Biotech Updates

Study on Ladybirds Demonstrates No Detrimental Effects by Cry1Ac and Cry2Ab

July 22, 2011

Ladybird beetle (Coleomegilla maculata) is one of the predominant predators in various cropping systems. Both its larvae and adults forms feed on other small organisms like aphids and lepidopeteran larvae, as well as plant tissues. Thus, when ladybirds feed on Bt cotton, they are exposed to Cry proteins. This led Yunhe Li of Cornell University and colleagues to conduct a tritrophic bioassay to investigate the possible effect of Bt cotton on the fitness parameters of ladybirds.

Results showed that the survival, development time, adult weight, and fecundity of the ladybirds are similar on both ladybirds fed with Bt and non-Bt cotton. To further elucidate possible effects of the Bt proteins, the ladybirds were given artificial diets containing Cry proteins in larger concentrations (more than 10x) the normal amount in Bt cotton tissue. No significant differences were found between the ladybirds fed with high Bt protein content and the control. Thus, ladybirds are not sensitive to Cry1Ac and Cry2Ab in Bt cotton.

Read the open-access article at http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0022185/