SURVIVAL AND DEVELOPMENT OF THE DIFFERENT LIFE STAGES OF IXODES-SCAPULARIS (ACARI, IXODIDAE) HELD WITHIN 4 HABITATS ON LONG-POINT, ONTARIO,CANADA

From November 1989 to April 1993, blood-fed females and unfed adults a nd nymphs of bodes scapularis Say were maintained in housings within 4 different habitats on Long Point, Ontario, Canada, to evaluate the ef fects of habitat on tick development, More fed females survived the wi nter within the maple forest (75.6%) than the cottonwood dune (36.1%), whereas 52.8-62.0% survived the winter within the 2 remaining habitat s. The proportions of females that laid eggs within the maple forest ( 90.3%), oak savannah (83.9%), and white pine habitats (78.4%) were sim ilar and greater than in the cottonwood dune (53.8%). In each habitat and all years, females began laying eggs during late April or eat-iv M ay. The time of egg deposition was consistent whether females fed in N ovember and overwintered, or fed during April of the subsequent year. Significantly more eggs hatched within the maple forest (96.4%) and wh ite pine (79.3%) than in the oak savannah (3.8%) or cottonwood dune ha bitats (0.0%). Hatch occurred in mid-to late July each year. The propo rtion of unfed I. scapularis adults that survived the winter was not s ignificantly different among the 4 habitats. Unfed adults held in the oak savannah and cottonwood dune habitats died by early June, whereas ticks survived until late June or early July within the maple forest a nd white pine habitats. Unfed nymphs survived an average of 3.4 mo (ra nge, 0.5-5.5) longer than unfed adults. Fed larvae placed in the field from 22 April to 3 July 1992 molted or died that year. In contrast, 6 6.7 and 100% of fed larvae placed in the field between 15 and 28 July, and after 28 July, respectively, overwintered before molting. More la rvae successfully molted before overwintering (46.9%) than did those t hat overwintered (17.9%). The proportion of larvae that successfully m olted was greatest within the maple forest and least within the cotton wood dune. Fed nymphs placed in the field from 22 April to 4 June molt ed or died in 1992, whereas 53.6 and 99.2% of fed nymphs placed in the field between 17 June and 28 July, and later than 28 July, respective ly, overwintered before molting. Over all habitats, the proportion of nymphs that molted successfully was similar for those that overwintere d (43.5%) and those that did not (36.0%). The proportion of nymphs tha t molted successfully was greatest in the maple forest (60.6%) and lea st within the cottonwood dune (13.3%). Differences in seasonal extreme s of vapor pressure deficits among habitat types were likely responsib le for habitat-specific differences in survival of I. scapularis. Base d on observations on captive I. scapularis, the life cycle of this tic k on Long Point is completed in 3 or 4 yr.