Isolation of 2,6-dichlorophenol from the cattle tick <i>Boophilus microplus</i>: Receptor cell responses but no evidence for a behavioural response

2,6-Dichlorophenol, a compound known as a sex pheromone for several metastriate tick species, was isolated from different life-stages of the cattle tick <i>Boophilus microplus</i>. Receptor cells in two wall-pore single-walled sensilla on the tarsus I of male ticks responded to this compound in a dose-dependant manner. Using these receptors as specific detectors for compounds in the effluent of a gas chromatograph, we detected 2,6-dichlorophenol in extracts of females, males, engorged nymphs and larvae of this one-host tick, but not in an extract of eggs. No other components of the extracts elicited responses from these olfactory sensilla. However, male B. microplus were not arrested on a glass bead treated with 2,6-dichlorophenol and placed on a membrane in a host-simulating arena, whereas a bead treated with a female extract did evoke a strong arrestment response. In addition, no odour-conditioned anemotaxis, change in angular velocity or speed of males walking on a locomotion compensator was observed in response to this compound in a conditioned air-stream. We could therefore not establish a role for 2,6-dichlorophenol on its own as a semiochemical in males of this species.