title: Lack of fitness costs associated with pyriproxyfen resistance in the B biotype of Bemisia tabaci.
abstract: BACKGROUND
  The insect growth regulator pyriproxyfen has provided effective control of the whitefly Bemisia tabaci Gennadius in many countries. Here, whether or not fitness costs were associated with pyriproxyfen resistance in a laboratory-selected resistant strain (QC02-R) of the B biotype was determined.
  
  
  RESULTS
  Mortality caused by pyriproxyfen and fitness traits over time were measured in unselected and selected hybrid strains, which were created by crossing individuals of the resistant strain with individuals of a susceptible strain. Fitness costs were not associated with resistance in QC02-R, as mortality caused by pyriproxyfen did not increase over time in unselected hybrid strains and fitness traits were similar in unselected and selected hybrid strains. Using a new method to examine the inheritance of resistance, based on data from fitness cost experiments, it was estimated that pyriproxyfen resistance is controlled by two loci in the QC02-R strain.
  
  
  CONCLUSIONS
  The lack of fitness costs associated with pyriproxyfen resistance could promote the evolution of resistance in field populations with similar traits to QC02-R.
authors.affiliation: Department of Entomology, University of Arizona, Tucson, AZ 85721, USA. dcrowder@ag.arizona.edu
authors.forename: David W
authors.initials: DW
authors.lastname: Crowder
authors.forename: Christa
authors.initials: C
authors.lastname: Ellers-Kirk
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Tabashnik
authors.forename: Yves
authors.initials: Y
authors.lastname: Carrière
mesh_terms: D000818:Animals; D002678:Chimera; D003433:Crosses, Genetic; D005260:Female; D006430:Hemiptera / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D007305:Insecticide Resistance; D007605:Juvenile Hormones / Q000494:pharmacology*; D008297:Male; D011725:Pyridines / Q000494:pharmacology*
chemical_list: D007605:Juvenile Hormones; D011725:Pyridines; C055613:pyriproxyfen