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Navigational guiding neurons in the sweat bee Megalopta genalis

Gustafsson, Elin (2022) MOBK01 20212
Degree Projects in Molecular Biology
Popular Abstract
Tiny brains make sophisticated navigational decisions

Did you know that your brain is made up of 100 billion neurons?
That´s as many as there are stars in the Milky Way. This makes the human brain, without a doubt, the most complex system on earth.

Above all the brain controls behavior. But how can we even begin to understand these hundreds of trillions of interconnections that lead us to a specific action? Well, we have to turn to simpler systems; like the ones of insects. Despite our tremendous differences in size and abilities, we are both biological beings with some similar basics.

The ordinary fruit fly; Drosophila melanogaster has a tiny brain, made up of merely 100 000 neurons. Yet it expresses a surprisingly... (More)
Tiny brains make sophisticated navigational decisions

Did you know that your brain is made up of 100 billion neurons?
That´s as many as there are stars in the Milky Way. This makes the human brain, without a doubt, the most complex system on earth.

Above all the brain controls behavior. But how can we even begin to understand these hundreds of trillions of interconnections that lead us to a specific action? Well, we have to turn to simpler systems; like the ones of insects. Despite our tremendous differences in size and abilities, we are both biological beings with some similar basics.

The ordinary fruit fly; Drosophila melanogaster has a tiny brain, made up of merely 100 000 neurons. Yet it expresses a surprisingly sophisticated navigational behavior. When you get hungry, you usually just have to open your fridge to find food. For the fly this requires that it can make reliable navigational decisions in relation to its surroundings. If its current and intended headings are not aligned, its brain must initiate a turning decision. Further, the tropical sweat bee Megalopta Genalis can find its way back to its nest in seemingly complete darkness. To do this they for instance rely on dorsal vision ques, like the silhouette of the tree tops in contrast to the night sky, as well as the arrangement of landmarks. All these navigational computations are performed by a region in the brain called the central complex.

Researchers have recently been able to map all neural connections of the central complex in the Drosophila fly. Interestingly, this region has largely the same core structure in all insects as it did 400 million years ago. The enormous difference in insect behavior lies in the secondary functions they express. For instance, a bee show a much more advanced homing behavior than a fly. Bee behavior is well studied – although the neural computation behind it is not. Using the Drosophila neural map as a ground truth; the differences can reveal the specific specializations that differ substantially in each species.

With high resolution images of the Megalopta brain, divided in 50nm thin sections, the neurons in the central complex can be traced and reconstructed in a computer program. Recently a new type of neurons has been discovered in Megalopta that don’t seem to have a direct counterpart in flies. These neurons, called PFx, target neurons called PFL. They are responsible for the motor output e.g. how the insect uses its muscles, for instance in which direction to turn their head, how to move their legs and so on. I have traced, reconstructed and compared the PFx neurons in Megalopta with potentially homologous neurons in Drosophila and have come to the conclusion that; the PFx neurons are most likely crucial to guide bee navigational behavior.


Supervisor: Stanley Heinze
Bachelor thesis, 15 cr, Molecular Biology
Department of Biology, Lund University (Less)
Please use this url to cite or link to this publication:
author
Gustafsson, Elin
supervisor
organization
course
MOBK01 20212
year
type
M2 - Bachelor Degree
subject
language
English
id
9077599
date added to LUP
2022-03-24 15:02:21
date last changed
2022-03-24 15:02:21
@misc{9077599,
  author       = {{Gustafsson, Elin}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Navigational guiding neurons in the sweat bee Megalopta genalis}},
  year         = {{2022}},
}