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The Beetle Lab Detective: A Portrait of Professor Dr. Thorsten Assmann

2017-12-21 The animal ecologist Thorsten Assmann, who counts among the leading ground beetle experts worldwide, has, in a task requiring professional skills and sound judgement, just discovered and described new species again.

Professor Assmann examines it closely. “The palpi’s proportions are very typical for the genus Lebistina. The last segment is strikingly elongated” says the beetle expert looking up from the binocular microscope. This first observation marks the beginning of several days of meticulous efforts. If Assmann presumes this to be new species, he will have to undertake a step-by-step examination of the beetle’s characteristics. The biologist is regarded as an expert on the genus Lebistina within the ground beetles’ expert community. “Researchers caught these in Tanzania and Kenya and passed them on to me” Assmann explains. The beetles are considered very poisonous. Assmann expounds:  “Indigenous peoples lace their arrowheads with the haemolymph; these can kill a giraffe”. 

The expert considers the study of this genus to be very relevant precisely because of its toxicity. “Their toxins may also harbour substances that are important for pharmacy” said Assmann. Active substances extracted from cockroaches are already in use against allergies. As predators, ground beetles in particular are also important for pest control in agriculture. Ultimately, however, the discovery of new species means applied nature conservation to the scientist: “We can only protect what we know. Approximately 40,000 ground beetle species are known worldwide. Experts can only guess how many of them there really are. Many of them may never be discovered because they are extinct before having been identified. “In Central Europe, there are about 1000 ground beetle species. About 30 percent of them are at risk” says Assmann. Reasons for this include habitat loss or intensive agriculture. “Collecting some specimens from the natural environment for determination does not cause these animals to become extinct” says Assmann. Insect populations are comparatively much larger than those of mammals.

A toad in his pocket

As a child, he thought otherwise. “I didn't want to kill insects” recalls the scientist. Even as a young boy, he was interested in everything that crawls and slithers, and had a toad in his pocket or a butterfly on his finger. His investigative spirit awakened rapidly. He wanted a microscope for Christmas, which enabled him to finally take a closer look at insects. “Then I read in a book about the large, nocturnal ground beetles along with a description of traps to catch them”. The boy made enquiries with his biology teacher. She sent him to the Natural History Museum in his hometown of Osnabrück. There, he got the traps and was soon able to present his catches to the experts. “That's how I got into the entomology scene as a student” recalls Assmann.

He obtained the German university entrance qualification and went on to study biology in Giessen and Münster where he continued to work on ground beetles. His doctoral thesis deals with population genetics. The entomologist wrote his postdoctoral thesis on animal ecology. Since 2001 he has been a professor of animal ecology at Leuphana and works on ground and dung beetles in various habitats. Assmann conducts research in the Middle East, China and the Carpathians. However, his work often takes him to the major natural history museums in Paris, London or Berlin. There, he looks at the so-called type specimens. On the basis of these animals, a species was described for the first time. The expert uses these records to compare and delimitate to the new type. Is the beetle's lip wider than that of the reference animals? Do the elytra have more dots? Does the pronotum have a more pronounced curvature?

“It's detective work”

Only by these steps Assmann can decide whether or not it is really a new species: “It's detective work”. But this traditional procedure is still necessary. “A DNA barcode now makes it possible to determine species. However, that procedure is not yet fully developed. In addition, you will always need a morphologically determined animal as a reference specimen in order to correctly assign the genetic code” Assmann explains. In addition, many of the data collected is now evaluated statistically as well. Assmann measures several animals to find a species-specific pattern. In addition, scientific photographs appear in the publication. A special camera photographs the beetles in different layer views to give the scientific community a precise impression of the new species. 

Last but not least, Assmann gives the new species a name. This denomination can be in honour of someone. In the case of the two new species of Lebistina, the scientist has chosen Anne Peters, a long-time technical employee, and Heinz-Otto Rehage, his entomological mentor from the Museum of Natural Sciences in Münster. Lebistina pertersae and Lebistina rehagei are now crawling through Africa.


Contact

Prof. Dr. Thorsten Aßmann
Universitätsallee 1, C13.033
21335 Lüneburg
Fon +49.4131.677-2840
Fax +49.4131.677-2808
thorsten.assmann@leuphana.de


Marietta Hülsmann, University Marketing. News from the university surrounding the areas of research, teaching and study can be sent to news@leuphana.de.