Phytophagous insect diversity is thought to be the result of host specialization process. The evolution of insect host specialization takes place by the action of factors increasing or reducing diet breadth. However, mechanisms affecting insect diet breadth are far from being totally understood. In the present work, diet breadth patterns of species of the aphid genus Neuquenaphis (Hemiptera: Aphididae) feeding on Nothofagus species (southern beeches) in central-south of Chile are described. In order to investigate causes underlying these patterns, phenotypic and genotypic variation associated with diet breadth was study. We have found that species with restricted diet breadth are more selective during host choice experiments, have lower performance on con-generic alternatives host plants, and have higher genetic differentiation than wider diet breadth species. Intra-specific comparisons showed that within one locality, the generalist Neuquenaphis edwardsi showed host-based phenotypic variation that seems to be caused by phenotypic plasticity rather than by host-based genetic differentiation. The potential for host race formation in this aphid system is discussed.
Species 1: Homoptera Aphididae Neuquenaphis
Keywords: aphids, diet breadth
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