Master’s degree project in Biology

The degree project may comprise 30-60 credits and can be carried out in a research group at the Department of Biology or at an external institution e.g. at another faculty or elsewhere.

Prerequisites for the Master’s degree project in Biology

• 45 cr Advanced courses in Biology    
• A Bachelor’s degree including 90 cr in Cell Biology, Genetics, Microbiology, Ecology, Botany and Zoology

Interested in carrying out a degree project?

If you don't find any of the projects below to your liking, please contact any of the research groups at the Department of Biology.

Proposals for master degree projects in

Sensory Biology

Magnetic alignment in animals

Many invertebrates, but also vertebrates like deer, cows and foxes, have been shown to align their body axis along the Earth’s magnetic field when resting or feeding. Why they do this is currently not known, but it has been speculated that certain physiological processes work better when the animals are aligned along the magnetic field. It may also be an evolutionary advantage to always be oriented in space by having the body axis aligned along the magnetic field; an animals that suddenly has to flee from a predator will more likely find back, if it was oriented and knew in what direction it flew than an animal which was not oriented.

The aim of this project is to examine whether how common this phenomenon is, i.e., whether animals of diverse species here in Sweden also show this behaviour.

If you are interested in a Bachelor’s or Master’s project, don’t hesitate to contact me for more information.

Contact: Rachel Muheim

Use of magnetic cues to find a food reward in birds

Birds can use different cues to locate a hidden food source. They have been shown to use landmarks, but also directional information and positional cues from the sun and the Earth’s magnetic field. Pigeons, for example, have been shown to be able to locate a hidden food reward “marked” with an artificial magnetic field produced by small kitchen magnets. The aim of this project is to investigate whether also other birds, like e.g., zebra finches or tits, can use magnetic cues to find a food reward, by training them to choose between two food trays, one marked with a magnet and the other not.

If you are interested in Bachelor’s or Master’s project, don’t hesitate to contact me for more information. The fieldwork is carried out at Stensoffa Ecological field station all year round.

Contact: Rachel Muheim

The sky compass of dung beetles

To determine their travel direction, many animals use a skylight compass. This compass can get information from the sun's position in the sky, the pattern of polarised light in the sky, and the gradient of intensity and colour of skylight. We still know little about how this information is combined to form a compass that is accurate and robust at different times and weather conditions.

After locating a fresh patch of dung in the deserts and savannahs of South Africa, a dung beetle quickly forms a dung-ball and rolls it away in a straight line to escape the competition at the dung pile. Despite the fact that they are rolling a dung ball many times their own weight while walking backwards on rough terrain, dung beetles show a remarkable ability to maintain a straight path. They achieve this by using a sky compass. In the lab, we can manipulate the visual cues that are available to beetles and then measure how this affects their rolling behaviour. Possible questions for future projects include the hierarchy of cues (is the sun more reliable than the polarisation pattern?), the spectral sensitivity of the polarisation pathway (is polarised light analysed in the UV or the green photoreceptors?), and the use of intensity and spectral gradient. The project involves behavioural studies in the lab, and possibly even field studies in South Africa. We also encourage you to come up with your own questions!

If you are interested in doing your Bachelor's or Master's thesis on dung beetles, please contact Jochen Smolka for further information.

Ultraviolet reflections from urine scent marks

Falcons and other birds of prey have been shown to detect areas with high vole density by sensing ultraviolet reflections from the urine scent marks that these rodents leave on their tracks. Owls, in contrast have been shown not to use this information.

Although the behavioural and field studies on this topic have been performed already more than 10 years ago, the sensory basis is still not clearly understood. It was, for instance, unknown whether the lens of owls and raptors differ in the amount of ultraviolet light that they transmit – or absorb.

We have recently started to measure UV-transmittance of the lens (in general, all ocular media including the cornea and vitreous) and we are now able to model rather precisely what the raptors and owls can see.

The data we still need to measure are the reflective properties of rodent faces and urine. Establishing such a data set will be part of this project. The second part will consist of modeling what the birds see, and which exact cue is likely to be used for the detection of voles.

We will also – and with some luck this will also part of this project – continue to measure ocular transmittance in more species and individuals of owls and raptors. This part, however, depends to our access to animals.

For more information, please contact Almut Kelber

Light-dependent magnetoreception in birds

Birds have a light-dependent magnetic compass which they use to orient during migration and very likely also in their daily life. This compass is thought to be located in specialized, magnetosensitive photoreceptors in the eyes, enabling the birds to perceive the Earth’s magnetic field as a three-dimensional pattern of light irradiance or colour variation superimposed on their visual field. Cryptochromes have been proposed as likely candidates for such magnetoreceptor molecules, but the actual receptors have not yet been conclusively identified and located in birds, thus the question how birds can perceive magnetic compass information remains one of the big mysteries in sensory biology!

By testing the orientation of migratory birds in funnel experiments or in a spatial orientation task in a maze under various light and magnetic field conditions, we can study in more detail how the magnetic compass in birds is functioning.

If you are interested in light-dependent magnetoreception in birds for your Bachelors or Master’s project, don’t hesitate to contact me for more information. The fieldwork is carried out at Stensoffa Ecological field station during spring and autumn migration (orientation experiments) or year round (maze experiments).

Please contact Rachel Muheim if you are interested in this proposal.

Polarized light sensitivity in birds

The ability to perceive the third dimension of light, i.e., its polarization or alignment of the electric vector, has been well described in a wide variety of animals. Despite of convincing evidence that birds use cues from the skylight polarization pattern for orientation and compass calibration, we know almost nothing about how they can perceive this information. While the polarized light receptors in many invertebrates and some fish species are relatively well studied, birds do not have any obvious receptors in their eyes, thus the question of how they are able to detect polarized light information still remains to be solved.

We investigate the behavioural and functional properties of polarized light sensitivity in birds using a recently developed spatial orientation assay. We train birds to use the axial alignment of overhead PL cues to locate a hidden food source. By manipulating the properties of the polarized light used during the experiments, we can study for example the sensitivity of polarized light vision in birds, allowing us to make predictions under what natural conditions birds are able to use information from the skylight polarization pattern.

If you are interested in studying the behavioural and physiological mechanisms of polarized light sensitivity in birds in your Bachelors or Master’s project, don’t hesitate to contact me for more information. The fieldwork is carried out at Stensoffa Ecological field station year round.

Please contact Rachel Muheim if you are interested in this proposal.

What did the first eyes see?
Would you like to study a “living fossil”?

Eyes evolved around 540 Mya and are thought to have triggered the Cambrian explosion, the sudden radiation of species in the Cambrian. Some of the earliest animals that had eyes were arthropods. Unfortunately, we know almost nothing about the visual abilities of ancestral arthropods. A particularly interesting group to study in this respect are onychophorans, close relatives of the Euarthropoda (insects, crustaceans, spiders etc.). Onychophorans have not changed much since the Early Cambrian and are therefore regarded as “living fossils”. Because of their conservative anatomy, onychophorans can help to reconstruct the ancestral arthropod.

All onychophorans are ambush predators that inhabit forests of the southern hemisphere and at the equator and hunt small invertebrates at night. They have two simple, camera-type eyes - one on each side of the head just behind the antenna. Although the eyes seem to have reasonable image-forming capacities, prey is not primarily detected visually. The antennae are the main means by which prey is investigated. However, both known cave-dwelling species have lost their eyes. This implies that vision serves a role important enough for the remaining onychophorans to maintain their eyes. While subterranean species are pale, many other onychophorans are brightly coloured (see figure A and B). Are the animals able to differentiate between these colours? Does the spatial resolution of their eyes actually allow them to see conspecifics? Which advantages could colour vision have without useful spatial resolution? These and many other questions await an answer...

Figure: Position and external appearance of eyes in onychophorans
A) A colourful onychophoran species: The arrow points to the eye situated near the antennal base.
C) Scanning electron micrograph of the eye in an adult specimen.
Pictures: Courtesy of Dr. Georg Mayer

If you want to shed light on this poorly studied animal group, please contact us. We are happy to provide you with our plans for a Masters thesis. We also encourage you to come up with your own ideas. Your work will be part of a major project that involves investigations of the optical properties of the eyes, behavioural tests, electrophysiology and molecular studies. There is for sure something that will suit you.

Involved researchers:
Miriam Henze (Lund University), Almut Kelber (Lund University), Dan-Eric Nilsson (Lund University) and Georg Mayer (University of Leipzig, Germany)

Please contact Miriam Henze if you are interested in this proposal.

Receptors out of place!
Study the mysterious “ventral stripe” in the cricket compound eye!

Crickets have regionalized compound eyes, i.e. different parts of their eyes are used for different purposes. For instance, blue receptors at the upper margin of the eye, the so-called dorsal rim area, are specialized to detect the oscillation angle of polarized light. The polarization pattern in the sky (which is invisible to humans) can therefore serve crickets as a compass for navigation.

We have recently shown that blue receptors are not only found in the dorsal rim area of the cricket compound eye, but also in a well defined “ventral stripe”. The function of this “ventral stripe” is unknown. There are many questions that need to be answered: Are the ventral blue receptors also polarization sensitive? If so, what are they used for? Some flying insects find water surfaces by ventral polarization detectors. However, crickets hardly ever fly. Neither do they have to find water surfaces for reproduction or feeding.

If you are interested in these questions, do not hesitate to contact us! We are happy to provide you with further information on the project. A Masters thesis could include electrophysiological recordings, electron microscopy or behavioural tests. Please feel free to tell us your preferences. You are also welcome to make your own suggestions, of course.

Figure: Blue receptors in the compound eye of the cricket
Blue receptors are not only found in the polarization-sensitive dorsal rim area but also in a confined ventral stripe of unknown function.
Picture: Courtesy of Martin Kohler and Dr. Miriam Henze

Involved researchers:
Miriam Henze, Almut Kelber and Eric Warrant

Please contact Miriam Henze if you are interested in this proposal.

How does visual input modulate the swimming system of box jellyfish?

Box jellyfish represent the most basal group of animals possessing eyes. Eight eyes are of the camera type, which means that they are quite similar to ours! With their 24 eyes they can display visually guided behaviours which are quite unexpected for a jellyfish.

Visually guided swimming is only possible through interactions with the surrounding water. The aim of this project is to investigate how the swimming system of box jellyfish is modulated by the visual input. This will be done by stimulating one, or several, eyes and measuring electrical signals running through the ring nerve. The ring nerve connects the visual system of the animal with the swimming musculature.

Please contact Ronald Petie if you are interested in this proposal.

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