title: Competitive ability and fitness differences between two introduced populations of the invasive whitefly Bemisia tabaci Q in China.
abstract: BACKGROUND
  Our long-term field survey revealed that the Cardinium infection rate in Bemisia tabaci Q (also known as biotype Q) population was low in Shandong, China over the past few years. We hypothesize that (1) the Cardinium-infected (C+) B. tabaci Q population cannot efficiently compete with the Cardinium-uninfected (C-) B. tabaci Q population; (2) no reproductive isolation may have occurred between C+ and C-; and (3) the C- population has higher fitness than the C+ population.
  
  
  RESULTS
  To reveal the differences in competitive ability and fitness between the two introduced populations (C+ and C-), competition between C+ and C- was examined over several generations. Subsequently, the reproductive isolation between C+ and C- was studied by crossing C+ with C- individuals, and the fitnesses of C+ and C- populations were compared using a two-sex life table method. Our results demonstrate that the competitive ability of the C+ whiteflies was weaker than that of C-. There is that no reproductive isolation occurred between the two populations and the C- population had higher fitness than the C+ population.
  
  
  CONCLUSIONS
  The competitive ability and fitness differences of two populations may explain why C- whitefly populations have been dominant during the past few years in Shandong, China. However, the potential role Cardinium plays in whitefly should be further explored.
authors.affiliation: Key Lab of Integrated Crop Pest Management of Shandong Province, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, China.
authors.forename: Yi-Wei
authors.initials: YW
authors.lastname: Fang
authors.affiliation: Key Lab of Integrated Crop Pest Management of Shandong Province, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, China.
authors.forename: Ling-Yun
authors.initials: LY
authors.lastname: Liu
authors.affiliation: Key Lab of Integrated Crop Pest Management of Shandong Province, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, China.
authors.forename: Hua-Li
authors.initials: HL
authors.lastname: Zhang
authors.affiliation: Key Lab of Integrated Crop Pest Management of Shandong Province, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, China.
authors.forename: De-Feng
authors.initials: DF
authors.lastname: Jiang
authors.affiliation: Key Lab of Integrated Crop Pest Management of Shandong Province, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Chu
mesh_terms: D000818:Animals; D041963:Bacteroidetes / Q000502:physiology; D002681:China; D003163:Competitive Behavior; D003433:Crosses, Genetic; D005260:Female; D017344:Genes, Insect; D056084:Genetic Fitness; D006430:Hemiptera / Q000235:genetics / Q000254:growth & development / Q000382:microbiology / Q000502:physiology*; D058865:Introduced Species; D008018:Life Cycle Stages; D008297:Male; D012098:Reproduction; D012744:Sex Ratio; D016019:Survival Analysis