Reproductive output and larval survival of American dog ticks (Dermacentor variabilis) from a population at the northern distributional limit

The Influence of Southwestern Virginia Environmental Conditions on the Potential Ability of Haemaphysalis longicornis, Amblyomma americanum, and Amblyomma maculatum to Overwinter in the Region

“…There are more studies of the overwintering capabilities of D. variabilis than of the other invasive tick species [5,16,18,30]. Insulation and snow cover were proven to be significant factors in terms of mortality, as D. variabilis is subject to desiccation [5].…”

Interspecific differences in the questing behaviour of Dermacentor andersoni and Dermacentor variabilis (Acari: Ixodidae) larvae

“…In a montane population (i.e., collected from Kamloops, British Columbia, Canada), this larval activity extends from May to October (Wilkinson 1968). Unfed D. andersoni larvae are less tolerant to water loss than D. variabilis larvae are (Knülle 1966;Diyes et al 2021) and are unable to survive more than 10 weeks in summer (Sonenshine et al 1976). This limited off-host survival is consistent with the results of laboratory experiments that show that D. andersoni larvae survive for only 3-7 days at constant temperatures of 25 °C and 32 °C and up to 75% relative humidity.…”

“…Dermacentor variabilis larvae retain water more effectively when present in clusters (Yoder and Knapp 1999) and survive longer in moisture-rich environments (Knülle 1966;Sonenshine 1979;Diyes et al 2021). Under laboratory conditions, D. variabilis larvae produced by the adults collected from Lizard Lake Community Pasture survived for more than 100 days at constant temperatures of 25 °C and 32 °C and at least 85% relative humidity (Diyes et al 2021).…”

“…Nonetheless, the two species differ significantly in their phenology (Lindquist et al 2016). In western Canada, the larvae and, to a lesser extent, the adults of D. variabilis overwinter (Yunik et al 2015; Diyes et al 2021), whereas nymphs and adults are the overwintering stages for D. andersoni (Wilkinson 1984). In this study, we describe the differences in the behaviour of D. variabilis and D. andersoni larvae after emergence from eggs and how this relates to the differences observed in the phenology of their life cycles.…”

“…The collection site for D. variabilis in both years was Lizard Lake Community Pasture (52.405, −107.912), located approximately 50 km north of Biggar, Saskatchewan, whereas D. andersoni were collected in 2019 in an area adjacent to Chin Lakes Reservoir (49.643, −112.208) in Alberta, Canada. Conspecific male and female ticks were attached to Canadian Arcott sheep as described in Diyes et al (2021). Different sheep were used as hosts for the two tick species.…”