Location of larvae of the Winter Tick, Dermacentor albipictus (Pack.), in Elk Island National Park, Alberta

Abstract

1982. Location of larvae of the Winter Tick, Dermacentor albipictus (Pack.) in Elk Island National Park, Alberta. Canadian Field-Naturalist 96(2): 211-213. After reports of heavy infestations of Winter Ticks on moose in Elk Island National Park, Alberta, a search was made for the free-living tick larvae on 15 October 1980. Large aggregations were found on grass, shrubs, and the boundary fence in the northeast corner of the Park. Some larvae had ascended to the top of the fence, a height of about 2.2 m. Infestations of WinterTicks on moose in Elk Island Park sometimes exceed 105 ticks per moose and are associated with hair loss and deaths in late winter (Samuel and Barker 1979). Since most larvae of this species emerge in the summer but do not ascend the grass until September or October at Kamloops, Brit-ish Columbia (Wilkinson 1967), a preliminary reconnaissance was carried out on 15 October 1980 to investigate the distribution and behavior of the free-living larvae in the Park. Larvae were sought by visual examination of grass tips, low shrubs, and other suitable supports, and by sweeping with a 1 X 1 m flannelette flag and a 0.5 X 0.5 m 'propashnik' sampler (Blagoveshchensky 1957). A thin layer of snow on the ground made the larvae more visible but hindered the use of the samplers by dampening the cloth. Most of the larvae were found by visual inspection because they were in large aggregations. Many were found at several locations near and on the border fence (Figures 1 to 4) in the northeast corner of the Park where visitors had reported picking up larvae on their clothing. None were found at a salt lick north of the Park headquarters, or at the 'aspen exhibit' clearing , or on the trail inside the southern boundary fence adjacent to Highway 16. A systematic survey of the Park was not attempted. At one ofthe infested sites, larvae had settled in the 'knots' in the page-wire fence (Figures 1 and 2) at 0.2-1.7 m above ground, good heights to crawl onto a moose's legs or trunk. However, a few aggregations were on the top wire about 2.2 m above ground, and thus could only transfer to a moose reaching upwards, as in some browsing activities. The larvae became t