The impact of host plant chemistry on Maculinea arions choise of plant individuals for egg deposition

Text: Eva Grøndahl 2012-07-26

The genus Thymus, like many other Lamiaceae, is known for its production of aromatic oil as a protection against e.g. herbivory and drought. In thyme, a polymorphism exists with respect to the composition of these aromatic compounds (often referred to as “chemotypes”, or “chemical polymorphism”).

Maculinea arion,  The Large Blue butterfly, is dependent on the presence of thyme for egg deposition and as a food source. Moreover it has an obligate interaction with an ant species of the genus Myrmica.

The aim of this project is to uncover  the chemical polymorphism in Thymus serpyllum on the Swedish island Öland, where M. arion is relatively common. By analysing thyme leaf samples from plants chosen for egg deposition as well as randomly selected plants, we investigate whether the oil composition of “chosen” plants differ from random plants. Moreover, we sample random plants from sites where M. arion is known to occur, and compare these to samples from sites without M.arion. Leaf samples are analysed using gas chromatography.The chemical analyses are combined with registration of plant phenology and patch size.

Eva Grøndahl, PhD-student

University of Southern Denmark, Campusvej 55, DK-5230 Odense M.

Supervisor: Bodil K. Ehlers.

In collaboration with

professor Johan Ehrlén, University of Stockholm.