Resumen de Genetic variation of phtheiropoios wetmorei (Phthiraptera: Gyropidae), an ectoparasite of ctenomys minutus (Rodentia: Ctenomyidae) in Brazil
Patrícia Quintana Langone, Gertrud Müller, Thales Renato Ochotorena de Freitas
Phtheiropoios wetmorei is a chewing louse that parasitizes at least fifteen species of subterranean rodents of the genus Ctenomys (tuco-tucos). In Brazil, it can be found on two ctenomyids: Ctenomys torquatus and Ctenomys minutus. Most studies on P. wetmorei have focused on new records of hosts and to date no genetic study has been carried out on this louse. In order to evaluate the genetic diversity of P. wetmorei, we sampled twelve populations of C. minutus across its entire distribution range in Brazil. One hundred tuco-tucos were collected, all of them infested with P. wetmorei. One louse from each individual rodent was used in an extraction buffer with CTAB and proteinase-k. The PCR was carried out with the primers LCO 1490 and HCO 2198. A 624bp fragment of the mitochondrial gene cytochrome oxidase c subunit I (COI) was obtained. The softwares MEGA 5.03 and Arlequim 3.11 were used to estimate molecular diversity. A total of thirty three haplotypes was found, none of which were shared among populations. A high overall haplotype diversity (H=0.9519) was detected. The number of variable sites was also high (n=128). Pairwise differences between populations ranged from 0.3958 to 0.9969. Results show a high variation between lice from different localities, suggesting a reproductive isolation. Such pattern was already expected since the hosts are known to have a patchy distribution with little contact among populations. Furthermore, lice have low vagility and host switching are unlikely to occur. This is the first comprehensive study about genetic variation of lice parasitizing Ctenomys. Future studies are needed to provide better understanding of the relationships between genetic structure of hosts and lice in this system.
