Diaspididae). New data and pest status of Phoenicococcus marlatti Cockerell (Phoenicococcidae) and Trabutina mannipara (Hemprich & Ehrenberg) (Pseudococcidae) are also reported. The possible repeated introductions of the latter from North Africa to south Italy by trans-Mediterranean winds, is hypothesized.     

A novel type of seaweed extract as a natural alternative to the use of iron chelates in strawberry production

The new generation of seaweed extracts, such as Actiwave^®, may represent a promising strategy to reduce the use of phytochemicals in agriculture. Actiwave^® is a metabolic enhancer derived by the algae Ascophillum nodosum, but differently from some older seaweed extracts, it has a constant and balanced formulation containing kahydrin, alginic acid and betaines which synergistically contribute to the efficacy of the product. Actiwave^® has been proposed to increase the mineral nutrient uptake and the abiotic stress tolerance. The aim of this work was to evaluate, under a multidisciplinary approach, the effect of the biostimulant on the vegetative and productive performances of strawberry plants grown on a lime inducing iron chlorosis substrate. This biostimulant increased the vegetative growth (10%), the leaf chlorophyll content (11%), the stomata density (6.5%), the photosynthetic rate and the fruit production (27%) and berry weight. The most significant result was the increase of the plant biomass: the shoot dry matter was increased up to 27% and root dry matter up to 76%. Finally, preliminary experiments showed that Actiwave^® positively influenced also the root-associated microbial biocoenosis. These results are discussed in relation to the physiological and ecological mechanisms proposed to explain the beneficial effects of this seaweed extract. Finally, the effects of Actiwave^® and sequestrene were significantly similar, thus showing that this biostimulant may represent an environmental-friendly substitute of the iron chelates.     

Falling through the cracks: the fading history of a large iconic predator

Human impact on the oceans predates scientific observation, which for many animal populations has captured only recent changes. Such a limited knowledge can hamper finding optimal management and conservation strategies including setting appropriate recovery targets. Sawfishes are among the most endangered marine vertebrates in the ocean. Historical human impacts have resulted in sawfish extinction in many coastal areas around the world; however, in the Mediterranean Sea, their past presence and possible extinction have been debated for decades. Recently, it was concluded that the region never hosted resident populations because of unsuitable environmental conditions. Through an extensive bibliographic and archival search and an extinction analysis, we reconstructed the history of sawfishes in the Mediterranean Sea. Between 1576 and 1959, there were 48 independent accounts of the occurrence of two sawfish species (Pristis pristis, Pristidae and Pristis pectinata, Pristidae), including 24 documented catches. Sawfishes were mainly recorded in the western Mediterranean, in areas close to large rivers with light human impact. Most of the documented individuals were juveniles, suggesting local parturition. Extinction analyses yielded variable results and were affected by the sparseness of records but suggested that both species went extinct in the Mediterranean Sea in the 1960s–1970s. Our results challenge current assumptions on sawfish ecology and biogeography, offer new options for sawfish conservation in the Atlantic and highlight the importance of historical analyses for reconstructing ecosystem baselines and setting recovery targets.     

Hexapod origins: monophyletic or paraphyletic?

Recent morphological and molecular evidence has changed interpretations of arthropod phylogeny and evolution. Here we compare complete mitochondrial genomes to show that Collembola, a wingless group traditionally considered as basal to all insects, appears instead to constitute a separate evolutionary lineage that branched much earlier than the separation of many crustaceans and insects and independently adapted to life on land. Therefore, the taxon Hexapoda, as commonly defined to include all six-legged arthropods, is not monophyletic.