Wyniki wyszukiwania - Biblioteka Nauki

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Daphniola Radoman, 1973 (Caenogastropoda: Truncatelloidea) at East Aegean Islands

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Szarowska M. , Hofman S. , Osikowski A. , Falniowski A.

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nr 4

EN

Shell habitus and COI mitochondrial gene sequences of one freshwater snail from Khios and three from Rhodes islands were analysed. Both methods confirmed assignment of these specimens to the genus Daphniola Radoman, 1973. Genetic distance between individuals from these two islands is surprisingly low, strongly suggesting that they belong to the same species, still undescribed. Comparison of COI sequences with other known species of this genus shows that the closest relative of the Khios and Rhodes populations is D. louisi Falniowski et Szarowska, 2000 from Attica. The results are discussed in the context of geological and climatic history of the Mediterranean.

2

Radix spp.: Identification of trematode intermediate hosts in the Czech Republic

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Hunova K. , Kasny M. , Hampl V. , Leontovyc R. , Kubena A. , Mikes L. , Horak P.

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tom 57

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nr 3

EN

Lymnaeid snails of the genus Radix serve as intermediate hosts of some schistosomes and fasciolids. In Europe, delineation of species within the genus Radix is unresolved and, therefore, spectrum of snail hosts susceptible to trematode infections is under discussion. We used and compared three criteria for species delineation using snails collected at 43 localities. (a) Sequence analysis of ITS-2 rDNA disclosed that the collected snails belong to four species — R. auricularia (Linnaeus, 1758), R. peregra (Müller, 1774), R. lagotis (Schrank, 1803) and R. labiata (Rossmaessler, 1835) (criteria and names are based on the work of Bargues et al. 2001). Occurrence of R. peregra in the Czech Republic was confirmed by molecular data for the first time. (b) Characterization of reproductive system disclosed differences in location, size and shape of bursa copulatrix and its ductus. Unfortunately, some R. labiata specimens shared morphological features of reproductive organs with R. lagotis. (c) Statistical analysis of shell morphology proved that significant differences exist among particular species. One prediction model showed that correct classification of species may be achieved in 82-84% of cases. However, identification of individual snails in the field (without knowledge of respective snail population and use of statistical tools) still remains a complicated issue due to overlaps of shell characteristics. Concerning the role in trematode transmission, R. lagotis, R. labiata and R. peregra are susceptible to Trichobilharzia regenti. Also, successful experimental infections of R. lagotis and R. labiata by Fascioloides magna were accomplished.

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Physicochemical changes and abundance of freshwater snails in Anambra River (Nigeria) during the rainy season

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Okoye C. O. , Echude D. , Chiejina C. O. , Andong F. A. , Okoye K. C. , Ugwuja S. E. , Ezeonyejiaku C. D. , Eyo J.

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tom Vol. 29, nr 2

169--181

EN

Rapid diversification is a way of responding to environmental change for freshwater organisms. This work examined the physicochemical changes and abundance of freshwater snails in Anambra River (Nigeria) during the rainy season. Field studies were conducted fortnightly from June to August 2019 at three stations of the river namely: Otuocha (station I), Otunsugbe (station II), and Ukwubili (station III) about 8.35 kilometers apart from each other. A scoop net of 2 cm mesh size and handpicking was used to sample freshwater snails randomly and water samples were taken to the laboratory for physicochemical analysis. A total of 896 freshwater snails belonging to 6 species (Afropomus balanoidea, Pomacea maculata, Lymnea stagnalis, Lanistes ovum, Pila wernei, and Saulea vitrea) were collected. Pomacea maculata was the most dominant species with a relative abundance of 45.87 %, while Saulea vitrea was the least dominant species with a relative abundance of 2.34 %. There was a significant negative correlation between dissolved oxygen and Pomacea maculate (r = –0.877, p = 0.002) and a positive correlation between dissolved oxygen and Stagnalis lymnea (r = 0.840, p = 0.005). The diversity of species was highest at Otuocha (1.171) followed by Ukwubili (1.133) and Otunsugbe (0.856) with average mean temperatures of (23.1 ±0.1) °C, (27.30 ±0.00) °C, and (26.80 ±0.03) °C respectively. The distribution of freshwater snails was influenced by the physicochemical variability of Anambra River during the rainy season. Therefore, further studies for a longer time and different seasons to examine the impact of physicochemical changes on the snail distribution are encouraged.

4

The unique character of the Swietokrzyski region in the light of malacofaunistic studies

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Barga-Wieclawska J. A.

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nr 1

5

Ecology and dynamics of freshwater snail vectors of Shistosoma haematobium [Bilharz, 1852] in Ahoada local government area [Rivers State, Nigeria]

80%

Agi P. I.

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tom 38

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nr 1-2

EN

The snail vectors were more abundant in stagnant waters. Percentage occurrence of Bulinus globosus (Morelet) was 44.4% in ponds, 44.3% in borrow pits, and 37.5% in lakes, while the occurrence of Bulinus forskali (Ehr.) was 62.3% in borrow pits, 48.1% in ponds, and 40.6% in lakes. Snail reproduction occurred in all months of the year with peaks in June and November and troughs in February and September. Snail density was related to the bottom substratum: 81.9% on mud, 72.2% on concrete, 20.0% on sand and 7.6% on silt. Snail infection with Schistosoma was high between October and December. The medium-sized class was most infected.

PL

Ślimaki-nosiciele były liczniejsze w wodach stojących. Udział Bulinus globosus (Morelet) wynosił 44.4% w stawach, 44.3% w wyrobiskach i 37.5% w jeziorach, a Bulinus forskali (Ehr.) 62.3% w wyrobiskach, 48.1% w stawach i 40.6% w jeziorach. Rozród ślimaków trwał cały rok, maksima przypadały w czerwcu i listopadzie, a minima w lutym i wrześniu. Zagęszczenie było związane z typem dna: udział obu gatunków wynosił 81.9% na dnie mulistym, 72.2% na podłożu betonowym, 20.0% na piasku i 7.6% na dnie ilastym. Poziom zainfekowania schistosomą był wysoki od października do grudnia. Najsilniej zarażone były ślimaki średniej wielkości.