Jing Li, Brad S. Populations show genotype-by-environment variation in voltinism, such that populations with a single generation univoltine are fixed in Northern China where growing seasons are short.
In contrast, a mitochondrial haplotype network identified 4 distinct clusters, where This study suggests that gene flow among O. Haplotype variation may be due to random genetic drift resulting from partial reproductive isolation between univoltine and multivoltine O. Such reproductive isolation might impact the potential spread of alleles that confer resistance to transgenic maize in China.
Insects feeding on cultivated maize, Zea mays L. The geographic range of O. The capacity of O. Kojima et al. Conventional methods for the suppression of O. More recently, transgenic maize varieties that express insecticidal crystalline Cry toxins derived from Bacillus thuringiensis Bt βreferred to as Bt maizeβstarted to be commercialized in the mids Ferry et al. So far, reduced efficacy of Bt crops due to field resistance has been documented in 4 pests: Spodoptera frugiperda to Cry1F maize Matten ; Storer et al.
The susceptibilities of O. Feeding damage caused by O. An estimated fold decrease in susceptibility to the Cry1Ac toxin occurred in O. Hence, laboratory resistance of Ostrinia populations has raised concerns regarding the sustainability of Bt technologies. Adult dispersal likely has a strong influence on the evolution of resistance. Theoretically, non- Bt plants serve as a refuge in which large numbers of susceptible individuals will develop, and the resulting moths will mate at random with rare homozygous resistant moths that might emerge from Bt maize fields.
The rate of gene flow of susceptible moths greatly depends on the dispersal behavior of adults. Laboratory studies of potential flight distances indicated that male and female O. However, large proportions of individuals are never recaptured and make these results hard to interpret. Additionally, the use of light or pheromone traps may potentially attract individuals and prevent them from dispersing normally. Finally, a given dispersal distance or probability will have a different impact depending on whether it occurs before or after mating Dalecky et al.
