Boyd Bret M, House Niyomi, Toloza Ariel C, Reed David L
Center for Biological Data Science, Life Sciences, Virginia Commonwealth University, 1000 West Carry Street, Richmond, Virginia 23284.
Department of Biological Sciences, Virginia Tech, 926 West Campus Drive, Blacksburg, Virginia 24061.
J Parasitol. 2025 Jul 1;111(4):412-418. doi: 10.1645/24-148.
The sucking lice (Anoplura: Psocodea: Insecta) parasitize mammals, exclusively consuming blood, which does not contain sufficient quantities of B vitamins to support louse development. Lice are dependent on maternally inherited endosymbiotic bacteria, which can synthesize B vitamins and make them available to the louse. Although most louse species parasitize 1 mammal species, lice occasionally colonize a different mammal species. Despite endosymbiotic bacteria being essential for louse development, little is known about the impact, if any, of a louse colonizing a new mammal species on the louse's endosymbiotic bacteria. To address this knowledge gap, we sought to examine genomic diversity in maternally inherited and host-beneficial endosymbiotic bacteria in sucking lice following the likely colonization of a new host. Here, we examined the genomes of endosymbiotic bacteria, Candidatus Riesia pediculicola, from the human head louse, Pediculus humanus. Pediculus humanus (and their endosymbiotic bacteria) are found on humans and South American primate species. The association of P. humanus with humans predates the appearance of modern humans; however, P. humanus appears to have colonized South American primates more recently (likely following the arrival of humans in South America). We examined the genome of Candidatus Riesia from P. humanus isolated from humans (Homo sapiens) and South American black howler monkeys (Alouatta caraya). Here, we find that endosymbiont diversity in lice collected from black howler monkeys included one-half of all known haplogroups described from lice collected from humans. Furthermore, the endosymbiont haplotypes identified from lice on the black howler monkeys reflect the haplotype diversity of endosymbionts present in lice parasitizing humans in the same geographic region. It is not known if the genetic diversity in the endosymbionts of P. humanus parasitizing the black howler monkey is the result of the ongoing movement of lice from humans to black howler monkeys or from a single host switch involving a genetically diverse population of endosymbionts.
吸虱（虱目：啮虫总目：昆虫纲）寄生于哺乳动物，仅以血液为食，而血液中含有的B族维生素量不足以支持虱子的发育。虱子依赖母系遗传的内共生细菌，这些细菌能够合成B族维生素并供虱子利用。尽管大多数虱类寄生于一种哺乳动物，但虱子偶尔也会寄生于不同的哺乳动物物种。尽管内共生细菌对虱子的发育至关重要，但对于虱子寄生于新的哺乳动物物种对其体内共生细菌的影响（如果有影响的话）却知之甚少。为了填补这一知识空白，我们试图研究吸虱在可能寄生于新宿主后，其母系遗传且对宿主有益的内共生细菌的基因组多样性。在此，我们研究了来自人头虱（人虱）的内共生细菌——嗜人瑞氏菌（Candidatus Riesia pediculicola）的基因组。人虱（及其内共生细菌）存在于人类和南美洲灵长类动物物种身上。人虱与人类的关联早于现代人类的出现；然而，人虱似乎是在更近的时期寄生于南美洲灵长类动物（可能是在人类抵达南美洲之后）。我们研究了从人类（智人）和南美洲黑吼猴（Alouatta caraya）身上分离出的人虱的嗜人瑞氏菌基因组。在此，我们发现从黑吼猴身上采集的虱子的内共生体多样性包括从人类身上采集的虱子中描述的所有已知单倍群的一半。此外，从黑吼猴身上的虱子中鉴定出的内共生单倍型反映了在同一地理区域寄生于人类的虱子中存在的内共生体的单倍型多样性。尚不清楚寄生于黑吼猴的人虱内共生体中的遗传多样性是虱子从人类持续转移到黑吼猴的结果，还是涉及一群基因多样的内共生体的单次宿主转换的结果。
