Off-host survival and reproductive success of adult female winter ticks, Dermacentor albipictus in seven habitat types of Central Alberta

Abstract

Winter tick is an important pest of moose which affects the physical and physiological well-being of moose. All moose in Alberta become infested with winter ticks every year and suffer morbidity and mortality from the infestation. The ticks are acquired in autumn in the habitats of EINP during search for food and other ecological needs. When blood-engorged female winter ticks, Dermacentor albipictus, drop from moose in March-April, they have little choice in where to oviposit, because their dispersal is minimal. The habitat in which they drop is the habitat in which they must survive and produce offspring. Different habitats with different microclimatic conditions influence survival and reproduction of winter ticks differently. Off-host survival and reproductive success of adult female winter ticks were determined in 7 habitat types of Elk Island National Park, Central Alberta, 1992. Adult ticks, in gauze bags, were placed at ground surface in late April and monitored for survival, egg-laying and larval survival to November. Generally, more ticks survived to produce eggs that hatched to larvae and the larvae survived longer, in habitat types with open canopies (rank in order: upland shrub, grassland, open aspen), where ground-litter temperatures in summer were higher, than in habitat types with closed canopies (labrador tea, spruce forest, willow shrubland). Results may explain why moose, Alces alces, in Alberta that live in areas with open canopies (i.e., aspen parkland and southern fringe boreal forest) appear to suffer more from winter ticks than moose living in spruce-dominated boreal mixed wood forests. Moose in these areas probably acquire more ticks.


(Journal of the Ghana Science Association: 2001 3(3): 109-116)