Redescription of the larva, and description of the nymphal and adult stages of Ornithodoros peruvianus Kohls, Clifford & Jones, 1969 (Acari: Argasidae)

摘要

The soft tick Ornithodoros peruvianus Kohls, Clifford & Jones, 1969 was described as a parasite of bats in Peru upon the examination of engorged larvae only. Recently, larvae of this tick species were reported on bats from northern Chile. However, the adult and nymphal stages of O. peruvianus have remained undescribed. This study aimed to redescribe the larva of O. peruvianus based on unfed specimens, and to describe nymphs, the male and the female of this species. Ticks were collected on the walls inside three caves in northern Chile. Two females laid eggs in the laboratory. Part of the unfed larvae was separated for morphological and morphometrical analyses, and the remaining specimens were fed upon laboratory mice in order to obtain subsequent nymphal and adult stages. The first nymphal stage (N1) moulted either to male or to a second nymphal stage (N2) without feeding. Obtained N2 moulted either to male or female after one meal. PCR amplification of tick mitochondrial 16S rRNA of specimens from the three caves revealed almost identical sequences. The unfed larva of O. peruvianus has an elongated idiosoma, and fringed setae cover the ventral surfaces of coxae, palps and tarsi. Nymph 1 has a thin integument covered by incipient mammillae and barely noticeable dorsal disks; it lacks cheeks and possesses few short setae on the basis capitulum. Nymph 2 has a pair of small cheeks and resembles adult stages in its tegumentary traits and capitulum. Adult stages exhibit developed cheeks (larger in females) without the capacity to completely cover the capitulum. Very small and low mammillae cover the surface of the dorsal idiosoma in adults. As this feature also occurs in other bat-associated soft ticks, regardless of their phylogenetic relatedness, small mammillae in bat soft ticks are suggestive of convergent evolution.