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Standardization of the Compass Neuropils of the Australian Bogong Moth, Agrotis infusa

de Vries, Liv (2016) MOBK01 20152
Degree Projects in Molecular Biology
Abstract
Every summer the Australian Bogong moth migrates from southern Queensland to the Australian Alps in southern New South Wales. Other migrants such as the monarch butterfly use a time-compensated sun compass. However, the Bogong is nocturnal and only has access to skylight cues such as the moon, polarized light or the Milky Way. Since these are considerably unreliable only being visible short periods of time, another navigational mechanism could be a magnetic compass. In the Monarch the brain regions (neuropils) involved in navigation are the central complex, the lateral accessory lobes and the anterior optic tubercles; which together are called the ‘compass neuropils’. As the brain anatomy is the structural basis for all information... (More)
Every summer the Australian Bogong moth migrates from southern Queensland to the Australian Alps in southern New South Wales. Other migrants such as the monarch butterfly use a time-compensated sun compass. However, the Bogong is nocturnal and only has access to skylight cues such as the moon, polarized light or the Milky Way. Since these are considerably unreliable only being visible short periods of time, another navigational mechanism could be a magnetic compass. In the Monarch the brain regions (neuropils) involved in navigation are the central complex, the lateral accessory lobes and the anterior optic tubercles; which together are called the ‘compass neuropils’. As the brain anatomy is the structural basis for all information processing underlying orientation and navigation, it can be used as an access point to understand this extraordinary migratory behaviour. We therefore performed 3D-reconstruction of the compass neuropils of the Bogong moth brain. By generating a standardized version of the compass neuropils I have created a common frame of reference for registration of neuron morphologies and networks, as well as providing reference volumes that were compared to those of the monarch. The Bogong moth brain was found to contain all the compass neuropils, however there was a significant difference between the two species neuropil-volumes. Interestingly, all components of the central complex were larger in the Bogong, while the upper unit of the anterior optic tubercle was substantially larger in the Monarch. (Less)
Popular Abstract
The great Australian journey

Imagine traveling on foot, only by night, from Lund to Rom. This is the distance the Australian Bogong moth, Agrotis infusa, travels to come to its summer hibernation habitat, caves in the alps of southern New South Wales. To put it in relative terms it would be for us the same distance as from Lund to Tokyo. Frankly, we would get lost without the use of a GPS, but the Bogong moth manages this feat every summer. Even more impressive is the fact that they manage to find their way with no previous experience. The experienced migrants die shortly after their return to their winter habitat in southern Queensland, once they have mated and laid eggs.

So the question is how do they manage to find their way?... (More)
The great Australian journey

Imagine traveling on foot, only by night, from Lund to Rom. This is the distance the Australian Bogong moth, Agrotis infusa, travels to come to its summer hibernation habitat, caves in the alps of southern New South Wales. To put it in relative terms it would be for us the same distance as from Lund to Tokyo. Frankly, we would get lost without the use of a GPS, but the Bogong moth manages this feat every summer. Even more impressive is the fact that they manage to find their way with no previous experience. The experienced migrants die shortly after their return to their winter habitat in southern Queensland, once they have mated and laid eggs.

So the question is how do they manage to find their way? Similar migrants such as the monarch butterfly use the sun to navigate, their brains have been found to contain a socalled sun compass. But what does the Bogong use? It travels by night so there are only the moon and the stars, both of which are unreliable in visibility or very dim. A more reliable cue would be the Earths magnetic field. However, the first question which needs to be answered is “Does the Bogong brain have a compass?”

By 3D reconstruction of the midline spanning brain areas of the Bogong I found that the Bogong brain does contain the same areas that are functioning as an internal compass in the Monarch butterfly. There was however a noteworthy difference in relative size between the two. The Bogong moths’ compass regions were generally larger. What this difference in size entails could be a subject for further studies.

The average-shape 3D model of the compass areas generated here will facilitate a greater understanding of how the Bogong manages to navigate in the dark, without any previous experience. For example, by mapping the neuron network which sends information to and from the compass areas, as well as the neurons within, we will establish the anatomical framework needed to target specific neurons by functional studies. Those will eventually resolve if the Bogong moth truly has a magnetic compass. By understanding how these great travellers navigate we can integrate that knowledge into our own future navigational systems and then maybe we will find our way home.

Supervisor: Stanley Heinze
Degree Project, 15 credits, 2015
Department of Biology, Lund University (Less)
Please use this url to cite or link to this publication:
author
de Vries, Liv
supervisor
organization
course
MOBK01 20152
year
type
M2 - Bachelor Degree
subject
language
English
id
8839807
date added to LUP
2016-03-09 16:18:08
date last changed
2016-03-09 16:18:08
@misc{8839807,
  abstract     = {Every summer the Australian Bogong moth migrates from southern Queensland to the Australian Alps in southern New South Wales. Other migrants such as the monarch butterfly use a time-compensated sun compass. However, the Bogong is nocturnal and only has access to skylight cues such as the moon, polarized light or the Milky Way. Since these are considerably unreliable only being visible short periods of time, another navigational mechanism could be a magnetic compass. In the Monarch the brain regions (neuropils) involved in navigation are the central complex, the lateral accessory lobes and the anterior optic tubercles; which together are called the ‘compass neuropils’. As the brain anatomy is the structural basis for all information processing underlying orientation and navigation, it can be used as an access point to understand this extraordinary migratory behaviour. We therefore performed 3D-reconstruction of the compass neuropils of the Bogong moth brain. By generating a standardized version of the compass neuropils I have created a common frame of reference for registration of neuron morphologies and networks, as well as providing reference volumes that were compared to those of the monarch. The Bogong moth brain was found to contain all the compass neuropils, however there was a significant difference between the two species neuropil-volumes. Interestingly, all components of the central complex were larger in the Bogong, while the upper unit of the anterior optic tubercle was substantially larger in the Monarch.},
  author       = {de Vries, Liv},
  language     = {eng},
  note         = {Student Paper},
  title        = {Standardization of the Compass Neuropils of the Australian Bogong Moth, Agrotis infusa},
  year         = {2016},
}