Predation on eggs of the apple snail Pomacea dolioides (Reeve, 1856) in rural and urban areas of the Amazon

Abstract

This study investigated the predation of eggs of the apple snail Pomacea dolioides in Itacoatiara, Amazonas, Brazil. Predation was compared between rural and urban areas, period of day, shaded and unshaded clutches. In addition, we evaluated clutch height and the behaviour of predators. Between April 2017 and July 2018, 962 egg clutches were observed at different times of the day: 492 in rural areas with predation of 68 egg clutches and 470 in urban areas with predation of only 9 egg clutches. Significant differences were recorded for predation rate and differences were recorded for egg clutch height in the areas. In the rural areas, the most frequent predators during the day were ants Solenopsis invicta, Crematogaster cf. carinata and the most abundant were S. invicta, Wasmannia aff. iheringi and C. cf. carinata. During the night, S. invicta was the most frequent and abundant predator. In urban areas, the frequency of predation and abundance of S. invicta were higher during the day and night than those of other predators. Populations of P. dolioides in rural areas are more affected by egg predation, mostly by S. invicta and C. cf. carinata, and predatory behaviour depended on the species of the predator.