Behavioral response of Biomphalaria glabrataexposed to a sublethal concentration of Euphorbia miliivar. hislopii latex

Abstract

The Euphobia milii var. hislopii latex has been tested in the control of schistosomiasis but its action in the locomotor activity of Biomphalaria glabrata is unknown. The objective of this work was to study the locomotor and reproductive behaviors of B. glabrata exposed to E. milii var. hislopii latex. For this, 96 snails were individually exposed to the latex (LC 50-0.53 mg / L) for 24 hours. The specimens were submitted to biomonitoring for image analysis to record the locomotor parameters at different times: before exposure (control), one day post exposure (group 1 d-p-e) and 30 days post exposure (group 30 d-p-e). The reproductive parameters were recorded weekly for 10 weeks. All locomotor activities of group 1 d-p-e decreased significantly. The egg/egg mass ratio decreased the week after exposure while there was an increase in the hatching rate. After 30 days, these reproductive parameters were similar to those observed in these same snails before exposure. However, the number of hatched snails declined after exposure until the end of the experiment. The influence of the latex in the parameters of B. glabrata added further evidence that this natural water-soluble product can be an important tool for the control of schistosomiasis.

Reproductive alterations of Biomphalaria glabrata (Say, 1818) infected with Angiostrongylus cantonensis (Chen, 1935) and exposed to Euphorbia milii var. hislopii latex

“…Among the many forms of modulation exerted by stressors in snails, the most common are total and partial castration, reproductive compensation and increase in mortality (Minchella and Loverde, 1981;Mello-Silva et al, 2007;Faro et al, 2013;Alberto-Silva et al, 2015, 2020. All of these events were observed in our study to a greater or lesser degree.…”

“…Alberto- Silva et al (2020), evaluating the reproductive and locomotor parameters of B. glabrata when exposed to the LC 50 (0.53 mg/L) of E. milii var. hislopii latex, also observed a significant reduction in the number of eggs and egg masses in the first week after exposure, followed by a return to normal oviposition patterns.…”

“…They were identified and transferred to Petri dishes containing 10 ml of dechlorinated water, kept at a controlled temperature of 25° C ± 2 °C, with 12/12 photoperiod. The number of hatched snails was counted 15 days later, as described by Alberto- Silva et al (2020). The snails were fed ad libitum with fresh lettuce leaves (Lactuca sativa L.) three times a week, and all experiments carried out in triplicate.…”

“…Helminth infection and exposure to phytochemicals are known to modulate the survival and reproductive parameters of intermediate host snails (Moore, 2002;Oliveira-Filho et al, 2014;Alberto-Silva et al, 2015, 2020. Infection can cause partial or total disruption of oviposition and egg hatching, in addition to biochemical and histopathological changes, leading to a reduction in the population of infected snails (Faro et al, 2013;Guerino et al, 2017).…”

“…hislopii has been studied for its schistosomostatic (Augusto et al, 2017) and molluscicidal properties related to survival and reproductive parameters of snails such as Achatina fulica (Ferussac, 1821) (Crignis et al, 2012), Leptinaria unilamellata D'Orbigny, 1835 (Afonso-Neto et al, 2010), Bulimulus tenuissimus (D'Orbigny, 1935) (Patrício et al, 2019), Lymnaea columella (Say, 1817) Amorim, 2003) andB. glabrata (Mello-Silva et al, 2007;Lima, 2010;Alberto-Silva et al, 2020). This phytochemical presents several advantages, such as biodegradability, low cost, efficiency in sublethal doses (less than 2.0 mg/L) (Vasconcellos and Schall, 1986) and selective effect on infected snails.…”