Discovery and identification of a male-killing agent in the Japanese ladybird <it>Propylea japonica </it>(Coleoptera: Coccinellidae)
<p>Abstract</p> <p>Background</p> <p>Endosymbionts that manipulate the reproduction of their hosts have been reported widely in invertebrates. One such group of endosymbionts is the male-killers. To date all male-killers reported are bacterial in nature, but comprise a...
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| Format: | Article |
| Language: | English |
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BMC
2010-02-01
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| Series: | BMC Evolutionary Biology |
| Online Access: | http://www.biomedcentral.com/1471-2148/10/37 |
| _version_ | 1818570033739071488 |
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| author | Majerus Michael EN Majerus Tamsin MO |
| author_facet | Majerus Michael EN Majerus Tamsin MO |
| author_sort | Majerus Michael EN |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Endosymbionts that manipulate the reproduction of their hosts have been reported widely in invertebrates. One such group of endosymbionts is the male-killers. To date all male-killers reported are bacterial in nature, but comprise a diverse group. Ladybirds have been described as a model system for the study of male-killing, which has been reported in multiple species from widespread geographic locations. Whilst criteria of low egg hatch-rate and female-biased progenic sex ratio have been used to identify female hosts of male-killers, variation in vertical transmission efficiency and host genetic factors may result in variation in these phenotypic indicators of male-killer presence. Molecular identification of bacteria and screening for bacterial presence provide us with a more accurate method than breeding data alone to link the presence of the bacteria to the male-killing phenotype. In addition, by identifying the bacteria responsible we may find evidence for horizontal transfer between endosymbiont hosts and can gain insight into the evolutionary origins of male-killing. Phylogenetic placement of male-killing bacteria will allow us to address the question of whether male-killing is a potential strategy for only some, or all, maternally inherited bacteria. Together, phenotypic and molecular characterisation of male-killers will allow a deeper insight into the interactions between host and endosymbiont, which ultimately may lead to an understanding of how male-killers identify and kill male-hosts.</p> <p>Results</p> <p>A male-killer was detected in the Japanese coccinellid, <it>Propylea japonica </it>(Thunberg) a species not previously known to harbour male-killers. Families produced by female <it>P. japonica </it>showed significantly female-biased sex ratios. One female produced only daughters. This male-killer trait was maternally inherited and antibiotic treatment produced a full, heritable cure. Molecular analysis identified <it>Rickettsia </it>to be associated with the trait in this species of ladybird.</p> <p>Conclusion</p> <p>We conclude that <it>P. japonica </it>is host to a bacterial male-killer that is vertically inherited with variable transmission efficiency. <it>Rickettsia </it>presence correlates with the male-killing trait, but there is some variation in the phenotypic expression of the trait due to interaction with host factors. Phylogenetic analysis using the 16S rRNA and 17 kDa antigen genes suggests there may have been horizontal transfer of <it>Rickettsial </it>male-killers between different ladybird hosts.</p> |
| first_indexed | 2024-12-14T06:55:29Z |
| format | Article |
| id | doaj.art-58729670f835472e952a81abaff7ba7a |
| institution | Directory Open Access Journal |
| issn | 1471-2148 |
| language | English |
| last_indexed | 2024-12-14T06:55:29Z |
| publishDate | 2010-02-01 |
| publisher | BMC |
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| series | BMC Evolutionary Biology |
| spelling | doaj.art-58729670f835472e952a81abaff7ba7a2022-12-21T23:12:40ZengBMCBMC Evolutionary Biology1471-21482010-02-011013710.1186/1471-2148-10-37Discovery and identification of a male-killing agent in the Japanese ladybird <it>Propylea japonica </it>(Coleoptera: Coccinellidae)Majerus Michael ENMajerus Tamsin MO<p>Abstract</p> <p>Background</p> <p>Endosymbionts that manipulate the reproduction of their hosts have been reported widely in invertebrates. One such group of endosymbionts is the male-killers. To date all male-killers reported are bacterial in nature, but comprise a diverse group. Ladybirds have been described as a model system for the study of male-killing, which has been reported in multiple species from widespread geographic locations. Whilst criteria of low egg hatch-rate and female-biased progenic sex ratio have been used to identify female hosts of male-killers, variation in vertical transmission efficiency and host genetic factors may result in variation in these phenotypic indicators of male-killer presence. Molecular identification of bacteria and screening for bacterial presence provide us with a more accurate method than breeding data alone to link the presence of the bacteria to the male-killing phenotype. In addition, by identifying the bacteria responsible we may find evidence for horizontal transfer between endosymbiont hosts and can gain insight into the evolutionary origins of male-killing. Phylogenetic placement of male-killing bacteria will allow us to address the question of whether male-killing is a potential strategy for only some, or all, maternally inherited bacteria. Together, phenotypic and molecular characterisation of male-killers will allow a deeper insight into the interactions between host and endosymbiont, which ultimately may lead to an understanding of how male-killers identify and kill male-hosts.</p> <p>Results</p> <p>A male-killer was detected in the Japanese coccinellid, <it>Propylea japonica </it>(Thunberg) a species not previously known to harbour male-killers. Families produced by female <it>P. japonica </it>showed significantly female-biased sex ratios. One female produced only daughters. This male-killer trait was maternally inherited and antibiotic treatment produced a full, heritable cure. Molecular analysis identified <it>Rickettsia </it>to be associated with the trait in this species of ladybird.</p> <p>Conclusion</p> <p>We conclude that <it>P. japonica </it>is host to a bacterial male-killer that is vertically inherited with variable transmission efficiency. <it>Rickettsia </it>presence correlates with the male-killing trait, but there is some variation in the phenotypic expression of the trait due to interaction with host factors. Phylogenetic analysis using the 16S rRNA and 17 kDa antigen genes suggests there may have been horizontal transfer of <it>Rickettsial </it>male-killers between different ladybird hosts.</p>http://www.biomedcentral.com/1471-2148/10/37 |
| spellingShingle | Majerus Michael EN Majerus Tamsin MO Discovery and identification of a male-killing agent in the Japanese ladybird <it>Propylea japonica </it>(Coleoptera: Coccinellidae) BMC Evolutionary Biology |
| title | Discovery and identification of a male-killing agent in the Japanese ladybird <it>Propylea japonica </it>(Coleoptera: Coccinellidae) |
| title_full | Discovery and identification of a male-killing agent in the Japanese ladybird <it>Propylea japonica </it>(Coleoptera: Coccinellidae) |
| title_fullStr | Discovery and identification of a male-killing agent in the Japanese ladybird <it>Propylea japonica </it>(Coleoptera: Coccinellidae) |
| title_full_unstemmed | Discovery and identification of a male-killing agent in the Japanese ladybird <it>Propylea japonica </it>(Coleoptera: Coccinellidae) |
| title_short | Discovery and identification of a male-killing agent in the Japanese ladybird <it>Propylea japonica </it>(Coleoptera: Coccinellidae) |
| title_sort | discovery and identification of a male killing agent in the japanese ladybird it propylea japonica it coleoptera coccinellidae |
| url | http://www.biomedcentral.com/1471-2148/10/37 |
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