Food-anticipatory activity of groups of golden shiners during both day and night

Abstract

For 12 days, captive groups each containing four golden shiners (Notemigonus crysoleucas) were fed by au- tomatic feeders at two diametrically opposed daily times. These two times could be midday and midnight, late day and late night, or early day and early night. As measured by interruptions of an infrared beam underneath the feeder, golden shiners almost always expressed food-anticipatory activity. Beam interruptions started to increase a few hours before mealtime, reaching a peak within 1.5 h of food delivery. In at least half of the groups tested, food-anticipatory activity developed for both daily times simultaneously. This double anticipation was maintained for at least 5 days after food was withheld. These results show that golden shiner groups (though not necessarily individuals) can express two peaks of food anticipation at widely separated daily times, even if one occurs during the day and the other at night, providing further evidence for the great variability that fishes can display in their activity patterns.