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Figure 3: Differences among four Onthophagus species in the range of nutrition-mediated plasticity in male horn expression. Shown are the scaling relationships between body size (X-axis) and horn length (Y-axis). Patterns of nutritional plasticity in horn expression range from minimal and linear (O. sagittarius) and modestly sigmoidal (O. gazella) to strongly sigmoidal with species-specific differences in amplitude (O. taurus and O. nigriventris).