4 research outputs found
Helminth biocoenosis of Lepus europaeus meridiei (Hilzheimer, 1906) from Pianosa island, Italy
No full textPianosa is a 10 km(2) Italian island in the Tyrrhenian Sea which is part of the Tuscan Archipelago National Park. In this island lives a brown hare population which, according to the literature, belongs to the ancestral taxon Lepus europaeus meridei that offers a unique opportunity to observe how the parasite biocoenosis shapes in condition of isolation, limited space availability and high population density. The aim of this work is to describe the helminth component community of a non-managed, isolated, and dense hare population, evaluating host-parasite relationship and parasite community structure. All 26 analyzed hares (13 males and 13 females) were in good physical conditions, and all of them harboured exclusively the nematode Protostrongylus oryctolagi only. This is the first report of this lungworm species in Italy. The estimated overall abundance was 48.15 worms per examined hare (range 3–258, median 50) and the parasites were unevenly distributed across host population, with few hosts having most parasites (aggregated or overdispersed distribution). No significant relationship was detected between the number of isolated parasites and hare sex and weigh. The effect of the isolation of Pianosa's hare population seems to have acted reducing parasite richness, while the high host density is probably the cause of the high prevalence and abundance of the single helminth species collected. In conclusion, despite the low impact of parasites confirmed also by the overdispersed parasite distribution, the low diversity of the studied parasite community sounds a warning for the management of the hare population and the whole Pianosa's ecosystem
Acquacoltura di specie emergenti: Genotipizzazione e pedigree in Anguilla anguilla, primi risultati.
No full textAbstract - Anguilla anguilla (Linnaeus, 1758) is a critically endangered species, whose existence in the wild is highly threatened by human activities and is included in the IUCN Red List of threatened species as “Critically Endangered”. Restocking and captive breeding programs designed to preserve the residual genetic variability should represent the future for conservation of this species. In this perspective, the present study aims to increase the knowledge about the mechanisms at the basis of reproduction of the European eel in semi-natural conditions, through paternity assignment. Here we show the very first parental assignment results of a plenty successful reproductive event that occurred in 2016: four families of European eel founded by four female plus 11 males in different mixes and their progeny, for a total of 206 samples. Parental allocations revealed the presence of different percentage of success of males in fertilizing eggs, with two “super-males” at the top of the productivity, with the 19.9% and 18.8% of total larvae (males 128 and 129) and two “weak-males” at the end of the distribution of productivity curve (males 134 and 135). Since the artificial reproduction of European eel is a very challenging topic for world aquaculture, these first results may help in drawing future breeding plans aimed both to increase the productivity for human consumption and to develop restocking plans in order to try to reduce the speed of decreasing in worldwide stocks of European eels
Sexual behaviour and reproductive performance of the endangered European eel Anguilla anguilla (Linnaeus, 1758) based on direct observationsand paternity assignment in semi-natural conditions
No full textEuropean eel Anguilla anguilla is among the highly valued species for aquaculture. Since its peculiar biology, it is not yet possible to complete the whole life cycle in artificial conditions and its supply depends entirely on wild catches. In the last 50 years this species has suffered a population reduction of 99 % mainly due to overfishing. In a conservation perspective, it is of fundamental importance to improve the aquaculture production of European eel, to avoid the extinction of this species and preserve its residual genetic variability, allowing at the same time the fulfilling of costumers request without increasing its harvesting pressure. In this study we aimed to deepen the knowledge about the mechanisms at the basis of reproduction of the European eel in semi-natural conditions, through direct observation of spawning behaviour and through the paternity assignment using microsatellite markers. The systematic and prolonged observation of the reproductive behaviour of European eel and the contextual parentage analyses we carried out for the very first time in this species on 39 adults and 432 F1 randomly collected. We contributed to unravel the sexual behaviour of this species in the most common artificial reproduction conditions (polyandry), and define the precise courtship sequence until the release of gametes, and the male-male hierarchy in courtship. We characterized for the first time three main types of male: dominant (the first who starts the courtship, and the one with the majority of F1 assigned), subordinate (which starts the courtship only in a second time and with a minor percentage of F1 ascribed) and ineffective (which sometime appears totally disinterested to courtship and has few F1 or none). The evidences here produced represent an important attempt for developing good reproduction practices of the critically endangered European eel, providing a good starting point for its future aquaculture production
Protostrongylids nematodes as a tool to study the biogeography of wild mammals
No full textThe European brown hare (Lepus europaeus Pallas, 1778) is an important game species, distributed across Europe and introduced in other regions. Recently, a geographically isolated population, closely related to an ancestral lineage of Lepus europaeus meridiei, was found on Pianosa Island, off the coast of Tuscany, Italy (Mengoni et al., 2018). Thus, the unique opportunity to explore the evolution and genetic structure of its helminth parasites was added to its exceptional isolation condition.
Various lungworm species within the genus Protostrongylus (Nematoda: Protostrongylidae) are described in European brown hares.
Our aim was to analyze the parasite population through morphological and molecular approaches in order to study the biogeography of the European brown hares (L. e. meridiei) population from Pianosa Island. Moreover, we investigated the morphology of a monospecific genus, i.e. Orthostrongylus, considering its quite intrigant descriptive history and its still unclear and debated classification.
Nuclear and mitochondrial markers were used based on their resolution power and expected polymorphism; the whole Internal Transcribed Spacer 1 and 2 (ITS), including the 5.8S rRNA sequence and the Large Subunit (28S) were used, as nuclear genes, for confirmation of the species identification. Conversely, the cytochrome oxidase c subunit I (COI) was used, as mithocondrial genes, to assess interspecific genetic relationships.
Molecular analysis corroborated the morphological identification since all the generated ITS and LSU sequences were 100% consistent with the species Protostrongylus oryctolagi and Orthostrongylus macrotis.
The paucity of molecular data existent about this genus of parasites underlines the need for more insight’s studies. An in-depth analysis of broncho-pulmonary parasites and the host-parasites relationships along with the improvement of the use of mitochondrial genes, as well as the assessment of new polymorphic markers could contribute to an extensive understanding of parasites fauna and taxonomy, as well as their relationship with wild mammals’ hosts
