Study of the Weight of Eggs from Six Ixodid Species from Brazil

The generally large acarines included in the superfamily Ixodoidea apparently evolved as obligate parasites of Reptilia in the late Paleozoic or early Mezozoic era. During subsequent coevolution with birds and mammals, adaptations of most tick species have been conservative. Structural, developmental, physiological, ethological, and reproductive properties and processes have changed, but chiefly within narrow parameters (Hoogstraal & Kim 1985). In Brazil, there are 54 known tick species (Aragão & Fonseca 1961). Among the Ixodidae, the genus Ixodes (Prostriata, Ixodinae) is represented by 9 species. In the Metastriate line, Amblyomma (subfamily Amblyomminae) is the largest genus constituted by 33 species. The Haemaphysalinae (genus Haemaphysalis) is represented by only 3 species. The remaining species belong to the Rhipicephalinae. Boophilus microplus was introduced in Brazil with cattle by Portuguese in the XVI century. Rhipicephalus sanguineus has spread out among the world parasitizing dogs, Canis familiaris, which are not the host they coevolved with. Another species, Dermacentor nitens, possibly penetrated in South America during Pliocene with the massive invasion of North America mammals across the newly formed isthmus of Panama (Balashov 1994). Among the Argasidae, the genus Argas (Argasinae) is represented by A. miniatus, endemic in Latin America. The genus Ornithodoros (Ornithodorinae) contains 6 species parasitizing mainly bats, although they often feed on humans and other