Comparative Analysis of Epicuticular Lipids in and : A Possible Role in Susceptibility to Entomopathogenic Fungi.

Cuticular lipids protect insects from desiccation and may determine resistance to fungal pathogens. Nonetheless, the trade-off between these lipid functions is still poorly understood. The migratory locust and the Italian locust have dissimilar hygrothermal preferences: inhabits areas near water bodies with a reed bed, and exploits a wide range of habitats and prefers steppes and semideserts with the predominance of sagebrushes. This paper presents significant differences between these species' nymphs in epicuticular lipid composition (according to gas chromatography with mass spectrometry) and in susceptibility to and . The main differences in lipid composition are shifts to longer chain and branched hydrocarbons (di- and trimethylalkanes) in compared to . also has a slightly higher -alkane content. Fatty acids showed low concentrations in the extracts, and has a wider range of fatty acids than does. Susceptibility to and the number of conidia adhering to the cuticle proved to be significantly higher in , although conidia germination percentages on epicuticular extracts did not differ between the species. We propose that the hydrocarbon composition of may be an adaptation to a wide range of habitats including arid ones but may make the cuticle more hospitable for fungi.