In the Laboratory of Parasites of Fishes, Crustaceans and Mollusks (CEPAVE), we undertook a parasitological study on three species of fish from the Espinal and Esteros del Iberá ecoregions of Argentina. Clinostomid metacercariae were found parasitizing Characidium rachovii, Crenicichla vittata and Gymnogeophagus balzanii. In this study, we analysed the damage that these parasites inflict on their hosts through the evaluation of histological sections. In addition, Clinostomum metacercariae were identified using morphological characters and DNA barcoding. In the pathological analysis, we observed that muscle tissue was the most affected. The inflammatory response showed vascular congestion areas and infiltration of numerous inflammatory cells, mainly lymphocytes. The molecular and morphological approach supports the presence of three new lineages of clinostomid metacercariae in Argentina. This could lead to the discovery of a high number of lineages or species of Clinostomum from South America.

Carabid beetles and spiders are at the top of the hierarchy of general invertebrate predators, which can help to reduce the abundance of harmful forest pests. They are also frequently used as environmental indicators. In this paper we analyzed the abundance, species richness and changes in carabid beetle and spider assemblages in three treatments of pine forest regeneration -natural, natural with soil prepared by ploughing and artificial with seedlings planted in ploughed soil. The most beneficial forest regeneration treatment variant of forest regeneration for carabid beetles and spiders was the natural regeneration of pine stands without any preceding soil preparation. Both taxa responded strongly to soil ploughing. We also noted the replacement of forest species by less sensitive open area species. In carabid assemblages, large changes in the trophic structure were observed, as predatory species were replaced by hemizoophages in the ploughed treatments.

Spiders (Araneae) create abundant and diverse assemblages in many agroecosystems, where they play a crucial role as the main group of predators and pest controllers. However, seasonal disturbance in the agricultural environment (e.g., harvesting or ploughing) affects spider assemblages. The main aim of this research was to compare assemblages of Araneae colonising cereal fields cultivated under two different systems of soil tillage: conventional with ploughing and non-inversion tillage. The research covered plantations of triticale, wheat, and barley, situated in northeastern Poland. Ground-dwelling spiders were captured into modified pitfall traps filled up to 1/3 height with an ethylene glycol solution. In total, 6744 spiders representing 67 species classified in 13 families were caught. The traps were emptied every two weeks from the end of April until the end of July. A total of 2410 specimens representing 55 species were captured in the fields with simplified cultivation, while the remaining 4334 specimens representing 49 species were trapped in conventional fields where ploughing was performed. The Shannon diversity (H’) and evenness (J’) indices reached higher values in the fields without ploughing. According to IndVal Erigone, dentipalpis and Bathyphantes gracilis were signifi-cantly characteristic (p < 0.05) for non-inversion soil tillage, whereas six species, Oedothorax apicatus, Pardosa prativaga, Pardosa paludicola, Pachygnatha clerki, Dicimbium nigrum brevisetosum, and Clubiona reclusa, were typical of soil tillage with ploughing. The research showed that simplification of soil tillage in cereal fields improves the biodiversity of arachnofauna in agricultural ecosystems. The use of conventional tillage systems with ploughing promotes agrobiontic species of the families Linyphiidae and Lycosidae.

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