Observations on Some Biological Characteristics of Rhipicephalus sanguineus Sensu Lato (Acari: Ixodidae) Under Natural and Laboratory Conditions in Nigeria

The brown dog tick, Rhipicephalus sanguineus sensu lato (s. l.) is a globally distributed tick of medical and veterinary significance. This study reports some observations on the biological characteristic of the brown dog ticks kept under natural and laboratory conditions in Nigeria. Variation in biological parameters was observed within the Nigerian R. sanguineus s. l. population kept under various conditions. A higher number of R. sanguineus exhibited the type 1 oviposition pattern than the type 2 pattern. The type 1 pattern was observed in 84.2 % and 80 % of R. sanguineus s. l. reared under laboratory and natural conditions, respectively. The pre-oviposition period was significantly shorter in ticks maintained under laboratory conditions than under natural conditions. Similarly, ticks kept under laboratory conditions laid significantly more eggs with higher egg mass weight than ticks kept under natural conditions. Furthermore, the incubation period and the total weight loss by female ticks throughout the oviposition period differed significantly between the two groups (P < 0.05). The engorged R. sanguineus s. l. females kept at 4 °C survived for up to 21 days and remained viable producing fertile eggs. Egg of R. sanguineus s. l. kept at 4 °C for up to 63 days retain viability and were able to hatch to larvae after variable incubation periods when returned to ambient temperatures depending on the duration of storage at 4 °C. The results showed that the tropical lineage of the brown dog tick can survive and remain fecund at low temperatures, suggesting that it can be translocated and established in temperate regions.