How do beetles taste

Beetles smell with their mouth and antennae

In addition to the antennae, the mouth probes of the rice flour beetle also contain numerous nerve cells (colored green) that are used to perceive chemical signals. (Photo: Philipps-Universität Marburg / AG Schachtner. The image may only be used in connection with reporting on the associated scientific publication)

Beetles use antennae and mouthparts to sense both smell and taste. This is what biologists from Marburg and Göttingen found out by precisely describing the head and brain structures of beetles and demonstrating the activity of the genes that enable smell and taste. The team reports on its results in the current online edition of the journal BMC Biology.

The sense of smell is of great importance for the survival and reproduction of most animals: They follow scents to food sources and mating partners, among other things. "As the largest group of insects, beetles are of enormous ecological and economic importance," emphasizes co-author Professor Dr. Joachim Schachtner, who teaches neurobiology at the Philipps University in Marburg. “Nevertheless, most of the specialist colleagues have so far been using other model organisms when they deal with the insects' sense of smell, such as flies, butterflies or honey bees,” adds co-author Professor Dr. Ernst A. Wimmer, developmental biologist from the Georg-August-Universität Göttingen.

For the current study, the researchers instead examined the red-brown rice flour beetle Tribolium castaneum. In addition to the antennas, Tribolium has two pairs of mouth sensors, so-called palps. Science has long known that the antennae of insects are mainly responsible for the perception of scents and the mouth sensors are mainly responsible for taste. The team found that there are many active genes in the palps that contain blueprints for olfactory receptors. "This finding shows that the beetle's palps are more important for the sense of smell than other insects examined so far," explains Dr. Stefan Dippel, one of the two first authors of the study.

In addition, taste receptors are evenly distributed across antennae and mouthparts. "Antennas on the one hand and mouthparts on the other hand are therefore not exclusively responsible for either tasting or smelling the beetles," explains Dr. Martin Kollmann, who shares first authorship with Dippel.

The scientists also examined where the scent information is processed. They discovered a previously unknown region of the nervous system in the sub-pharynx area, which picks up olfactory signals from the mouthparts, while the corresponding signals from the antennae are processed in the brain, as is usual in other insects. “The sensory impressions of the mouthparts and the antennae are initially recorded separately in the central nervous system,” says Wimmer, explaining the findings, and Schachtner emphasizes: “Contrary to previous opinion, the antennae and the mouthparts seem to play an important role in the beetles' olfactory perception. Exactly what role this is now needs to be researched further. "

Professor Dr. Joachim Schachtner teaches neurobiology at the Philipps University; since 2010 he has also been Vice President for Information and Quality Management. Professor Dr. Ernst A. Wimmer heads the department for developmental biology at the Georg-August-Universität Göttingen. The German Research Foundation funded the work on the present study through its priority program 1392 (“Integrative Analysis of Olfaction”).

Original publication: Stefan Dippel, Martin Kollmann & al .: Morphological and Transcriptomic Analysis of a Beetle Chemosensory System Reveals a Gnathal Olfactory Center, BMC Biology 2016

http://bmcbiol.biomedcentral.com/articles/10.1186/s12915-016-0304-z

 

Additional Information:

Contact Person:

Professor Dr. Joachim Schachtner,
Department of Biology
Philipps University of Marburg
Tel .: 06421 28-23414
Email: [email protected]
Homepage: www.uni-marburg.de/fb17/fachgebiete/tierphysio/neurobiologie/ag-schachtner

Professor Dr. Ernst A. Wimmer,
Johann Friedrich Blumenbach Institute
for zoology and anthropology
Georg-August-University Goettingen
Tel .: 0551-39 22 888
Email: [email protected]
Homepage: www.uni-goettingen.de/de/43240.html