Determining the time delay of honey bee (Apis mellifera) foraging responseto hourly pollen release in a typical pollen flower (Cistus salvifolius)

We estimated pollen release from hourly stamen samples of a typical pollen flower, Cistus salvifolius, and determined the daily pollen presentation sc hedule. Half-hourly honey bee (Apis mellifera) pollen foraging on C. salvif olius varied significantly within and between days even though data were on ly collected on clear sunny days. We found that flower observations varied between flower patches of a very restricted area. We fitted a simple linear model to half-hourly pollen foraging and used the model to predict observe d pollen release. For each day, we calculated the optimal time delay betwee n pollen foraging and pollen release. For 9 out of 10 days the time delay w as between 28 min and 60 min. The average pollen foraging was about 44 min time delayed compared to average hourly pollen release. Incorporating the t ime delay in the pollen foraging model to predict pollen release for each o f the 10 days, we found a non-significant difference between observed and p redicted hourly pollen release for all days. We therefore suggest that poll en foraging of honey bees is determined by the pollen availability and that monitoring of hourly pollen release in entomophilous flowers may be done t hrough simple observations of pollinator for-aging.