Biomphalaria tenagophila (Orbigny, 1835) (Mollusca): adaptation to desiccation and susceptibility to infection with Schistosoma mansoni Sambon, 1907

Abstract

Experiments were carried out to test the susceptibility of Biomphalaria tenagophila to the infection with strain SJ of Schistosoma mansoni in the F1, F2 and non-selected parental generation. The potential adaptation of B. tenagophila to desiccation, in healthy mollusks and those exposed to the larvae of S. mansoni of the F1, F2 and non-selected parental generations was also studied. The presence of mucus and soil, at the shell opening, protected the snails against desiccation, favoring survival. The healthy mollusks performed more attempts against desiccation than those exposed to the larvae of the parasite. The mortality rate, during desiccation, was higher among mollusks that remained buried and with the shell opening unobstructed. During the desiccation period the stage of development of the parasite was influenced by the weight loss and the survival of the snails. The longer the period of desiccation, the greater was the weight loss observed, abbreviating survival. The non-selected parental generation was more sensitive to desiccation than the F1 and F2 generations, both in healthy mollusks and in those exposed to S. mansoni larvae. Healthy mollusks were more resistant to desiccation than those exposed to the larvae of the S. mansoni. Desiccation did not interrupt the development of S. mansoni larvae in mollusks, causing a delay in the cercariae elimination. The susceptibility of B. tenagophila to the SJ strain of S. mansoni, in mollusks maintained in water during the larvae incubation period, was similar in all three generations.

A new species of Biomphalaria Preston, 1910 (Gastropoda, Planorbidae) from the Upper Cretaceous of Uruguay

“…This genus is indicative of several environmental parameters, being very useful in paleoecological reconstructions. The populations of Biomphalaria usually live in lentic, shallow and very low energy environments, such as temporary puddles, marshes and shallow lakes, commonly with abundant aquatic vegetation (Cridland, 1967;Pieri et al, 1980;Olazarri, 1981aOlazarri, , 1981bBonetto et al, 1982;Vianey-Liaud & Lancastre, 1986;Ohlweiler & Kawano, 2001, 2002De Francesco, 2010;Hassan et al, 2011;Cabrera et al, 2018). A new species is described herein for the limestones of the Upper Cretaceous Queguay Formation, Uruguay.…”