Short-term effect of different weather conditions upon the behaviour of forager and nurse honey bees (Apis mellifera carnica Pollmann)

Nurses and foragers were observed around noon and around midnight during good and bad weather conditions. Foragers were very busy on sunny days with almost no periods of inactivity. More than 60% of the observation period around noon they spent outside the live. When foragers were prevented from flight by the lack of light or by bad weather, they showed long periods that were defined as unproductive and trophallactic contacts were reduced. Nurses aged 7-9 days showed a less pronounced behavioural difference between day and night but were highly sensitive to weather alterations. They spent less than half of the time nursing the brood during bad weather conditions compared to good weather conditions, although there was no lack of pollen and honey in the colony. The same tendency was observed in other nurse related activities. They were less often fed by other bees during days with bad weather conditions than during days with good weather conditions. These dramatic changes in behaviour could be observed even on the first day of rain. We presume that the decline of activity is at least partly caused by the diminishing flow of food within a colony.