Effect of mating on oogenesis and oviposition in the tick Argas persicus (Oken)

Abstract

The initial pattern of oogenesis after a feed is similar for mated and unmated A. persicus. The peak number of mature oocytes within the females occurred on the seventh day at 30 °C. Both groups ovulated but only mated females oviposited. At the end of the first week the mature eggs of unmated females began to undergo dissociation and resorption. The early onset of this process seems to exclude the presence of unlaid eggs as a factor inhibiting ovarian maturation. Many more eggs matured within the mated than the unmated female. After oviposition, the ovaries appear as in the unfed virgin except oocytes are fewer. When the male was mated consecutively to the 7–8th virgin female, there was a decrease in the number of eggs laid. This indicates that the male factor(s) effecting oogenesis and oviposition act on a quantitative rather than an ‘all or none’ basis. To determine whether a female was effectively mated, the ampulla must be checked for sperm. The reason for this is that the spermiophore capsules may be resorbed or may lack sperm. Spermless spermiophores enhanced fecundity but did not effect oviposition. There was evidence of mechanical influence on oocyte maturation when beads were introduced into the vagina of A. persicus. An increase in the number of beads increased the number of mature oocytes. Chemical influence on oogenesis was demonstrated by injection of male gland complex into the body cavity of unmated females.