Life Cycle of <I>Ixodes (Ixodes) loricatus</I> (Acari: Ixodidae) Under Laboratory Conditions

Abstract

The life cycle of Ixodes (Ixodes) loricatus Neumann, reared in the laboratory, is described. Engorged females collected from opossums trapped in the states of Minas Gerais and São Paulo, Brazil, which were used to start the laboratory colonies, were designated as BMG and CSP, respectively. Larval and nymphal ticks from both colonies fed separately on Rattus norvergicus Berkenhout or Calomys callosus Rengger, whereas Didelphis marsupialis L and Didelphis albiventris Lund were used as hosts for BMG and CSP adults, respectively. Biological and developmental data obtained from ticks of both the BMG and CSP colonies that were reared separately for two consecutive generations were compared. The percentage of fed or molted ticks reared on C. callosus was higher than that recorded for ticks fed on R. norvergicus in the majority of the observations. Despite significant differences among several of the biological parameters, the pattern of the life cycles of the two tick colonies was similar. Results indicated that the mean life cycle duration of I. (I.) loricatus was approximately 7 mo from parental oviposition to the occurrence of F1 eggs, regardless of geographic origin or host species.

Life cycle of Ixodes luciae (Acari: Ixodidae) in the laboratory

“…These values were very similar to previously reported data for I. loricatus under laboratory conditions, for which the life cycle was completed in 98 to 102 days (without prefeeding periods), considering feeding of immature ticks on C. callosus or R. norvegicus, adults on Didelphis spp, and off-host development at 27°C (Schumaker et al 2000). Grouping the five generations, sex ratio of adult ticks was 1:1.3 (males/females).…”

“…On this later host species, nearly 10% of the larvae took ≥20 days to complete feeding during five consecutive generations. Interestingly, longer feeding periods (up to 19 days) were previously observed for I. loricatus larvae exposed to C. callosus than those exposed to R. norvegicus (up to 9 days) (Schumaker et al 2000). The mechanism and biological significance of such an unusual prolonged larval feeding period remain unknown.…”

“…Among the eight Ixodes species occurring in Brazil, life cycle studies have been reported only for I. loricatus (Schumaker et al 2000) and partially for I. schulzei (Labruna et al 2003) and I. amarali (Faccini et al 1999). Here, we evaluated the life cycle of I. luciae in the laboratory.…”

Taxonomic Status ofIxodes didelphidis(Acari: Ixodidae)

“…Life-cycle data of the BMG and CSP colonies obtained during laboratory rearing were published by Schumaker et al (2000) and were used for comparison with the TRJ colony data. Biological data relative to the life-cycle of the PSP colony was not recorded.…”

“…Throughout this study, ticks were reared at 27ЊC and 95Ð98% RH in an incubation oven maintained under total darkness, except when ticks were feeding on the host. All infestation procedures were performed as described by Schumaker et al (2000) for the BMG and CSP colony-life-cycle study.…”