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    Off-Host Biology and Ecology of Immature Gulf Coast Ticks (Amblyomma Maculatum Koch) in Mississippi

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    etd-03242017-032555.pdf (5.920 Mb )
    Author
    Portugal, Jose Santos
    Item Type
    Dissertation
    Advisor
    Goddard, Jerome
    Committee
    Varela-Stokes, Andrea S.
    Baker, Gerald T.
    Harris, Jeffrey W.
    Schneider, John C.
    Metrics
    
    Abstract
    Little is understood about off-host behavior and ecology of immature Amblyomma maculatum Koch (Gulf Coast tick). A more complete understanding of this tick is essential to protect human and animal health. My research focused on seasonality and distribution of immatures in Mississippi, potential suitability of some insect and human hosts to larvae, and aspects of nymphal questing behavior. A single larva was collected (third off-host collection reported) when sampling A. maculatum habitat using a novel device. Collection of this larva in November expands the stage’s known seasonality and confirmed a prediction concerning seasonality of larval A. maculatum. Low frequency of immatures (8.3%) confirmed that they’re incredibly difficult to collect off-host. Nymphal collections peaked in March, and known seasonality was extended for both nymphs and adults. I examined known records, elucidating seasonality and distribution of A. maculatum in Mississippi. Either multiple generations per year or diapause are responsible for observed bi-modal distribution of immature collections. Additionally, I compiled the most extensive host record of immature A. maculatum in Mississippi and investigated seasonality patterns using USDA plant hardiness zones. I compiled the most complete record of ticks found on arthropods. Amblyomma americanum and A. maculatum were both confirmed to crawl onto arthropods, giving support to occasional, unintentional dispersal by phoresy. There was no conclusive evidence that larval A. maculatum feed on arthropods, however data supported feeding by larval A. americanum. These results have interesting implications regarding evolution of pathogens/endosymbionts. I provided the first evidence that larval A. maculatum can attach to humans. Rickettsia parkeri, a human pathogen transmitted by this species has recently been shown to be capable of transovarial transmission. Therefore, larval A. maculatum may provide another avenue of transmission. I have demonstrated that A. maculatum are difficult to collect off-host in part because they prefer to quest low to the ground. In choice studies, 5-cm-tall stems were most likely to be occupied by nymphs released into an array of stems. Low vapor pressure deficit encouraged questing, while higher VPD and warmer temperature increased questing height. These results may have implications in understanding host-seeking behavior in other tick species as well.
    Degree
    Doctor of Philosophy
    Major
    Entomology
    College
    College of Agriculture and Life Sciences
    Department
    Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology
    URI
    https://hdl.handle.net/11668/17772
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    Mississippi State University Libraries
    395 Hardy Rd
    P.O. Box 5408, Mississippi State, MS 39762-5408
    (662) 325-7668
    (662) 325-0011
    (662) 325-8183
    Contact repository admin Report a problem Terms of use Privacy policy Accessibility MSU Legal
     

     

    Mississippi State University Libraries
    395 Hardy Rd
    P.O. Box 5408, Mississippi State, MS 39762-5408
    (662) 325-7668
    (662) 325-0011
    (662) 325-8183
    Contact repository admin Report a problem Terms of use Privacy policy Accessibility MSU Legal