Seasonal changes in fatty acid composition of Eysarcoris inconspicuous (Herrich-Schaffer, 1844) (Heteroptera: Pentatomidae) adults

Abstract

1 * Summary The goal of the study was to investigate the role of phospholipid and triacylglycerol fatty acid compositional changes in Eysarcoris inconspicuous (Herrich- Schaffer, 1844) (Heteroptera: Pentatomidae) with respect to seasonal changes. E. inconspicuous adults were collected from Diyarbakir, Turkey in 2007-2008. The fatty acid compositions of phospholipid and triacylglycerol fractions that were extracted from whole-body of adult E. inconspicuous were isolated and analyzed using gas chromatography and gas chromatography-mass spectrometry. Qualitative analysis has revealed the presence of 15 fatty acids during most of the months. The major components were C16 and C18 saturated and unsaturated components which are ubiquitous in most animal species. In addition to these components, three odd-chain (C13:0), (C15:0), (C17:0), and prostaglandin precursor fatty acids were found. The fatty acid profiles of phospholipids and triacylglycerols have some diferences. In contrast to triacylglycerol fraction, linolenic acid and C20 polyunsaturated fatty acids increased during autumn and winter in phospholipid fraction were detected. The unsaturated fatty acid to saturated fatty acid ratio significantly increased in both fractions but the increase was dramatic in phospholipid fraction during autumn, and reaches its maximum level in january and february, when outdoor temperatures are low. Thus, temperature seems to play an important role in seasonal variation of lipid metabolism of E. inconspicuous. Preventing cellular damage due to low temperatures is a major challenge for insects. These findings indicate that E. inconspicuous can modify its fatty acid composition in response to changes in environmental conditions.