• Apis mellifera;
  • honeybee;
  • circadian rhythms;
  • locomotor behaviour;
  • entrainment

ABSTRACT. The circadian locomotor (walking) rhythms of individual forager honeybees (Apis mellifera ligustica L.) were measured under a variety of conditions. In constant dark the rhythms exhibited endogenous periodicities that were less than 24 h, whereas under constant light the periods tended to be greater than 24 h. Individual honeybees readily entrained to photoperiods, displaying a diurnal pattern of entrainment with most of the activity occurring in late photophase. Evidence is presented which suggests that foraging behaviour and general locomotor behaviour may be governed by two different circadian clock systems.