Phenotypic anomalies in a collection of neotropical ticks (Ixodidae)

A total of 62(1%) ticks with phenotypic anomalies was found amongst 64,473 Ixodoidea collected from March 1976 to March 1997 in mainland Argentina (Ne otropical). No anomalies were detected in the few individuals of the subfam ilies Haemaphysalinae and Ixodinae collected. Thirty-eight (1.8%) of the 20 ,626 ticks of the subfamily Amblyomminae bad anomalies, as did 24 (0.5%) of the 43,651 ticks of the subfamily Rhipicephalinae (P<0.001, chi(2)). Anoma lies in Amblyomminae were more frequent in females than in males (P<0.001) or nymphs (P<0.01), while no statistical differences were found between the stages of Rhipicephalinae. In agreement with previous authors, gynandromor phism was more frequent in Amblyomminae (3 Amblyomma neumanni gynandromorph s) than in Rhipicephalinae (1 gynander of Boophilus microplus).