Reproductive parasites such as Wolbachia are extremely widespread amongst the arthropods and can have a large influence over the reproduction and fitness of their hosts. Undetected infections could thus confound the r...Reproductive parasites such as Wolbachia are extremely widespread amongst the arthropods and can have a large influence over the reproduction and fitness of their hosts. Undetected infections could thus confound the results of a wide range of studies that focus on aspects of host behavior, reproduction, fitness, and degrees of reproductive isolation. This potential problem has already been underlined by work investigating the in- cidence of Wolbachia infections in stocks of the model system Drosophila melanogaster. Here we survey a range of lab stocks of further commonly used model arthropods, fo- cusing especially on the flour beetles Tribolium castaneum and Tribolium confusum, the cowpea weevil Callosobruchus maculatus and related species （Coleoptera： Tenebrionidae and Bruchidae）. These species are widespread stored product pests so knowledge of infec- tions with symbionts further has potential use in informing biocontrol measures. Beetles were assessed for infection with 3 known microbial reproductive parasites： Wolbachia, Rickettsia, Spiroplasma. Infections with some of these microbes were found in some of the lab stocks studied, although overall infections were relatively rare. The consequences of finding infections in these or other species and the type of previous studies likely to be affected most are discussed.展开更多
Recent studies investigating possible causes of male subfertility have largely focused on how lifestyle or environmental factors impact on the process of spermatogenesis, Markedly, fewer studies have investigated thos...Recent studies investigating possible causes of male subfertility have largely focused on how lifestyle or environmental factors impact on the process of spermatogenesis, Markedly, fewer studies have investigated those risk factors that result in reduced sperm quality, such as poor sperm motility. The speed at which sperm swim is a major predictor of fertility and is extremely variable in human populations. It has been hypothesized that offspring sex may be adaptively manipulated to maximize the offspring＇s reproductive fitness （e.g., parents with genes for good male fertility traits, such as high sperm speed, would produce primarily sons and fewer daughters because the offspring will inherit advantageous male fertility genes）. Conversely, parents with poor male fertility genes would produce primarily daughters, We tested whether there was an association between how fast a man＇s sperm swam and the sex bias of his siblings in a sample of men attending clinic for fertility investigations with their partner and with a wide range of semen characteristics, including sperm speed. We found that the sex bias of a man＇s siblings is associated with his sperm speed; men with female-biased siblings had significantly slower sperm （judged using computer-assisted sperm analysis （CASA）） than men from male-biased sibships. This observation suggests family composition is an important factor that needs to be considered in future eDidemiological and clinical studies of human fertility,展开更多
文摘Reproductive parasites such as Wolbachia are extremely widespread amongst the arthropods and can have a large influence over the reproduction and fitness of their hosts. Undetected infections could thus confound the results of a wide range of studies that focus on aspects of host behavior, reproduction, fitness, and degrees of reproductive isolation. This potential problem has already been underlined by work investigating the in- cidence of Wolbachia infections in stocks of the model system Drosophila melanogaster. Here we survey a range of lab stocks of further commonly used model arthropods, fo- cusing especially on the flour beetles Tribolium castaneum and Tribolium confusum, the cowpea weevil Callosobruchus maculatus and related species （Coleoptera： Tenebrionidae and Bruchidae）. These species are widespread stored product pests so knowledge of infec- tions with symbionts further has potential use in informing biocontrol measures. Beetles were assessed for infection with 3 known microbial reproductive parasites： Wolbachia, Rickettsia, Spiroplasma. Infections with some of these microbes were found in some of the lab stocks studied, although overall infections were relatively rare. The consequences of finding infections in these or other species and the type of previous studies likely to be affected most are discussed.
文摘Recent studies investigating possible causes of male subfertility have largely focused on how lifestyle or environmental factors impact on the process of spermatogenesis, Markedly, fewer studies have investigated those risk factors that result in reduced sperm quality, such as poor sperm motility. The speed at which sperm swim is a major predictor of fertility and is extremely variable in human populations. It has been hypothesized that offspring sex may be adaptively manipulated to maximize the offspring＇s reproductive fitness （e.g., parents with genes for good male fertility traits, such as high sperm speed, would produce primarily sons and fewer daughters because the offspring will inherit advantageous male fertility genes）. Conversely, parents with poor male fertility genes would produce primarily daughters, We tested whether there was an association between how fast a man＇s sperm swam and the sex bias of his siblings in a sample of men attending clinic for fertility investigations with their partner and with a wide range of semen characteristics, including sperm speed. We found that the sex bias of a man＇s siblings is associated with his sperm speed; men with female-biased siblings had significantly slower sperm （judged using computer-assisted sperm analysis （CASA）） than men from male-biased sibships. This observation suggests family composition is an important factor that needs to be considered in future eDidemiological and clinical studies of human fertility,
