Alternativas de uso de Ampullariidae em áreas invadidas como manejo conservativo e predação de ovos do gastrópode Pomacea dolioides (Reeve, 1856) em áreas nativas

Abstract

Apple snails are gastropods considered pests in many parts of the world where they were introduced for aquaculture or trading purposes. In these areas, they alter the environment, damage rice cultivation and cause economic losses. Predation is an interspecific ecological relationship that affects species distribution and abudence. In this study, we review the use and applications of these gastropods considered as pests that may be an alternative for conservative management and investigate the predation of eggs of the Pomacea dolioides gastropod in Itacoatiara, AM, comparing predation between rural and urban areas, shaded and unshaded masses, mass height, preference of predators for newly placed or mature eggs, and predator behavior. Apple snails are created as a food resource for humans or animal feed for crabs, shrimps, chickens, ducks, frogs, pigs and many species of fish and weed control on rice farms. In addition, these gastropods can be indicators of pollution by copper, cadmium, tributyltin and many other contaminants. They are also useful for human health, being used in the control of planorbidids, skin diseases and other treatments in traditional medicine. Substances and materials of snails such as calcium oxide, biodiesel catalyst, chitin and chitosan are extracted. In addition, they generate income being sold as ornamental animals for aquariums, their shells are also marketed or used in crafts. Between April 2017 and July 2018, there were 962 egg masses at different times of the day, 492 in rural areas with 68 predation, and in urban areas of 470 only 9 were predated. There was a difference for the mean height of the egg masses between the areas (t=15.9223; GL=960; P=0.0016). The most frequent substrate of predation in rural areas was the Montrichardia linifera plant and in urban areas the wood substrate. Predation rate in general was significantly different between the two areas (χ2=39.637; GL=1; P> 0.0001). The most frequent predators in rural areas during the daytime period were ants of the genus Solenopsis invicta (N=18; 45%) and Crematogaster cf. carinata (N=6; 15%) and the most abundant S. invicta (N=271; 49.82%), Wasmannia aff. inheringi (N=162; 29.78%) and C. cf. carinata (N=62; 11.40%). During the night time S. invicta was the most frequent (N=18; 64.29%) and abundant (N=251; 76.52%). In urban areas during the day, the most frequent predator (N=5; 83.33%) and abundance (N=25; 86.21%) was S. invicta. At night time, this same genus was also the most frequent (N=3; 100%) and abundant (N=10; 100%). There was no difference in the preference of predators for newly placed or mature eggs between the periods of the day in urban areas (χ2=0.772; GL=1; P>0.7823). Apple snails can be used in different ways to benefit humans, even in introduced areas, can be alternative to conservative management or in reducing the use of chemicals and source of income. Populations of P. dolioides in rural areas are more affected. The main predators were S.invicta and C. cf. carinata and predatory behavior depends on the species of predator. For the first time the order Pseudoscorpionida and ants of the genus Nylanderia sp., Strumigenys sp., Cyphoomyrmex cf. peltatus, Pheidole aff. Mamore and Cephalotes cf. atratus were registered as predators of Pomacea eggs.