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Neural circuits underlying navigational memory across insect species

Jaza, Carina (2021) MOBK01 20202
Degree Projects in Molecular Biology
Popular Abstract
Insects can find their way home as good as some of us

Have you ever been out on field during a summer day, seen bees and ants collecting food far away from their home, and thought: “How do they find their way back home?”. Firstly, understanding insects’ navigational strategies and the underlying neurons responsible for the navigation direction and speed is the first step towards our understanding all animals navigational brain function, because insect have a simpler neural system than, for example, mammalians.

To find their way back home, insects use a navigational process called path integration. This process means that they try and keep track of their speed and distance traveled in relation to their point of origin, meaning their... (More)
Insects can find their way home as good as some of us

Have you ever been out on field during a summer day, seen bees and ants collecting food far away from their home, and thought: “How do they find their way back home?”. Firstly, understanding insects’ navigational strategies and the underlying neurons responsible for the navigation direction and speed is the first step towards our understanding all animals navigational brain function, because insect have a simpler neural system than, for example, mammalians.

To find their way back home, insects use a navigational process called path integration. This process means that they try and keep track of their speed and distance traveled in relation to their point of origin, meaning their home or nest. A part of their brain called the central complex is highly involved in this process and in the overall navigation. These regions can be divided into many smaller parts, each with its’ own importance.

Neurons playing an important part in finding the way home
For any creature to find its’ way back home, some type of memory or recollection of where the home is situated is needed. In insects there are some neurons believed to play a role in the memory of path integration. These neurons are PFN (CPU4)-, PEN (CL2)-, and TN neurons. The PFN neurons are believed to be the memory cell and the more of these the insect has, the higher is its’ ability to use path integration to find its’ way back. These PFN cells receive their stimuli by being connected to the TN cells, which are input cells, meaning that they may receive stimuli from outside stimuli.

In this project we looked at these cells in the army ant, Eciton hamatum, which is an almost blind ant that follows pheromone trails, using a 3D-imaging program called CATMAID. This program is commonly used to trace cells in the brain of insects. Therefore, it is used in many other studies where other insects’ neurons are being traced. Because of this, we will compare the findings of the army and to those previously made in the honeybee-, Apis mellifera, the fruit fly-, Drosophila melanogaster, and the bumblebee-, Bombus terrestris.

It was expected that the army ants showed less PFN cells than the bees and that the memory neurons have a different structure than the flies neural circuit because of the vastly different lifestyles. What was found was that it was very difficult to find PFN cells to track as most turned out to be PEN cells. This indicates that it indeed is far fewer of these memory cells in the army ant in comparison to the bees. Furthermore, it seems as the neurons are not in a circular structure such as they are in the fruit fly. These findings suggest that the pheromone following ant does not use path integration to the same extent or in the same way as do the bees. It also suggests that the because of the different lifestyle and needs the neurons in the flies and the ant are not the same, architecturally. These findings were expected and in accordance with our belief of the outcome.

Supervisor: Stanley Heinze
Bachelor dissertation, 15hp, BIOK01
Lunds University
The Biology Institution FW 2020-2021 (Less)
Please use this url to cite or link to this publication:
author
Jaza, Carina
supervisor
organization
course
MOBK01 20202
year
type
M2 - Bachelor Degree
subject
language
English
id
9040429
date added to LUP
2021-02-15 11:00:57
date last changed
2021-02-15 11:00:57
@misc{9040429,
  author       = {Jaza, Carina},
  language     = {eng},
  note         = {Student Paper},
  title        = {Neural circuits underlying navigational memory across insect species},
  year         = {2021},
}