Anna Maria Schmidt

"Influences of natural selection and genetic drift on the mound structure
of the Magnetic Termite Amitermes meridionalis"

Details   May 1999 Abitur at the Gymnasium Hittfeld, district of Hamburg October 1999 Commenced studies of Biology at the University of Hamburg October 2004- July 2005 Diploma thesis with lab experience at the University of Balearic Islands in Palma de Mallorca: "Karyology und Population Genetics of Chrysolina aurichalcea (Coleoptera: Chrysomelidae)" August 2005 Commenced PhD-Thesis at the University of Regensburg under the supervision of Dr. Judith Korb

Research interests:

My main research interests are in evolutionary biology and behavioural ecology. In my PhD-thesis I want to connect these topics and investigate the evolution of specialized adaptive behaviour.
Higher termites provide a perfect model for these kinds of investigations because not only do they show very interesting social behaviour, but also build impressive above-ground structures, the termite mounds.

The mounds of Amitermes meridionalis are amongst the most remarkable mounds of all termite species, and this is why we selected this species for further exploration. This species is endemic to a small area of the Northern Territory of Australia. The termite mounds represent a famous tourist attraction in national parks such as Litchfield National Park. In contrast to the mound shape of all other termite species A. meridionalis mounds possess an elongated axis that is always orientated in a north-south direction, and are wedge-shaped towards the top. They can reach up to 4 meters in height and occur on alluvial plains, often in clusters of 20-100 mounds.

Termite mounds of Amitermes meridionalis

The termites seem to be able to sense the earth's magnet field and align their mounds accordingly. The shape of termite mounds is specific, highly adaptive and genetically fixed. Mounds of all other termite species are more or less spherical, so this unique shape of A. meridionalis mounds seems to have a special adaptive value however it is not known what. Our collaborator, Peter Jacklyn, conducted some experiments that focused on the striking north-south orientation of the mounds. He discovered that this orientation is the most advantageous regarding the shape of the mounds because it ensures the best possible temperature stability inside the nest. Regarding the biological significance of the unique mound shapes, Judith Korb has developed some hypotheses that I will test with selective manipulations.

Installed dataloggers: internal logger (left), main station (middle), sensor for surface temperature (right)

The second part of my thesis is based on the observation that magnetic mounds differ in their exact orientation between the different flood plains. The observation has been interpreted as a special adaptation to local environmental conditions such as shading or differences in wind speed. Another possible explanation is based on the fact that termite colonies are often geographically quite isolated from each other, thus making factors like genetic drift and isolation by distance highly probable. This fact is strengthened by the poor flying ability of the winged reproductives, the alates. A genetic exchange between such geographically isolated sites becomes quite implausible.
With the aid of genetic markers I aim to answer these and other basic questions regarding the relationship between mounds and colonies, colony structure etc.

In this study the influence of chance and natural selection on the structure of magnetic mounds can be determined and a model system for the role of chance in behavioural ecology could be created.

Hunting spider with termite

Internal mound structure

Swarmed alates in puddle