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Impact of pollen grains from Bt transgenic corn on the growth and development of Chinese tussah silkworm, Antheraea pernyi (Lepidoptera: Saturniidae)

Li, W., Wu, K., Wang, X., Wang, G., Guo, Y.
Environmental entomology 2005 v.34 no.4 pp. 922-928
Zea mays, transgenic plants, Bacillus thuringiensis, crystal proteins, pollen, toxicity, nontarget organisms, Antheraea pernyi, mortality, insect growth, larval development, food conversion, risk assessment, China
The tussah silkworm, Antheraea pernyi (Lepidoptera: Saturniidae), is an important natural resource for the silk industry and has been cultured using wild host plants for >2,000 yr in China. To clarify whether there is any risk from pollen of Cry1Ab-containing corn varieties on this insect, the frequency of pollen dispersal and deposition of corn pollen near cornfields and impact on the development of tussah silkworm larvae were studied separately in the field and laboratory. The field survey showed that the pollen density was the highest inside the cornfield with a value of approximately equal to 1,000 grains/cm2. The pollen deposition rapidly declined with distance from the edge of the cornfield as expected in most cases. No significant differences were observed in the amounts of pollen deposited on glass slides positioned at different heights from the ground at each distance. In the laboratory bioassays, there were no significant differences in the larval mortality and weight of Chinese tussah silkworm between treatment with pollen grains from a transgenic corn line and a nontransgenic corn control at a density of 1,000 pollen grains/cm2. Also no significant negative impact was found for efficiency of conversion of digested food (ECD), efficiency of conversion of ingested food (ECI), and efficiency of approximate digestion of food (AD) at the level of 1,000 pollen grains/cm2. The results of this study suggest that the impact on the Chinese tussah silkworm of Bt corn pollen from the hybrid to be commercialized in China is negligible in the natural environment.