Abnormal Development of Amblyomma variegatum (Acarina: Ixodidae)

Of 5,000 engorged Amblyomma variegatum larvae, 16 were observed with abnormal external features, centering on partial twinning of the posterior region of the body, with the presence of two anal pores and two genital grooves. According to the number of legs and spiracular plates, nymphs and adults were grouped into three types. Although there was only one midgut, it divided into a pair of hindguts, each of which opened into a separate rectal sac. In both sexes of adults, double reproductive organs were associated with two genital pores. All of the developmental stages fed well on rabbits. However, only one female oviposited and the eggs did not hatch.