Preliminary phytochemical screening and molluscicidal activity of the aqueous extract of Bidens pilosa Linné (Asteraceae) in Subulina octona (Mollusca, Subulinidade).

The aim of this study was to establish reference concentrations (LC₅₀ e LC₉₀) of aqueous extracts of Bidens pilosa on the land snail Subulina octona, in order to assess the changes caused by 24 and 48 h exposure to the sublethal concentration regarding species' fecundity, hatchability and in offspring produced after exposure to confirm the presence of tannins, saponins and flavonoids in this plant species. Eggs newly hatched and 30 day-old snails were exposed to sublethal concentration, calculated for adults. The phytochemical analysis confirmed the presence of flavonoids, condensed tannins and saponins in the aqueous extract of B. pilosa. The LC₅₀ and LC₉₀ obtained were 51.4 mg/mL and 74.1 mg/mL respectively. The exposure to sublethal concentration reduced significantly the hatchability and the survival of the offspring hatched from exposed eggs and also caused a reduction on survival and growth in snails exposed for both time period. The exposure time also caused a reduction at the evaluated parameters.