Effects of Bt cotton on biological characteristics of Macrolophus pygmeus Rambur (Hem.: Miridae)

Study of the effects of genetically modified plants on non-target arthropods, is one of the most important research on transgenic plants safety. These plants are able to affect on natural enemies, directly and/or indirectly. So, in this study, the effect of feeding on Bt cotton and prey (Bemisia tabaci Gennadius) reared on Bt cotton was determined on predatory bug, Macrolophus pygmeus Rambur. Four diets including Bt-cotton Bemisia tabaci (first group), non Bt-cotton Bemisia tabaci (second group), Bt-cotton (third group), non Bt-cotton (forth group) were used in this experiment. The results showed that Bt-cotton significantly affected development time and fecundity of the predator. Developmental times of nymphs in the first, second, third and fourth groups were estimated to be 19.85±0.32, 16.08±0.24, 29.42±0.45 and 23.11±0.23 days, respectively. In addition, mean number of eggs laid in the non Bt-cotton Bemisia tabaci treatment were significantly more than other groups (32.778±0.97), although no significant differences were found on fecundity between Bt-cotton and non Bt-cotton treatments. According to the obtained results, the Bt-cotton potentially could have negative effect on the biological parameters of M. pygmeaus severely and applying transgenic plants as one of integrated pest management agent, needs still more experiments and attentions.