Evaluation of the feeding preference between the aquatic macrophytes Egeria densa and Chara indica by the invasive mollusk Melanoides tuberculata

Abstract

This study evaluated the feeding preference of the invasive mollusk Melaniudes tuberculata between the aquatic macrophytes Egeria densa and Chara indica. The experiment consisted of twelve experimental units (glass aquariums) each of which contained three liters of water and three compartments. Fragments of E. densa and C. indica were placed in separate compartments within each unit; the third compartment, which did not contain macrophytes, was used as the control. Twenty Melanoides tuberculata individuals were placed in each unit and monitored hourly over the course of 24 hours for preferential movements. Physical and chemical water variables were measured at the beginning and end of the experiment. Habitat complexity was determined through collected macrophyte fragments and determined using the Fractop program. After 24 hours, the highest average number of individuals was observed in the treatment with Chara indica (ten individuals), which differed significantly from the treatment with E. densa (four individuals) and the control treatment (two individuals). The number of individuals between the E. densa and control treatment were similar. M. tuberculata showed a clear feeding preference for C. indica.Keywords: habitat structure, gastropod, laboratory experiment. Avaliação da preferência do molusco invasor

INVASION OF THE THIARID SNAIL Melanoides tuberculata (MOLLUSCA) IN A CONSERVATION AREA OF THE SEMIARID REGION OF BRAZIL

“…Several studies have also found this thiarid snail associated with macrophytes (MANSUR et al, 2012;MEDEIROS;HENRY-SILVA, 2017;OLIVEIRA;OLIVEIRA, 2019). However, the individuals studied here were found on the margins of the reservoir (water and air interface and below the water surface) with no aquatic plants, exposed to direct sunlight in an environment with clearly higher temperatures.…”

New record of the invasive snail Melanoides tuberculata (Gastropoda, Thiaridae) - Ceará State, Brazil

“…The species is adapted to high salinity variation (Santos and Eskinazi-Sant'Anna, 2010;Silva and Barros, 2015), and high temperatures (Gerald and Spezzano Junior, 2005;Elkarmi and Ismail, 2007). M. tuberculata is generally associated with habitats with high vegetation (Medeiros and Henry-Silva, 2017) and anthropogenic alterations, which allow shaded areas for their protection (Rocha-Miranda and Martins-Silva, 2006). Its diet consists preferably of fine debris and periphytic biofilms (Raw et al, 2016).…”