Seasonal changes in the fatty acid profile of the tick Ixodes ricinus (Acari, Ixodidae).

Fatty acids (FAs) from nymphs, females and males of Ixodes ricinus were analysed by gas chromatography/mass spectrometry. Ticks were collected from May to October 2013. The most abundant FAs were 18:1, 18:0, 16:0 and 18:2 which are also dominant FAs of insects. Adults contained higher concentrations of FAs in general than nymphs because they contain more fat body and probably a thicker layer of epicuticular lipids. Larger quantities of FAs > 20 carbon atoms in the carboxylic chain were present in females, which generally show higher content of lipids essential for oogenesis, whereas there were similar amounts of 14-18 in both sexes. In September and October, ticks contained large concentrations of the majority of FAs except for 18:1, the most abundant one in ticks collected from May through August. Thus, most FAs, especially those with more than 20 C atoms, tend to increase at lower temperatures.