Abstract

Almost nothing is known about the questing and dispersal behavior of immature Gulf Coast ticks (Amblyomma maculatum), a vector of both medical and veterinary concern. This experiment examined host-seeking (questing) and dispersal of marked, previously colonized, nymphal A. maculatum released in field plots in rural Oktibbeha County, Mississippi during 2015. A total of 500 (250 per replication) A. maculatum nymphs were painted and released in 5 plots (50 ticks each time). Observations were then made 5 times, approximately every 3 days, searching the plots for ticks from the release points outwards to 50 cm. Mean overall vertical questing height of ticks in Replication 1 in March (5.13 cm) was significantly higher than that of Replication 2 in April (2.57 cm) for a combined mean questing height of 3.58 cm. Ticks dispersed at a mean rate of 1.71 cm/day (Replication 1) and 0.98 cm/day (Replication 2), for an overall mean dispersal rate of 1.27 cm/day. When observation days where tick movement was impacted by adverse weather conditions were excluded, means between the replications were much closer. Only 38 of 2,500 possible total observations (1.5%) of the marked ticks were subsequently seen questing in this study, perhaps mirroring low questing rates of nymphal A. maculatum in nature. Additionally, 2 ticks were found in dense vegetation at the base of a plant. These data show that nymphs of this species disperse slowly, quest low to the ground, and can hide in very dense vegetation.

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