Dr. Tobias Engl
Institute of Organismic and Molecular Evolution
55128 Mainz, Germany
phone: +49 - (0) 6131 - 39 23572
fax: +49 - (0) 6131 - 39 23731
Like all animals, insects can interact with various microorganisms in a mutualistic or antagonistic manner. I am interested in both the evolutionary and functional aspects of these symbiotic relationships in different insect groups, including coleoptera and hymenoptera.
A surprising number of grain pest beetles live in symbiotic associations with bacteria or yeasts that supply their host with variable nutrients like amino acids and vitamins including both essential but also non-essential amino acids. One major characteristic of beetles that is influenced by the supplementation of non-essential amino acids is their cuticle, which regulates also the evaporation of water, an important factor for these beetles as their major habitat, grain and other stored products, is usually quite dry. We could show that the symbiosis of Bacteroidetes bacteria with the saw toothed grain beetle, Oryzaephilus surinamensis, supports the cuticle synthesis and thereby has a significant impact on the beetle survival and establishment in these conditions. I currently investigate how this symbiosis influences the physiology, behavior, ecology and evolution of O. surinamensis and several Bostrichid beetles. To test some of these aspects of symbiotic associations I also use other model systems, partially in collaborations, including Anobiids, Cucuujiolids and several flies. In addition to state of the art molecular techniques like quantitative PCR, Fluorescence in situ hybridization, genome and transcriptome analyses I use bioassays to compare the fitness of beetle populations associated with their natural symbiont with populations whose symbionts have been experimentally removed.
My work on beewolves, mainly the European beewolf, Philanthus triangulum, focusses more on the chemistry of the interaction with their defensive Streptomyces symbionts and with detrimental mold fungi. Beewolves sterilize their brood cell with nitric oxide, a highly reactive radical, which not only suppresses mold growth, but also exerts high pressure on the symbiont. The symbionts on the other hand provide important protection during hibernation of the larvae and metamorphosis by impregnating the cocoon with a conserved cocktail of antibiotics that serves as a combination prophylaxis against soil molds. We want to elucidate the symbionts’ physiological reaction to the repeated nitric oxide exposition as well as the evolutionary consequences of the adaptation to this challenging life style. We are further interested in the long-term use of the prophylactic antibiotic cocktail in a natural system, especially how diverse and variable such a natural blend over several beewolf species is, but also how different components interact with each other, regarding effectiveness against single strains and the spectrum of inhibited mold fungi. To this end, we apply various biotests and molecular biology methods as well as also modern, highly sensitive analytical chemistry including coupled gas chromatography – mass spectrometry (GC-MS), high performance liquid chromatography – mass spectrometry (HPLC-MS) and, in cooperation with the MPI for Chemical Ecology in Jena, mass-spectrometry based proteome analysis.
As to future projects, I am interested in how other ground nesting insects, mainly hymenoptera, deal with detrimental soil microbes.
Some of this work is done in international cooperations with:
John McCutcheon, University of Montana
Takema Fukatsu, AIST Tsukuba
Cornel Adler, JKI Berlin
Abdelaziz Heddi, Anna Zaidmann, Severine Balmand, INRA Lyon
Erhard Strohm, Universität Regensburg
Ales Svatos, MP-ICE Jena
Wolfgang Miller, Medizinische Universität Wien
Daniela Schneider, Yale School of Medicine
Karen Kapheim, Utah State University
Jaakko Mattila, Finnish Museum of Natural History
Philipp Bauer, Landwirtschaftliches Technologiezentrum Augustenburg / Universität Hohenheim