Search results for "Copepoda"

Cooking infected copepods: On the survival of Guinea worm larvae

2020

The microcrustacean fauna of Sicily and the Central Mediterranean Sea area - Current knowledge and gaps to be filled

2006

The current knowledge of freshwater entomostracans from Sicily and some neighbouring central-Mediterranean countries is briefly reviewed. Data concerning different countries and different taxonomical groups are markedly inhomogeneous and often far from being representative of the real biota of the corresponding countries. This gap prevents a sound biogeographical analysis of the freshwater microcrustacean fauna of the area. The major gaps that have to be filled are highlighted and the need for more surveys and monitoring is emphasised.

Cryptic species within the freshwater copepod genus Hemidiaptomus (calanoida, diaptomidae).

2009

The copepod genus Hemidiaptomus is composed by about 17 large-bodied species inhabiting the freshwater temporary water bodies of the whole Palaearctic region. It currently comprises three subgenera, which are mostly parapatric and present only limited co-occurrence areas. There is no consensus on the taxonomical arrangement of the entire group, and to date no molecular studies have been carried out to test it. Accordingly, a thorough revision of the entire genus using a combined morphological and molecular approach is strongly advisable. We have thus decided to investigate the pattern of morphological and molecular diversity of three species of the genus Hemidiaptomus belonging to the three…

Sicilian Temporary Ponds: An Overview of the Composition and Affinities of their Crustacean Biota

2009

Available data on Sicilian entomostracans allowed an initial characterization of the freshwater crustacean biota of the island and to formulate some hypotheses on its origin.The absence of supra-specific endemic taxa and the current regional distriburion of the investigated species suggest a late Pleistocene colonisation of the island by temperate taxa with a northern affinity, currently confined to the coolest areas of the island, followed by a Holocene arrival of thermophilous species coming from the Maghreb, which is still in progress. The importance of Sicily as a "crossroad" for the faunas of the circum-Mediterranean countries is thus confirmed.Unfortunately, and in spite of the EU dir…

Morphological Similarity and Ecological Overlap in Two Rotifer Species

2013

Co-occurrence of cryptic species raises theoretically relevant questions regarding their coexistence and ecological similarity. Given their great morphological similitude and close phylogenetic relationship (i.e., niche retention), these species will have similar ecological requirements and are expected to have strong competitive interactions. This raises the problem of finding the mechanisms that may explain the coexistence of cryptic species and challenges the conventional view of coexistence based on niche differentiation. The cryptic species complex of the rotifer Brachionus plicatilis is an excellent model to study these questions and to test hypotheses regarding ecological differentia…

Long-lasting effect of stress on susceptibility of a freshwater clam to copepod parasitism.

2005

The question whether a stress event can have a long-lasting effect on susceptibility to parasites was studied using a freshwater bivalve clam and its crustacean parasite as a model system. Anodonta piscinalis clams were collected from 2 populations during August–September 2002. Clams were transported to the laboratory and marked. The stressed clams were subjected to low oxygen for 25 days, while the unstressed control clams were caged in their lakes of origin for the same period. Then the clams were transported to a third lake where they were exposed to natural infections by the ergasilid copepod, Paraergasilus rylovi , 11 months after the stress event. The stressed clams were more intensiv…

Salmon lice in the Pacific Ocean show evidence of evolved resistance to parasiticide treatment

2022

AbstractParasitic salmon lice (Lepeophtheirus salmonis) threaten the economic and ecological sustainability of salmon farming, and their evolved resistance to treatment with emamectin benzoate (EMB) has been a major problem for salmon farming in the Atlantic Ocean. In contrast, the Pacific Ocean, where wild salmon are far more abundant, has not seen widespread evolution of EMB-resistant lice. Here, we use EMB bioassays and counts of lice on farms from the Broughton Archipelago, Canada—a core region of salmon farming in the Pacific—to show that EMB sensitivity has dramatically decreased since 2010, concurrent with marked decrease in the field efficacy of EMB treatments. Notably, these bioass…

Responses of zooplankton to cane sugar additions to a small humic lake, Alinen Mustajärvi

2010

The response to projected increase in dissolved organic carbon (DOC) loading to boreal lakes is being studied in lake Alinen Mustajärvi, a small humic lake in southern Finland, where labile DOC concentration has been artificially increased during 2008 and 2009 by monthly additions of cane sugar. As part of this wider project, in this thesis the responses of the zooplankton community to cane sugar addition were studied. Zooplankton samples were collected monthly in the ice-free periods of 2007, 2008 and 2009 and the mean densities and mean carbon biomasses of rotifers and crustacean zooplankton (cladocerans and copepods) were calculated. Stable isotope analyses (δ13C and δ15N) were made for …