Data from: Tetracycline-exposed Drosophila melanogaster males produce fewer offspring but a relative excess of sons

A large diversity of species possesses endosymbionts; these endosymbionts can exhibit mutualistic, parasitic, and commensal relationships with their hosts. Previous work has consistently revealed that depleting endosymbiont titer with antibiotic treatment can significantly alter host fitness and function, particularly with respect to reproductive phenotypes. Although these findings are often interpreted as resulting from the breakdown of highly coevolved symbioses, it is possible that antibiotic treatment itself rather than endosymbiont removal contributes to the observed perturbations in reproductive phenotypes. Here, we investigate the effect of tetracycline treatment on sex ratio and male reproductive fitness using Drosophila melanogaster as a model system. Our results indicate that tetracycline-treated males produce a relative excess of sons. We also find that tetracycline treatment reduces the number of progeny produced by treated males but not treated females. These findings are independent of the effects of tetracycline on Wolbachia titer and implicate the antibiotic itself as mediating these changes. It is yet unclear whether the sex ratio shift and reduction in male reproductive fitness are direct or indirect consequences of tetracycline exposure, and more work is needed to determine the molecular mechanisms by which these disturbances in reproductive phenotypes arise. Our data highlight the importance of considering the potentially confounding effects of antibiotic treatment when investigating the effects of endosymbiont depletion on host phenotypes.

大量物种均携带内共生体（endosymbiont）；此类内共生体可与宿主形成互利共生、寄生或偏利共生关系。既往研究一致表明，通过抗生素处理降低内共生体滴度，可显著改变宿主的适合度与生理功能，尤其是在生殖表型方面。尽管此类发现常被解读为高度协同进化的共生关系被破坏所致，但也存在另一种可能：是抗生素处理本身，而非内共生体的清除，导致了观察到的生殖表型扰动。本研究以黑腹果蝇（Drosophila melanogaster）为模式生物，探究四环素（tetracycline）处理对性别比例与雄性生殖适合度的影响。结果显示，经四环素处理的雄性果蝇产生的雄性子代比例相对偏高。同时研究发现，四环素处理会降低处理组雄性的子代产量，但对处理组雌性无此影响。上述发现与四环素对沃尔巴克氏体（Wolbachia）滴度的作用无关，表明抗生素本身介导了这些表型变化。目前尚不清楚性别比例偏移与雄性生殖适合度下降是四环素暴露的直接还是间接后果，仍需更多研究阐明此类生殖表型扰动产生的分子机制。本研究数据强调，在探究内共生体清除对宿主表型的影响时，需考虑抗生素处理本身可能带来的混淆效应。