Memory of the nectar-feeding bat Glossophaga soricina (Phyllostomidae) / Avaliação da memória de morcegos nectarívoros da espécie Glossophaga soricina (Phyllostomidae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

This study aimed at investigating memory functions of bats (Glossophaga soricina). Four experiments were run. In the Experiment I, preference for sucrose solutions which concentration varied between 10 and 50% was tested; it was shown that these animals exbibit a marked preference for 20% sucrose. In the Experiment II, eight drinkers, being two with the same shape of a total of four different shapes, were made available in specific locations of a panel such that only two of these drinkers, with the same shape, offered 20% sucrose; the shapes of the drinkers and places where they were made available in the panel varied daily, along 25 days. Results showed that (1) the bats promptly learned to obtain food from the drinkers in the panel, (2) 80% of the visits to drinkers in the panel were directed towards drinkers offering sucrose, and (3) at the early visits of every testing day the bats preferably visited the places, but not the shapes, where sucrose was made available the day before, indicating that their spatial memory lasted for at least 15 hours; however, (4) the animals abandomned this search as soon as they detected that it was not effective because in each day the drinkers offering sucrose were placed in different locations. Experiment III reproduced the Experiment II; however, either one of two spatial changes were introduced within the same day, while maintaining the shape rewarded, in order to evaluate the animals´ ability to flexibly react to the spatial change. Results showed that shortly after the spatial the animals direct their visits towards previously rewarded places, but that re-direct their visits towards the new locations; interestingly, this search change was slower when compared to that seen for the spatial change relative to the day before, indicating that the shorter was the time interval relative to the last rewarded locations, the harder was for the bats to re-directed their choices. In addition, when two spatial changes were introduced within the same day, the animals´ re-directioning was quicker after the second change relative to the first change. Experiment IV replicated the results of the Experiment II. Together, these results indicate that bats of this species priorize the use of spatial information about food sources, instead of the shape of these souces, being capable of quickly re-orient their seach when changes are detected.

ASSUNTO(S)

glossophaga soricina foraging bat morcegos - comportamento glossophaga soricina memória espacial memory

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