TY - JOUR
T1 - Off-host survival of blacklegged ticks in eastern North America
T2 - A multistage, multiyear, multisite study
AU - Brunner, Jesse L.
AU - LaDeau, Shannon L.
AU - Killilea, Mary
AU - Valentine, Elizabeth
AU - Schierer, Megan
AU - Ostfeld, Richard S.
N1 - Publisher Copyright:
© 2023 The Authors. Ecological Monographs published by Wiley Periodicals LLC on behalf of The Ecological Society of America.
PY - 2023/8
Y1 - 2023/8
N2 - Climatic conditions are widely thought to govern the distribution and abundance of ectoparasites, such as the blacklegged tick (Ixodes scapularis), vector of the agents of Lyme disease and other emerging human pathogens. However, translating physiological tolerances to distributional limits or mortality is challenging. Ticks may be able to avoid or tolerate unsuitable conditions, and what is lethal to one life history stage may not extend to others. Thus, even after decades of research, there are clear gaps in our knowledge about how climatic conditions determine tick distributions or patterns of abundance. We present results from a 3-year study combining daily hazard models and data from field experiments at three sites spanning much of I. scapularis' current latitudinal distribution. We examine three predominant hypotheses regarding how temperature and vapor pressure deficits affect stage-specific survival and transition success and consider how these results influence population growth and distribution. We found that larvae are sensitive to temperature and vapor pressure deficits, whereas mortality of nymphs and adults is consistent with depletion of energy reserves. Consistent with prior work, we found that overwinter survival was high and successful stage transitions (e.g., fed nymphs molting to adults) were sensitive to temperature. Collectively, results from this comprehensive, multiyear, multistage field study suggest that population growth of I. scapularis is less limited by restrictive climatic conditions than has been broadly assumed, although influences on larval survival may slow tick population growth and establishment in some desiccating conditions. Further studies should integrate climate effects on stage-specific survival to better understand these effects on population dynamics and range expansion in a changing climate.
AB - Climatic conditions are widely thought to govern the distribution and abundance of ectoparasites, such as the blacklegged tick (Ixodes scapularis), vector of the agents of Lyme disease and other emerging human pathogens. However, translating physiological tolerances to distributional limits or mortality is challenging. Ticks may be able to avoid or tolerate unsuitable conditions, and what is lethal to one life history stage may not extend to others. Thus, even after decades of research, there are clear gaps in our knowledge about how climatic conditions determine tick distributions or patterns of abundance. We present results from a 3-year study combining daily hazard models and data from field experiments at three sites spanning much of I. scapularis' current latitudinal distribution. We examine three predominant hypotheses regarding how temperature and vapor pressure deficits affect stage-specific survival and transition success and consider how these results influence population growth and distribution. We found that larvae are sensitive to temperature and vapor pressure deficits, whereas mortality of nymphs and adults is consistent with depletion of energy reserves. Consistent with prior work, we found that overwinter survival was high and successful stage transitions (e.g., fed nymphs molting to adults) were sensitive to temperature. Collectively, results from this comprehensive, multiyear, multistage field study suggest that population growth of I. scapularis is less limited by restrictive climatic conditions than has been broadly assumed, although influences on larval survival may slow tick population growth and establishment in some desiccating conditions. Further studies should integrate climate effects on stage-specific survival to better understand these effects on population dynamics and range expansion in a changing climate.
KW - arthropod vector
KW - climatic conditions
KW - survivorship
KW - temperature-dependent development
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U2 - 10.1002/ecm.1572
DO - 10.1002/ecm.1572
M3 - Article
AN - SCOPUS:85153588974
SN - 0012-9615
VL - 93
JO - Ecological Monographs
JF - Ecological Monographs
IS - 3
M1 - e1572
ER -