DISPERSAL OF BLACKLEGGED TICK (ACARI, IXODIDAE) NYMPHS AND ADULTS AT THE WOODS-PASTURE INTERFACE

Marked nymphal and adult blacklegged licks, Ixodes scapularis Say, wer e released in 4 host-exclusion cages and 4 similar control areas, all straddling the woods-pasture interface. Both nymphs and adults were re captured by flagging at regular intervals outside the cages, having th erefore actively dispersed >4.5 m (i.e., without involvement of verteb rates). Nymphs were recaptured much more often (>90%) in the woods tha n pastures, whereas were 62.8% of recaptured adults were taken in past ures. Females were recaptured in equal numbers in pastures and woods, but 75.4% of recaptured males were in pastures. Adults that dispersed into pastures were recaptured an average of 1.6 and 3.7 m from the woo ds edge in 1992 and 1993, respectively, and as far as 7-8 m from the w oods edge. Nymphs dispersed shorter distances than adults with 66% of the recaptured nymphs found 2-3 m from their release points, and >46% of recaptured adults found >5 m from their release points. Twice as ma ny nymphs were recaptured from the caged than uncaged sites. The lower numbers of nymphs recaptured from control sites compared with caged s ites are probably the result of host acquisition; the absence of this discrepancy with the adults may reflect by their ability to move relat ively quickly from the host-exclusion cages and became available for h ost contact.