Figure 8. Concentrations of ethanol (10, 30 and 50%) injected into the midguts affect spinning and pupation.

Ethanol solution at different concentrations was injected into the midguts of silkworm larvae (50 μl for each larva). (A) Percentage of death after ethanol injection. The number of dead larvae were counted at 24 h after injection. Each column represents the mean of measurements (±SE) from three biological replicates (at least 15 larvae for each treatment). (B) The lowest concentration of ethanol (10%) did not affect larval growth but did prevent spinning. There were no significant differences in body weight among different treatments during the feeding period. However, the weight of pre-pupae receiving the lowest concentration (10%) of ethanol injection during the feeding stage (V-2) was significantly higher than others. Each column represents the mean of measurements (±SE) from three biological replicates (at least 15 larvae for each treatment). (C–H) Morphology of cocoons and pupae receiving different treatments during the feeding stage (V-2) as indicated. (C,D) Naïve; (E,F) Water injection; (G,H) 10% ethanol injection. (C,E,G). Cocoons. Silkworms that received an ethanol injection into the midgut during the feeding stage (V-2) did not spin (G). (D,F,H) Pupae. Ethanol injection affected pupation. **p < 0.01.