The Japanese ladybirds, Coccinula crotchi and Coccinula sinensis, are infected with very closely related strains of male-killing Flavobacterium  

作　　者：Sherif Elnagdy Susan Messing Michael E. N. Majerus 

机构地区：[1]Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK [2]Botany Department, Faculty of Science, Cairo University, Giza, Egypt, University of Rochester, Rochester, New York, USA [3]Department of Biostatistics and Computational Biology, University of Rochester, Rochester, New York, USA

出　　处：《Insect Science》2014年第6期699-706,共8页昆虫科学（英文版）

摘　　要：Male-killing is 1 of 4 known strategies that inherited parasitic endosymbionts have evolved to manipulate their host＇s reproduction. In early male-killing, infected male offspring are killed early in embryogenesis. Within the Insecta, male-killing bacteria have been found in a wide range of hosts. The Coccinellidae families of beetles, better known as ladybirds, are particularly prone to male-killer invasion. In samples of the coccinellid, Coc- cinula crotchi, from Japan, a new male-killing bacterium was revealed by phenotypic assay. Molecular genetic analysis revealed the identity to be a tetracycline-sensitive Flavobac- terium that causes female-biased offspring sex ratio. Furthermore, that Flavobacterium strain was found to be closely related to the Flavobacterium causing male-killing in the congeneric Japanese coccinellid, Coccinula sinensis, which was collected from the same region. However, we found slightly different Flavobacterium strains infecting C. sinen- sis from regions with different environmental conditions. This may be an indication of horizontal transmission of male-killing Flavobacterium between these 2 ladybird spices. Finally, environmental conditions may affect the spread of male-killing bacteria among their hosts.Male-killing is 1 of 4 known strategies that inherited parasitic endosymbionts have evolved to manipulate their host＇s reproduction. In early male-killing, infected male offspring are killed early in embryogenesis. Within the Insecta, male-killing bacteria have been found in a wide range of hosts. The Coccinellidae families of beetles, better known as ladybirds, are particularly prone to male-killer invasion. In samples of the coccinellid, Coc- cinula crotchi, from Japan, a new male-killing bacterium was revealed by phenotypic assay. Molecular genetic analysis revealed the identity to be a tetracycline-sensitive Flavobac- terium that causes female-biased offspring sex ratio. Furthermore, that Flavobacterium strain was found to be closely related to the Flavobacterium causing male-killing in the congeneric Japanese coccinellid, Coccinula sinensis, which was collected from the same region. However, we found slightly different Flavobacterium strains infecting C. sinen- sis from regions with different environmental conditions. This may be an indication of horizontal transmission of male-killing Flavobacterium between these 2 ladybird spices. Finally, environmental conditions may affect the spread of male-killing bacteria among their hosts.

关 键 词：Coccinula crotchi Coccinula sinensis ENDOSYMBIONTS FLAVOBACTERIUM inherited bacteria MALE-KILLING sex ratio distorter 

分 类 号：S567.35[农业科学—中草药栽培] X172[农业科学—作物学]