title: Dynamics of the endosymbiont Rickettsia in an insect pest.
abstract: A new heritable bacterial association can bring a fresh set of molecular capabilities, providing an insect host with an almost instantaneous genome extension. Increasingly acknowledged as agents of rapid evolution, inherited microbes remain underappreciated players in pest management programs. A Rickettsia bacterium was tracked sweeping through populations of an invasive whitefly provisionally described as the "B" or "MEAM1" of the Bemisia tabaci species complex, in the southwestern USA. In this population, Rickettsia provides strong fitness benefits and distorts whitefly sex ratios under laboratory conditions. In contrast, whiteflies in Israel show few apparent fitness benefits from Rickettsia under laboratory conditions, only slightly decreasing development time. A survey of B. tabaci B samples revealed the distribution of Rickettsia across the cotton-growing regions of Israel and the USA. Thirteen sites from Israel and 22 sites from the USA were sampled. Across the USA, Rickettsia frequencies were heterogeneous among regions, but were generally very high, whereas in Israel, the infection rates were lower and declining. The distinct outcomes of Rickettsia infection in these two countries conform to previously reported phenotypic differences. Intermediate frequencies in some areas in both countries may indicate a cost to infection in certain environments or that the frequencies are in flux. This suggests underlying geographic differences in the interactions between bacterial symbionts and this serious agricultural pest.
authors.affiliation: Graduate Interdisciplinary Program in Entomology and Insect Science, University of Arizona, 410 Forbes, Tucson, AZ, 85721, USA, bcass@email.arizona.edu.
authors.forename: Bodil N
authors.initials: BN
authors.lastname: Cass
authors.forename: Rachel
authors.initials: R
authors.lastname: Yallouz
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Bondy
authors.forename: Netta
authors.initials: N
authors.lastname: Mozes-Daube
authors.forename: A Rami
authors.initials: AR
authors.lastname: Horowitz
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Kelly
authors.forename: Einat
authors.initials: E
authors.lastname: Zchori-Fein
authors.forename: Martha S
authors.initials: MS
authors.lastname: Hunter
mesh_terms: D000818:Animals; D017931:DNA Primers / Q000235:genetics; D056084:Genetic Fitness / Q000235:genetics; D014644:Genetic Variation; D005843:Geography; D006430:Hemiptera / Q000382:microbiology*; D007300:Insect Control / Q000379:methods*; D058865:Introduced Species; D007557:Israel; D016015:Logistic Models; D018895:Microsatellite Repeats / Q000235:genetics; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012281:Rickettsia / Q000235:genetics*; D012744:Sex Ratio; D015206:Southwestern United States; D013559:Symbiosis; D013997:Time Factors
chemical_list: D017931:DNA Primers; D012336:RNA, Ribosomal, 16S