Abstract

In recent years the B biotype of Bemisia tabaci has been an invasive insect in China. To elucidate its potential to replace a non-B biotype of B. tabaci, native to Zhejiang, China, we reared both biotypes on various host plants in a series of laboratory experiments to observe the changes in their relative proportions. On cotton, when the two biotypes began competition in equal numbers, the non-B biotype was completely displaced by the B biotype after six generations, whereas on squash, the non-B biotype was completely dis-placed by the B biotype after only two generations. Even when the competition started with 87% of non-B biotype and 13% of B biotype in numbers, the non-B biotype was completely displaced in 225 days. The re-sults showed that the invasive B biotype has the capacity to displace the non-B biotype in a short period of time. A preliminary analysis indicates that, apart from the advantage of a wider host range of the B biotype over that of non-B biotypes, a stronger innate capacity for competition is another important factor in the suc-cessful invasion of the B biotype and its displacement of the native biotype.