Sex differences in retention after a visual or a spatial discrimination learning task in brood parasitic shiny cowbirds

ASTIE, A.A.; SCARDAMAGLIA, R.; MUZIO, R.N.; REBOREDA, J.C.

BEHAVIOURAL PROCESSES

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 119 p. 99 - 104

0376-6357

tFemales of avian brood parasites, like the shiny cowbird (Molothrus bonariensis), locate host nests and onsubsequent days return to parasitize them. This ecological pressure for remembering the precise locationof multiple host nests may have selected for superior spatial memory abilities. We tested the hypothesisthat shiny cowbirds show sex differences in spatial memory abilities associated with sex differences inhost nest searching behavior and relative hippocampus volume. We evaluated sex differences duringacquisition, reversal and retention after extinction in a visual and a spatial discrimination learning task.Contrary to our prediction, females did not outperform males in the spatial task in either the acquisitionor the reversal phases. Similarly, there were no sex differences in either phase in the visual task. Duringextinction, in both tasks the retention of females was significantly higher than expected by chance up to 50days after the last rewarded session (∼85?90% of the trials with correct responses), but the performanceof males at that time did not differ than that expected by chance. This last result shows a long-termmemory capacity of female shiny cowbirds, which were able to remember information learned usingeither spatial or visual cues after a long retention interval.