Sunday, 20 May 2012

Similarity between humans and bees?




Can bees have personality?
Scientists focused their research on experiments using honeybees, Apis mellifera. The aim of the study was to test whether it’s correct that some bees can be more adventurous than others and if there is any biochemical indication in their brains that suggest that. Also, they aimed to find out if it’s true that some bees go to try new food sources whereas the others follow these “scout” bees.

How was the experiment?
The experiment consisted in placing a hive in an enclosure with a unique food source. Then, after 2 to 3 days of training the bees with the feeder, a new feeder with different odor and visual was added to the enclosure. The bees had two sources of aliment, atypical and habitual. This procedure was repeated many times, changing the odors, visual and location of the new feeder. As a result, the scientists observed that some bees kept going to different aliment sources, but some switched to more than two distinct novel feeders. Those that changed were collected as scouts and their brain gene expression was compared with the non-scouts genes. The scientists found more than a 1000 different active genes in the brain tissues of scouts and non-scouts. 
In continuity to the experiment, several non-scouts bees were collected. The treatment of an oral neurochemical was given to the bees during a period of 25 to 30 hours and 14 hours after the stopping of the treatment their behavior was observed. The results revealed that after glutamate, non-scout bees showed interest in scouting. On the other hand, octopamine, which is a neurotransmitter and is responsible for causing excitability caused weakness in the bees, but still motivated them for scouting


What’s the similarity between human and bees genes?
Among the expressed genes in the scout bees brain tissues, cathecholamine and glutamate were found, which are also present in human genes. Cathecholamines have the same molecule pathway as dopamine and adrenaline that is known as “fight-or-flight” hormone, released by the adrenal medulla under stress situation. There is also evidence that people with novelty-seeking personalities show higher levels of dopamine than more introvert people. However, the results showed that scout bees have an opposite reaction, instead of been more likely to new experiences they were averse to that. 


Can we really affirm that bees have personalities?
This whole experiment raises questions between the relationship of honeybees and humans in novelty-seeking behavior. Even thought the molecular mechanisms that produce the variation in behavior are similar, there is no concrete evidence that they developed these characteristics independently, or from a common ancestor. 



References
  • Z.S. Liang et al. Molecular determinants of scouting behavior in honey bees. Science. Vol. 335, March 9, 2012, p. 1225. doi:10.1126/science.1213962.
  • Rachel Ehrenberg, 2012, 'Bee genes may drive them to adventure', Science news, viewed 19 March 2012, <http://www.sciencenews.org/view/generic/id/339036/title/Bee_genes_may_drive_them_to_adventure>.
  • Neil A. Campbell, Jane B. Reece, Noel Meyers, Robert B. Jackson, Michael B. Cain, Lisa A. Urry, Peter V. Minorsky, Steven A. Wasserman, Biology 8th edn, Pearson, Australia.

Patrizia Bandini
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