Project 5

Genetic determination and phenotypic plasticity of color polymorphisms in grasshoppers

Supervisors:
Prof. Dr. Holger Schielzeth (main supervisor)
Institute of Ecology and Evolution, Friedrich Schiller University Jena

Background:
All species are variable in coloration, but in some species, multiple discrete color variants coexist within local population. The maintenance of such color polymorphisms requires special ecological and evolutionary conditions. Otherwise: Why does not one variant succeed as the best adapted? Orthoptera (grasshoppers and bush-crickets) are exceptional in that about 1/3 of the species are color polymorphic – more than in any other large group of organisms. This calls for a general explanation.

It has long been believed that grasshoppers are able to change their body color during ontogeny. But mounting evidence shows that at least in some groups, color morphs are determined by simple Mendelian genetics. It is currently unknown which species (groups) are color changes and which show genetic determination without plasticity. Precisely this knowledge is knowledge is critical to understanding how Orthoptera maintain their extraordinary color diversity.

Project description:
The project will screen multiple species of Orthoptera for how their color morphs are determined during ontogeny. This involves breeding of species in the laboratory. Breeding facilities and protocols are well established at the Institute of Ecology and Evolution. For species with genetic determination, we will determine the exact mode of inheritance and how it has compares to other Orthoptera. This knowledge will give insights into how the color loci have evolved. For species with phenotypic plasticity in color, we will determine if there is a genetic basis do plasticity. This will shed light onto the interaction between genetics and the environment.

Candidate profile:
- Proactive, dynamic and curious
- Excellent communication and organizational skills
- Fluent in written and spoken English
- Willing and able to handle grasshoppers
- Experience in data analyses and R is desirable

Reading (optional):

Köhler, G. & Schielzeth, H. (2020). Green-brown polymorphism in alpine grasshoppers affects body temperature. Ecology and Evolution 10: 441-450. https://doi.org/10.1002/ece3.5908
Schielzeth, H. (2020). Phylogenetic, geographic and ecological distribution of a green-brown polymorphisms in European Orthopterans. bioRxiv https://doi.org/10.1101/2020.03.31.016915
Winter, G., Varma, M. & Schielzeth, H. (2021). Simple inheritance of color and pattern polymorphism in the steppe grasshopper Chorthippus dorsatus. Heredity 127: 66-78. https://doi.org/10.1038/s41437-021-00433-w