Neutral lipid fatty acid composition as trait and constraint in Collembola evolution

3 years ago

Neutral lipid fatty acid composition as trait and constraint in Collembola evolution

Philipp Sandmann, Ina Schaefer, Stefan Scheu, Ting-Wen Chen

Functional traits determine the occurrence of species along environmental gradients and their coexistence with other species. Understanding how traits evolved among coexisting species helps to infer community assembly processes. We propose fatty acid composition in consumer tissue as a functional trait related to both food resources and physiological functions of species. We measured phylogenetic signal in fatty acid profiles of 13 field-sampled Collembola (springtail) species and then combined the data with published fatty acid profiles of another 24 species. Collembola fatty acid profiles generally showed phylogenetic signal, with related species resembling each other. Long-chain polyunsaturated fatty acids, related to physiological functions, demonstrated phylogenetic signal. In contrast, most food resource biomarker fatty acids and the ratios between bacterial, fungal, and plant biomarker fatty acids exhibited no phylogenetic signal. Presumably, fatty acids related to physiological functions have been constrained during Collembola evolutionary history: Species with close phylogenetic affinity experienced similar environments during divergence, while niche partitioning in food resources among closely related species favored species coexistence. Measuring phylogenetic signal in ecologically relevant traits of coexisting species provides an evolutionary perspective to contemporary assembly processes of ecological communities. Integrating phylogenetic comparative methods with community phylogenetic and trait-based approaches may compensate for the limitations of each method when used alone and improve understanding of processes driving and maintaining assembly patterns. We propose fatty acid compositions in consumers’ tissues as a functional trait which relates to both food resources and physiological functions of species. We inspected phylogenetic signals in fatty acid profiles from 13 field-collected Collembola species and 37 Collembola species compiled from the literature. Long-chain polyunsaturated fatty acids demonstrated phylogenetic signal that presumably suggest evolutionary constraint, while most food resource biomarker fatty acids exhibited phylogenetic lability that may imply niche partitioning in closely related species.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/ece3.3472