New survival record of southern cattle tick in subfreezing temperatures

Authors: Racelis, Alexis; Davey, Ronald

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2011
Publication Date: 9/10/2011
Citation: Racelis, A.E., Davey, R.B. 2011. New survival record of southern cattle tick in subfreezing temperatures. Southwestern Entomologist. 36(3):383-385.

Interpretive Summary: The southern cattle tick is considered to be one of the most significant pests of cattle worldwide. A vector for piroplasmosis, or cattle fever, R. microplus is a key target of an aggressive eradication program along the US Mexico border. Climate and temperature are limiting factors for the southern cattle tick, which is restricted to subtropical and tropical regions. Neither adults nor larvae of R. microplus have been shown to survive more than a few days of sub-freezing temperatures. However, in a separate study of the reproduction and survivorship of southern cattle tick in different field conditions, several sealed bagged samples of newly hatched larvae were placed in a sub-zero freezer to kill live larvae so to estimate hatch. We found one single larva after 20 days of exposure to subfreezing temperatures. The possibility that R. microplus can survive extremely low temperatures for long durations warrants an in depth investigation of the biological significance of a lower temperature threshold in the context of management implications of this important cattle pest.

Technical Abstract: The southern cattle tick, Rhicephalus (Boophilus) microplus (Canestrini) is considered to be one of the most significant pests of cattle worldwide. A vector for piroplasmosis, or cattle fever, R. microplus is a key target of an aggressive eradication program along the U.S./Mexico border. Endemic to subtropical and tropical regions, R. microplus is limited in its range by climate and temperature. Neither adults nor larvae of R. microplus survive more than a few days of sub-freezing temperatures. Nonetheless, in a separate study of fecundity of R. microplus in different field conditions, where bagged samples of egg masses were allowed to hatch in the field, then placed in a minus 80° C freezer in order to estimate egg hatch, a single R. microplus larva was found alive following exposure to room temperature after 20 d of cold-exposure. Although quite anomalous, this report of this outlying observation is evidence of the possibility that R. microplus can survive extremely low temperatures for long durations.