Palp-splaying behavior and a specific mouthpart site associated with active water vapor uptake in Amblyomma americanum (Acari : Ixodidae)

Ticks actively absorb water vapor from unsaturated air via their mouthparts . A wax technique was used to cover select areas of the mouthparts of the l one star tick, Amblyomma americanum (L.), to examine whether a specific sit e is involved in uptake. Covering dorsal, ventral, and distal regions faile d to inhibit uptake, whereas wax applied to the proximal region, specifical ly the hypostome-cheliceral junction, blocked water absorption. A novel occ urrence of a palp-splaying behavior was observed during hydrating condition s (93% RH), while ticks were motionless, compared with those held at desicc ating conditions (63% RH), which were more active and the palps were not sp layed.