Parthenogenesis in the Argasid Tick Ornithodoros moubata (Murray, 1877)

Abstract

Agamic reproduction in ticks was first reported by Aragio (1912) in a species of Amblyomma which he named agamum but which later was placed in synonymy with A. rotundatum C. L. Koch, 1844. He observed thousands of females which laid fertile eggs in the absence of males. The male of this species is still unknown. Nuttall (1913) observed the same phenomenon in Rhipicephalus bursa. Unmated females remained longer on the host than mated females, they did not become completely engorged, and the number of eggs produced was much smaller than in mated females. None of the larvae were reared to the adult stage. However, in later experiments with R. bursa, Nuttall (1915) considered that parthenogenesis was artificially induced by manipulation accompanying the enumeration of the eggs immersed in normal salt solution and rubbed gently with a camel's-hair brush. Bodkin (1918) reported parthenogenesis in Amblyomma dissimile. Sixty-five ticks of the first generation reared to adults were all females. Parthenogenesis was subsequently observed to the fourth generation. Brumpt (1934), Schulze (1937), and Floch and Abonnenc (1940) have expressed doubt as to the identity of the tick with which Bodkin worked. If the species of tick was A. rotundatum instead of A. dissimile, as has been suggested, the results are in complete agreement with the original report of Aragio for this The fact that the 65 ticks reared to adults in the first generation were exclusively females gives credence to their parthenogenetic origin. Only one reference has been found to parthenogenesis in argasid ticks. Cunliffe (1921) reported that one of ten 0. moubata females held for observation deposited 183 fertile eggs. However, he concluded that this female was probably fertilized unobserved and suggested that further evidence is necessary before parthenogenesis can be considered to be even of rare occurrence in this species. During a study of the quantitative transovarial transmission of Borrelia duttonii in Ornithodoros moubata, 600 ticks were reared from the first nymphal stage to adults by feeding individually at each nymphal stage and as adults on white mice. During the interfeeding periods, the ticks were stored individually in serially-num