Sumi Takuto, Miura Kazuki, Miyatake Takahisa
Laboratory of Evolutionary Ecology, Graduate School of Environmental and Life Science, Okayama University, Kita-ku, Okayama, Japan.
National Agriculture and Food Research Organization Western Region Agricultural Research Center, Fukuyama, Japan.
PLoS One. 2017 Apr 12;12(4):e0175373. doi: 10.1371/journal.pone.0175373. eCollection 2017.
Previous studies showed that the survival rate of Wolbachia decreases under high temperature in incubators. It is also known that a high density of Wolbachia in the host body reduces the host emergence rate, while low densities fail to change reproduction rates. However, few studies have examined the density of Wolbachia in hosts in the field. Here, we focus on Wolbachia infection of the pale grass blue butterfly, Zizeeria maha (Lepidoptera: Lycaenidae), which is distributed throughout the Japanese islands. We examined the rate and density of Wolbachia infection in the bodies of butterflies at thirteen locations in Japan. At seven of these places, we collected butterflies in different seasons to determine seasonal differences in the infection rate and density and found that Wolbachia density has seasonal differences within the same population. Moreover, to determine whether Wolbachia density has a geographical cline, we compared the infection density of Wolbachia amongst all geographical populations. In addition, we determined the sequences of Wolbachia wsp and host mtDNA CO1 haplotypes of all populations. The results showed that Wolbachia density increased in early summer and decreased in autumn. Further, the density of Wolbachia infecting the same strain of Z. maha varied amongst populations, although no tendency in geographical cline was observed.
先前的研究表明，在培养箱的高温条件下，沃尔巴克氏体的存活率会降低。众所周知，宿主体内高密度的沃尔巴克氏体会降低宿主的羽化率，而低密度则不会改变繁殖率。然而，很少有研究调查野外宿主中沃尔巴克氏体的密度。在这里，我们关注分布于日本列岛的淡青雀斑小灰蝶（鳞翅目：灰蝶科）的沃尔巴克氏体感染情况。我们调查了日本13个地点蝴蝶体内沃尔巴克氏体的感染率和密度。在其中7个地点，我们在不同季节采集蝴蝶，以确定感染率和密度的季节差异，发现同一群体内沃尔巴克氏体密度存在季节差异。此外，为了确定沃尔巴克氏体密度是否存在地理渐变群，我们比较了所有地理种群中沃尔巴克氏体的感染密度。另外，我们确定了所有种群的沃尔巴克氏体wsp序列和宿主线粒体DNA CO1单倍型。结果表明，沃尔巴克氏体密度在初夏增加，在秋季降低。此外，感染同一品系淡青雀斑小灰蝶的沃尔巴克氏体密度在不同种群间存在差异，尽管未观察到地理渐变群的趋势。
