A recent study by Gross et al (2009) looked at the counting ability of the honey bee, Apis mellifera, by using a series of numerical patterns in branched mazes. The researchers found that bees trained with a sugar reward could tell the difference between patterns containing two or three elements by counting, rather than remembering the patterns. For a control the researchers altered the colour and layout of the elements in the patterns.

Without any further training the researchers found that the bees could differentiate between patterns containing three or four elements but could not differentiate between four and five, or four and six.

The authors also note that “this is the first report of number-based visual generalisation by an invertebrate”.

I wonder if octopuses can count…

Reference:

Gross H.J., Pahl M., Si A., Zhu H., Tautz J. and Zhang S. (2009) Number-Based Visual Generalisation in the Honeybee. PLoS ONE 4(1): e4263. doi:10.1371/journal.pone.0004263