β-carotene and Bacillus thuringiensis insecticidal protein differentially modulate feeding behaviour, mortality and physiology of European corn borer (Ostrinia nubilalis)
Fig 2
Food choices of Ostrinia nubilalis larvae when β-carotene is incorporated into Bt and non-Bt diets.
β-carotene (denoted as β) was added to semi-artificial diets with Bt protein or without (Non-Bt), then offered to neonate (A, C) and fifth-instar (B, D) larvae. Sixty individuals per instar were tested (n = 60), and their location (on or off diet) were recorded at four time points (6 h, 1, 2, and 5 d). Each bar displays number of larvae on each diet. Off-diet or dead larvae were excluded from the analysis; their counts are shown next to each bar under ‘No choice’ and ‘Mortality’, respectively. Asterisks indicate significant differences between diets (X2, *P = 0.05, **P = 0.01, ***P < 0.001). NS, not significant. See the Materials and Methods section for detailed diet components.