Figure 1.
Correlations between N and P concentrations in grasshopper body (a), frass (b), and food plants (c) of grasshopper Oedaleus asiaticus.
Figure 2.
Responses of N and P contents and N:P stoichiometry, of food plants (a–c), grasshopper body (d–f) and frass (g–i), to increasing grasshopper density.
Error bars indicate ±1 SE. In (a), a strong negative relationship was found between host plant N concentrations and grasshopper density (ANOVA: r2 = 0.93, F = 51.16, P = 0.002) and yielded the following equation: y = −0.13 x+14.52. In (b), a strong negative relationship was found between host plant N concentrations and grasshopper density (ANOVA: r2 = 0.86, F = 23.59, P = 0.008) and yielded the following equation: y = −0.01 x+1.17. In (h), a marginally negative relationship was found between frass P concentrations and grasshopper density (ANOVA: r2 = 0.65, F = 5.69, P = 0.097) and yielded the following equation: y = −0.025 x+2.14.
Table 1.
Results (F and P values) of one-way ANOVAs on the effects of grasshopper density on N:P ratio of food plant, grasshopper body and frass, corresponding to Figure 2.
Figure 3.
The effects of food plant N:P stoichiometry on N concentrations, P concentrations, N:P ratios in grasshopper body and frass.
Error bars indicate ±1 SE. In (e), a strong positive relationship was found between frass and food plant P concentrations (ANOVA: r2 = 0.85, F = 17.65, P = 0.025) and yielded the following equation: y = 3.13 x−1.43.
Figure 4.
The relationships between female and male body size (expressed by body dry weight) and experimental density in grasshopper Oedaleus asiaticus.
Error bars indicate ±1 SE. In (a), a negative relationship was found between female body size and grasshopper density (ANOVA: r2 = 0.80, F = 12.26, P = 0.04) and yielded the following equation: y = −0.0016 x+0.274. In (b), a negative relationship was found between male body size and grasshopper density (ANOVA: r2 = 0.78, F = 10.65, P = 0.047) and yielded the following equation: y = −0.0004 x+0.085.