ATTACHMENT-SITE PATTERNS OF ADULT BLACKLEGGED TICKS (ACARI, IXODIDAE)ON WHITE-TAILED DEER AND HORSES

The attachment site pattern of adult Ixodes scapularis Say on white-ta iled deer and horses in Maryland was determined by whole-body examinat ions during fall and spring periods of tick host-seeking activity. On deer in the fall, both female and male I. scapularis attached largely to anterior dorsal body regions, with attachment to the ears (outside) , head, neck, and brisket accounting for 87.9% of females and 86.6% of males. The attachment pattern of females differed between bucks and d oes during fall, but not in spring, and both females and males were mo re abundant on bucks than does during fall, but not in spring. Neither female nor male attachment patterns on deer differed between fall and spring seasons. In contrast to deer, the ears and neck of horses were largely devoid of blacklegged ticks, and 84% of the females were atta ched either on the chest, in the axillae of the fore and rear legs, or under the jawbone. The restricted attachment of female blacklegged ti cks to ventral body regions of horses may reflect avoidance of light. An understanding of the attachment patterns of adult I. scapularis, an increasingly abundant and economically important species, enhances sa mpling of feeding ticks, deticking to limit host irritation or exposur e to tick-borne pathogens, and identifies body areas that should be ta rgeted for delivery of repellents or acaricides.