FOOD PREFERENCE AND CONSUMPTION OF AQUATIC MACROPHYTES SUBMERGED BY SNAIL Pomacea canaliculata

Abstract

-The objective of this study was to evaluate the consumption potential, food preference and use of snail Pomacea canaliculata as a biocontrol agent of four submerged aquatic macrophytes (Ceratophyllum demersum, Egeria densa, Egeria najas and Hydrilla verticillata). Two experiments were performed. In the first experiment, the introduction of a snail took place and 10 grams of each macrophyte in plastic containers with 1 liter of water. The assessments of consumption by the snail were performed at each 48 hours, during 12 days. The second experiment was performed in 600 liters microcosms containing five snails in each experimental unit. Fifty grams of each macrophyte were offered the snails at the same time, adding the same amounts after seven, 14, 21 and 30 days. On both trials, the most consumed macrophyte by the P. canaliculata was H. verticillata (7.64 ± 1.0 g 48 h and 50 ± 0.18 g) respectively, significantly differing from the others. However, in the absence of H. verticilata, E. najas and E. densa were consumed. The preference of P. canaliculata for H. verticillata is very interesting, because this plant is exotic and problematic in Brazil, and the snail is one more tool for biological management of submerged aquatic macrophyte H. verticillata. Keywords

Biotic resistance by snails and fish to an exotic invasive aquatic plant

“…Cruz et al, 2015 andGrutters, Gross, &Bakker, 2016), and long-term experiments (months to years) that follow plant growth (e.g. Our approach fits between two extremes that have been widely used to test effects of herbivory on macrophytes: short-term experiments that test the feeding of plant fragments only, without testing the growth responses (choice or no-choice experiments; e.g.…”

“…Our approach fits between two extremes that have been widely used to test effects of herbivory on macrophytes: short-term experiments that test the feeding of plant fragments only, without testing the growth responses (choice or no-choice experiments; e.g. Cruz et al, 2015 andGrutters, Gross, &Bakker, 2016), and long-term experiments (months to years) that follow plant growth (e.g. Laguna et al, 2016).…”

“…For example, H. verticillata is frequently consumed by native characid and anostomid fishes in the genera Moenkhausia (N. Carniato, R. R. Braga and L. G. S. Ribas, personal observation) and Schizodon (Isaac, Fernandes, Ganassin, & Hahn, 2014), respectively, and by ampullariid apple snails (Pomacea spp. ; Baker et al, 2010;Cruz et al, 2015), which are very abundant in floodplain lakes (A. A.…”

“…No other submerged species was considered as a potential alternative for herbivorous species because previous experiments showed preferences for H. verticillata compared to native species (e.g. Baker et al, 2010;Cruz et al, 2015).…”

Effects of shading, fertilization and snail grazing on the productivity of the water fern Azolla filiculoides for tropical freshwater aquaculture

“…The golden apple snail Pomacea canaliculata is a freshwater gastropod, native to South America that has become a serious pest in Asian agriculture and is included in the world's 100 worst invasive alien species (Lowe et al, 2000). These snails, present in aquaculture ponds, are herbivorous and can feed on floating macrophytes such as Azolla (Cruz et al, 2015). Golden apple snails have a strong negative effect on the biomass of all macrophyte species in Asian wetlands (Carlsson and Brönmark, 2006) but, to our knowledge, the potential effects of these snails on the production of Azolla in the field have not been investigated.…”