Interaction of Gulf Coast tick, Amblyomma maculatum Koch, nymphs on cattle

Concern over the vector potential of the Gulf Coast tick, Amblyomma maculatum\nKoch, with the pathogen Ehrlichia ruminantium Dumler, causative agent of the disease\nheartwater, has increased the need for fundamental knowledge of tick ecology and\nbehavior, specifically immature tick biology. Texas strain A. maculatum adult male ticks,\nknown to emit attraction-aggregation-attachment pheromone (AAAP), were used to\nartificially simulate immature tick interaction with adults, in forced environments, on\ncattle. Artificial areas were grouped by treatment level, which were 1) aggregating,\nattached adult males, 2) aggregating attached adult females or 3) an empty area with no\nadults, as a control. Immature ticks were noted to be 6 times more likely to be\naggregating in the AAAP treatment area when adult males were present. In the presences\nof either adult female ticks or no ticks at all, immature ticks were found to be attaching at\nrandom within the given area were they where permitted to feed. A second correlation of\nmortality was noted among immature ticks in the presence of AAAP emitting adult male\nticks. In the permitted area where immature ticks could attach and feed, immature ticks\nwere twice as likely to have survived to engorgement if adult male ticks were present in\nthe area as well (53%). There was no difference in the survival rate among immature\nticks if adult females were present or no adults at all, 26% and 21%, respectively. The study demonstrated that a significant attraction existed between immature ticks and\nattached adult males emitting AAAP.