Off-host survival of Dermacentor variabilis (Acari: Ixodidae) adults near their northern distributional limit in Saskatchewan, Canada.
J Med Entomol
; 60(6): 1288-1296, 2023 11 14.
Article
em En
| MEDLINE
| ID: mdl-37589670
ABSTRACT
Dermacentor variabilis (Say) is expanding its range northwards in Saskatchewan and Manitoba (Canada). Knowledge of the relative ability of different life cycle stages to survive off-host over winter is important for assessing the potential for further range expansion and risk of pathogen transmission. In the present study, the off-host survival of D. variabilis adults was determined in outdoor terraria within a field plot close to Lizard Lake Community Pasture (LLCP) situated near the northern distributional limit in Saskatchewan. Only a small proportion (7%) of adult ticks in this relatively recently established population survived from mid-summer to late winter. Off-host survival had declined further to <4% by mid-spring. A significantly greater proportion of female ticks (6%) survived from mid-summer to mid-spring than did male ticks (1%). The supercooling points (SCPs), the temperature below 0 °C when body fluids spontaneously freeze, of the 17 ticks that survived through to mid-spring did not differ significantly from the SCPs of questing ticks in the previous summer, suggesting adult D. variabilis do not undergo cold hardening during winter diapause. The off-host survival of D. variabilis adults near LLCP was also much lower than that previously reported for adults from Sandy Hook in Manitoba, a population that has been established for decades. This finding suggests that there is geographical variation in the ability of D. variabilis in southern Canada to survive from mid-summer to the subsequent spring. However, the ecological and genetic factors influencing the survival of northern populations of D. variabilis requires further investigation.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ixodidae
/
Dermacentor
Limite:
Animals
País/Região como assunto:
America do norte
Idioma:
En
Revista:
J Med Entomol
Ano de publicação:
2023
Tipo de documento:
Article