New survival record of southern cattle tick in subfreezing temperatures.

摘要

The southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini), is considered to be one of the most significant pests of cattle worldwide. A vector for piroplasmosis, or cattle fever, the southern cattle tick is a key target of an aggressive eradication program along the U.S.-Mexico border. Endemic to subtropical and tropical regions, southern cattle ticks are limited in range by climate and temperature. Neither adults nor larvae of southern cattle tick survive more than a few days of subfreezing temperatures. Nonetheless, in a separate study of fecundity of southern cattle tick in different field conditions, where bagged samples of egg masses were allowed to hatch in the field then placed in a freezer in order to estimate egg hatch, a single southern cattle tick larva was found alive following exposure to room temperature after 20 days of cold-exposure. Although quite anomalous, this report of this outlying observation suggests the possibility that southern cattle tick can survive extremely cold temperatures for long durations.