The isotopic discrimination factors between the tissues of caterpillars (plus ‘+’ signs, dotted line) and moths (open circles, barred line) decreased significantly with the δD value of plant tissues according to a shallow common slope.

<p>Note that the discrimination factors for plants, caterpillars and moths differed significantly from one another (Tukey's test, p<0.05). The horizontal reference line represents ΔD = 0.