Studies of bees' brains could shed light on how people learn

By Jim Barlow

Can honey bees help scientists understand how adult humans learn? 
Researchers at the UI are convinced they can.

In the July 15 issue of the journal Nature, they describe structural 
changes that occur in the brains of bees when the insects leave their 
domestic chores to tackle their most challenging and complex task - 
foraging for pollen and nectar.

As part of a doctoral thesis, neuroscience graduate student Ginger S. 
Withers focused on the "mushroom bodies," a region of the insect brain so
named because it appears mushroom-shaped when viewed in cross-section. The
region is closely associated with learning and memory.

Withers used quantitative neuroanatomical methods to study sections of bee
brains to show that the mushroom bodies are reorganized when a bee becomes
a forager. Although a honey bee typically switches from hive-keeping 
tasks, such as rearing younger sisters and caring for the queen, to 
foraging at about three weeks of age, the brain changes are not simply due
to aging. In a key experiment, young honey bees were forced to become 
foragers by removing older bees from the colony. The mushroom bodies of 
the precocious foragers, who were only about 1 week old, mirrored those of
normal-aged foragers.

The findings suggest that nerve cells in the mushroom bodies receive more
informational inputs per cell as the bee learns to forage. In order to be
a successful forager, a bee must learn how to navigate to and from its 
hive and how to collect food efficiently from many different types of 
flowers.
 
The implications for neuroscience go far beyond the beehive, said the 
article's co-authors, UI insect biologists Susan E. Fahrbach and Gene E. 
Robinson. There could be application to human studies, they said, because
the structure of bee brains is similar to - but much simpler than - human
brains.

Fahrbach, whose research has focused on the impact of hormones on the 
nervous system, was drawn to the honey bee by its sophisticated behavior,
small brain and power of concentration. "Honey bees offer an exceptionally
powerful model for the study of changes in the brain related to naturally
occurring changes in behavior, because, once a bee becomes a forager, it 
does nothing else," she said. "Because the behavioral shifts are so 
complete, the changes in brain structure that accompany the behavioral 
transitions must be related to the performance of the new observed 
behavior."
 
Robinson, who is director of the UI's Bee Research Facility and who has 
previously studied other physiological and genetic aspects of bee 
behavior, agrees: "This discovery opens a new area of research on the 
relationship between brain and behavioral plasticity. One fundamental 
question this research raises is 'which comes first?' Do changes in 
behavior lead to changes in brain structure? Or do the changes in brain 
structure occur first, in preparation for the changes in behavior?"

As researchers pursue the changes in brain cells that form the 
underpinnings of learning, the UI scientists say the combination of 
neuroscience and entomology may yield sweet rewards. 


UIUC -- Inside Illinois -- 1993/09-02-93