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Free keywords:
carbon 13; C₃ plants; C₄ plants; grasshoppers; insect herbivory; millipedes; photosynthetic pathways
Abstract:
C₄ plant species were proposed to generally represent inferior food sources compared to C₃ plants thus are avoided by herbivores, particularly insects, This was tested in semi-aquatic and terrestrial arthropods from Amazonian river-floodplains by carbon isotope discrimination (δ¹³C). Two semi-aquatic grasshopper species (Stenacris f. fissicauda, Tucayaca gracilis-Actididae) obtain their carbon during development from specific C₄ macrophytes and two semi-aquatic species (Cornops aquaticum-Acrididae, Paulinia acuminata-Pauliniidae) from Specific C₃ macrophytes. The terrestrial millipede Mestosoma hylaeicum (Paradoxosomatidae) obtains about 45% of its carbon from roots of one C₄ macrophyte during the development of immatures whereas adults use other food sources, including C₃ trees. Results suggest, that (1) both C₄ and C₃ plants represent distinct hosts for terrestrial arthropods in Amazonia; (2) immatures may use plant species with a different photosynthetic pathway than adults.
