Tribolium castaneum - the red flour beetle

Apart from the fly Drosophila, the red flour beetle Tribolium is the most developed model system within arthropods. Its major strength lies in the robust reverse genetics via RNAi gene kock-down in combination with the recently published genomic sequence.

Red flour beetle Tribolium castaneum

Tribolium castaneum, the red flour beetle, is a basal holometabolous insect. For comparative purposes, it holds a crucial position between the ancestral hemimetabolous and the most derived holometabolous insects. In contrast to the fly Drosophila, Tribolium displays more "typical" modes of development in several respects: posterior segments are formed one after the other from a posterior growth zone, the embryo develops appendages directly (and not via leg discs) and the larval head develops appendages (in contrast to the extremely derived head morphology of the Drosophila larva). As a corn pest Tribolium has also found attention in pestizide resistance research.

Tribolium castaneum - a convenient model system

Beetle larva (top) and fly larva (bottom) © Klingler

Tribolium is easy to rear in large amounts, constantly produces offspring and is amenable to various histological and molecular manipulations: Gene function can be knocked out by zygotic RNAi or morpholino oligo injection. Furthermore, we have shown that injecting females with double stranded RNA knocks down gene function in the offspring (parental RNAi). This allows for the study of gene expression or application of standard histological methods to large amounts of knock-down embryos that have not been hurt by injection. Also genomic RNAi screens are feasable with this technique. In addition, transgenes can easily be introduced to the beetle genome using the piggyBac, Mariner or Minos transposons using a marker system that is widely applicable within the animal kingdom. A screen for EMS induced mutations has been carried out as well as initial insertional mutagenesis. Finally, the genomic sequence of Tribolium has been released in 2005.

Finally, we have established heat shock mediated misexpression of genes and created a transgenic line with nuclear localized GFP. The latter will allow in vivo imaging and fate mapping experiments.

This "tool set" for Tribolium research will make it possible to deeply understand developmental processes in a "typical" holometabolous insect and will allow comparisions of Tribolium and Drosophila genetics to quite some depth. Importantly, processes that cannot be studied in Drosophila can be investigated using the red flour beetle.

© Gregor Bucher, last update: september 06