Honeybees can count up to four

January 28th, 2009 - 2:35 pm ICT by ANI  

Washington, January 28 (ANI): An international team of scientists has found that honeybees can tell the difference between different numbers at a glance.
Dr. Shaowu Zhang, Chief Investigator of The Vision Centre in Australia and Professor Hans Gross and Professor Juergen Tautz of Wurzburg University in Germany, have revealed that they carried out an exquisitely designed experiment that showed that bees could discriminate between patterns containing two and three dots, without having to count the dots.
Revealing their findings online in the journal PLoS ONE, the researchers said that with a bit of schooling, the bees could learn to tell the difference between three and four dots.
The team, however, found that bee maths seemed to run out at four.
According to the researchers, honeybees couldn”t reliably tell the difference between four dots and five or six.
During the study, the bees flew though an entry of a Y-maze marked with a pattern of either two or three dots, which were signposts to the reward.
The experimental bees then had to choose between two patterns by correctly matching the number of dots, to find where the reward was a feat they then managed to repeat reliably once they had learned that two dots at the first entry meant they had to look for two dots at one of the second pair of patterns, where the reward was hidden.
Dr. Zhang said that careful control over the experimental environment showed the bees were not using colour, smell or other clues to find their way to the hidden sugar-water reward.
“My colleague Professor Srinivasan has demonstrated that bees can count up to four landmarks on their way from their hive to a food source. This new research shows they can tell the difference between different numbers even when we change the pattern, shape or the colour of the dots!” the researcher said.
In their study report, the researchers have revealed that presenting blue and yellow dots, stars and lemons, or random patterns did not fool the clever insects, which continued to reliably navigate their way to the reward once they had figured out and memorised what the signs meant, based on number.
They say that the bees initially spent quite a bit of time scanning the dots, and, on later visits, zipped straight past them as they knew what they meant.
“Bees can definitely recognise the difference between two, three and four although four a little less reliably. This is a process known as ‘’subitizing” which means responding rapidly to a small number of items, they say.
Dr. Zhang says: “We think the bees are using two memory systems. First is working memory, which they use to recall the number of dots that point to the reward. The second system is to use memory rules. We found this out by changing the pattern of the dots - but the bees still managed to locate the reward.”
Dr. Zhang believes that honeybees have perhaps developed this ability as they pass clumps of two trees or three trees on their way to the food source, or use similar patterns among flowers or other landmarks as they draw close to it.
“There has been a lot of evidence that vertebrates, such as pigeons, dolphins or monkeys, have some numerical competence but we never expected to find such abilities in insects. Our feeling now is that so far as these very basic skills go there is probably no boundary between insects, animals and us,” the researcher says.
Shaowu and his colleagues next plan to determine whether bees can actually perform elementary arithmetic. (ANI)

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