Our sensible mothers told us to leave bees alone so they don\'t get angry with us, but scientists have found that the humble honey-gatherer really do feel some kinds of emotion. A study suggests that, if upset, the bee can display negative emotion just like humans, dogs, rats and birds. In an experiment, scientists disturbed a group of bees at home by shaking their hive violently to simulate an attack by a predator. Later, the way the way the bees responded to odours indicated they had become more supicious and pessimistic in outlook. The scientists, whose findings are reported in the journal Current Biology, had first trained bees to link one odour to a sugary sweet reward and another to bitter quinine. The bees learned the difference between the two and became more likely to extend their mouthparts to the \"sugar\" odour. One group of bees was shaken up while another was left undisturbed. The bees were then presented with the odours again, as well as similar new odours. The shaken bees were now less likely than undisturbed bees to extend their mouthparts to the odour predicting the bitter taste of quinine. They behaved as if they had an increased expectation of a bitter taste. Other odours that were new to them produced the same reaction. Researcher Dr Geraldine Wright, from the University of Newcastle, said: \"We have shown that the emotional responses of bees to an aversive event are more similar to those of humans than previously thought. \"Bees stressed by a simulated predator attack exhibit pessimism mirroring that seen in depressed and anxious people.\" \"What we have shown is that when a honeybee is subjected to a manipulation of its state that in humans would induce a feeling of anxiety, the bees show a similar suite of changes in physiology, cognition, and behaviour to those we would measure in an anxious human,\" said Dr Wright. \"In terms of what we are able to measure, a shaken honeybee is no less \'anxious\' than a lonely dog or a rat in a barren cage.\" The scientists believe feeling blue is not unique to bees, and other invertebrates probably behave the same way.