|since 2016||PhD student, Johannes Gutenberg-University Mainz
Preliminary title: „Causes and consequences of cuticular hydrocarbon diversification in parabiotic ants”
|2014 - 2016||M.Sc., Johannes Gutenberg-University Mainz
Thesis: „Acclimation of cuticular hydrocarbon profiles to desiccation stress in two sister species of the ant genus Myrmica“
|2011 – 2014||B.Sc., Johannes Gutenberg-University Mainz
Thesis: „Influence of temperature and humidity on the cuticular hydrocarbon profile of workers in Myrmica Rubra“
|2016||Collection of parabiotic ant species in French Guiana (8 weeks)|
|2015||Collection of Myrmica colonies around Freiburg, Germany (2 weeks)|
|2017||5th Central European Meeting of the IUSSI in Schöntal, Germany
Talk: „Distribution of parabiotic ant species from South America with highly diverse cuticular hydrocarbon profiles”
|2016||21st DZG Graduate Meeting Evolutionary Biology & Ecology in Greifswald, Germany
Talk: „Acclimation of cuticular hydrocarbon profiles to desiccation stress in two sister species of the ant genus Myrmica”
The cuticle of insects is covered with a thin layer of different chemical substances. In most species these are mainly cuticular hydrocarbons (CHC). These chemicals have two major functions: Primarily they serve as a barrier to cuticular water loss and prevent desiccation, which allows insects to survive even in dry areas. However, CHCs secondarily evolved multiple functions in chemical communication. Especially in social insects the CHCs are important as they indicate species- and colony membership, give information about the fertility status and inform nestmates about the task its bearer performs in the colony.
I am mainly interested in the question why the cuticular hydrocarbon profiles are so diverse and which factors influence their composition. This includes the detection of abiotic and biotic selection pressures, which evolutionary influence the CHC profile, but also environmental factors (like temperature, humidity or food conditions) which can change the profile within an organism’s phenotypic plasticity. With these aims I analyze the structure of cuticular hydrocarbons of ants using gas-chromatography mass-spectrometry (GC-MS), investigate their functions in the prevention of water loss and chemical communication as well as the genetic basis of the CHC biosynthesis.
Ants normally show either aggressive or submissive behavior in confrontations with other ant species. One exception are parabioses in tropical ants, where two species live together in a mutualistic association. In those the two different ant species can carry out interspecific trophallaxis, share the same chemical trails, exploit the same food sources and live together in one nest, while however keeping their brood separated. These associations always involve ants of the genus Crematogaster and a partner species which is often of the genus Camponotus. In addition to the unusual interspecific tolerance, such parabiotic ant species possess a high chemical diversity. This makes them interesting model organisms for the investigation of the evolution of cuticular hydrocarbon profiles and their influence on reproductive isolation, nestmate recognition and desiccation resistance.
We investigate the neotropical ant species Crematogaster levior and its parabiotic partner species Camponotus femoratus. Both have at least two different chemical morphs (chemotypes), which are chemically clearly distinguishable but morphologically difficult to distinguish. We are interested in the questions how many different chemotypes are present in our two model organisms, if these different chemotypes are reproductively isolated (i.e. if the chemotypes represent cryptic species), which genetic basis the differentiation of chemotypes has and which traits of the chemical profile are important in the recognition of intra- and interspecific nestmates. Therefore we will firstly conduct chemical analyses of the species’ CHC profiles using GC-MS. Secondly, we look at differential gene expression in the biochemical pathways of CHC synthesis to find the causes of the chemical differentiation using transcriptomic analyses. Thirdly, we will conduct behavioral observations with ants treated with different fractions of CHCs to find consequences of the high CHC diversity.
Sprenger PP, Hartke J, Feldmeyer B, Orivel J, Schmitt T, Menzel F. Influence of mutualistic lifestyle, mutualistic partner, and climate on cuticular hydrocarbonprofiles in parabiotic Ants. Journal of Chemical Ecology, in press.
Hartke J, Schell T, Jongepier E, Schmidt H, Sprenger PP, Paule J, Bornberg-Bauer E, Schmitt T, Menzel F, Pfenninger M, Feldmeyer B. Hybrid genome assembly of a neotropical mutualistic ant. Genome Biology and Evolution, in press.
Hartke J*, Sprenger PP*, Sahm J, Winterberg H, Orivel J, Baur H, Beuerle T, Schmitt T, Feldmeyer B*, Menzel F* (*authors contributed equally) Cuticular hydrocarbons as potential mediators of cryptic species divergence in a mutualistic ant association. Ecology and Evolution, in press.
Sprenger PP, Burkert LH, Abou B, Federle W, Menzel F (2018): Coping with the climate: Cuticular hydrocarbon acclimation of ants under constant and fluctuating conditions. Journal of Experimental Biology, doi: 10.1242/jeb.171488