Increased Vigor in Whitefly (Homoptera: Aleyrodidae) Associated with Bifenthrin-Resistant Males

In crosses of bifenthrin-resistant and susceptible populations of the silverleaf whitefly, Bemisia argentifolii Bellows & Perring or b-strain Bemisia tabaci Gennadius, we found that net reproduction (R_o) was significantly different between the parental populations and “F₁, male” backcrossed populations with approximately a two-fold increase in R_o occurring in the backcrosses. Also, the level of adult emergence was positively related to the changes of R_o in B. argentifolii. The average longevity of adults, number of eggs adults oviposited, and percentage female in the progenies changed across populations, with some factors enhancing reproduction in the bifenthrin resistant backcross. These results confirm that, not only does increased vigor occur in bifenthrin-resistant whitefly backcrosses, but also that males of cross-mated females differ from males of the parent population in their ability to induce increased vigor in the backcross. This is the first evidence that whitefly males from mated and unmated females could be genetically distinct.