As promised last week in the post Are Bees Wild or Domestic I am going to discuss an experiment that suggests a link between behavioral genetics and development. This experiment was done with foxes bred for tamability. In an attempt to discover how wild animals were transformed into the many domesticated forms known today.
For years it had been debated. How did animals become domesticated? For instance did humans chose to domesticate wolves or did wolves chose to be domesticated by us culminating in the dog? Another stumbling block in the idea of domestication was that some believed that the road to domestication for say dogs, was based on size, and reproductive traits, others believed differently. Dmitry Belyaev was a Russian scientist who believe that domestication came from selective breeding based primarily on behavior; specifically, the behavior of being tame. He theorized that selecting animals for behavior may lead to other far reaching unintended changes in the animal’s development.
Sometime in 1959 Belyaev began his experiments with 30 male foxes and 100 vixens. He began to select foxes that showed the least fear of humans (and didn’t bite them). After about 10 generations definite changes had taken place. The population of foxes no longer showed fear of humans, began waging their tails and licking caretakers as a sign of affection. Physiological changes were becoming evident as well with spotted coats, floppy ears, and curled tails. Strangely all similar characteristics to those seen in dogs as well as other domesticated animals.
Neurochemical changes appear to have taken place as well. There was an observed decrease in the production of adrenalin in this population of foxes. Adrenalin is a neurochemical that plays a key role in fight or flight response in animals. There was also a decrease in the basal levels of corticosteroid hormones. These hormones play a role in an animals response to stress.
Along with the physical and neurochemical changes there were also changes in the fox’s developmental and social behaviors. Domesticated fox pups began responding to auditory stimuli two days earlier, and opened their eyes earlier when compared to wild foxes. Domesticated pups show a fear response at 9 weeks as compared to 6 weeks in wild foxes. Dogs typically show a fear response at 8-12 weeks depending on the breed. Belyaev thus found that domestication could cause changes in post natal development of physiological and hormonal mechanisms that ultimately led to changes in social behavior.
If Belyaev’s model was properly executed it tends to indicate that selecting animals for behavioral traits alone can fundamentally change that organism. The next question is would bees, being insects, have similar outcomes if subjected to similar forms of selection?
Undoubtedly the contrarian could attest that bees are not foxes, they aren’t even mammals and that is undeniable. Even if we can’t expect the same changes in bees through selection based on behavior, it seems foolhardy to assert that there will be no consequences from such selection. I have read about changes in honeybees in the last 100-150 years. For one, there are reports and articles that propolis production has been decreased. Also the physical size of the honeybee has been altered. What other things have changed?
What do you think?
- Is it possible that by selecting against protective behavior we could cause unforeseen problems?
- What if being more tolerant to human intrusions into the hive also would translate into a decrease in aggression towards other hive intruders such as wax moths, small hive beetles, and varroa mites?
- Given the hardships faced by bees currently would it be wise to allow the bees to do their own selection based upon on ability to withstand pests and/or overwinter as opposed to whether we get stung or not?
Pose some answers in the comments and have a great weekend.
If you would like more information about the fox experiment visit:
Many of the pictures in this post are NOT my own. I am not attempting to seek financial gain from them or claim they are my own.