Test of the invasive pathogen hypothesis of bumble bee decline in North America
Test of the invasive pathogen hypothesis of bumble bee decline in North America
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DOI：
10.1073/pnas.1525266113
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发表时间：
2016-04-19
影响因子：
11.1
通讯作者：
Thorp, Robbin
中科院分区：
文献类型：
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作者：
Cameron, Sydney A.;Lim, Haw Chuan;Thorp, Robbin
真菌病害是全球生物多样性下降的关键因素。最近发现真菌病原体Nosema bombi在北美熊蜂（Bombus）的衰落物种中广泛存在，间接证据表明从欧洲引进的外来物种。由于缺乏对全球遗传变异、地理起源和N.在北美人口减少的情况下。因此，N. bombi及其在大黄蜂数量减少中的潜在作用仍是推测性的。我们分析了从1980年到2011年美国和欧洲的微孢子虫流行率和遗传变异，在20世纪90年代初所谓的引入之前，从这段时间的熊蜂自然历史收集标本中提取微孢子虫DNA。家蚕微孢子虫的流行率从20世纪80年代的低检出率显著增加到20世纪90年代中后期的高检出率，这与报告的大规模感染性暴发的时期相对应。在北美的商业熊蜂饲养种群中。尽管频率增加，我们没有发现外来N的确凿证据。根据对全球微孢子虫种群的遗传分析，Bombi起源;目前在下降的美国熊蜂中发现的广泛的微孢子虫菌株在商业殖民贸易之前就存在于美国。值得注意的是，美国N. bombi与西欧主要发现的蜜蜂没有明显不同，这两个地区的特点是遗传多样性低，而亚洲的多样性高，商业蜜蜂育种活动低或不存在。
Emergent fungal diseases are critical factors in global biodiversity declines. The fungal pathogen Nosema bombi was recently found to be widespread in declining species of North American bumble bees (Bombus), with circumstantial evidence suggesting an exotic introduction from Europe. This interpretation has been hampered by a lack of knowledge of global genetic variation, geographic origin, and changing prevalence patterns of N. bombi in declining North American populations. Thus, the temporal and spatial emergence of N. bombi and its potential role in bumble bee decline remain speculative. We analyze Nosema prevalence and genetic variation in the United States and Europe from 1980, before an alleged introduction in the early 1990s, to 2011, extracting Nosema DNA from Bombus natural history collection specimens from across this time period. Nosema bombi prevalence increased significantly from low detectable frequency in the 1980s to significantly higher frequency in the mid-to late-1990s, corresponding to a period of reported massive infectious outbreak of N. bombi in commercial bumble bee rearing stocks in North America. Despite the increased frequency, we find no conclusive evidence of an exotic N. bombi origin based on genetic analysis of global Nosema populations; the widespread Nosema strain found currently in declining United States bumble bees was present in the United States before commercial colony trade. Notably, the US N. bombi is not detectably different from that found predominantly throughout Western Europe, with both regions characterized by low genetic diversity compared with high levels of diversity found in Asia, where commercial bee breeding activities are low or nonexistent.