Thesis
Putting limits on larval feeding success for the Rocky Mountain wood tick (Dermacentor andersoni)
Washington State University
Master of Science (MS), Washington State University
2015
Handle:
https://hdl.handle.net/2376/102418
Abstract
Background: Blood feeding is required for ticks to develop and reproduce, which makes feeding success vital to tick population dynamics. Larvae are the first stage of development for ticks and female "hard ticks" (Ixodidae) are able to produce thousands of larvae each. Previous experiments demonstrated positive and negative effects of density and age on feeding success of larval Rocky Mountain wood ticks (RMWT). Although age and density appear to regulate feeding success of larvae, it is unclear if these factors set absolute limits on RMWT populations. The objective of this study was to determine if the natural boundaries of age and density create absolute limits on feeding success of larval RMWTs. Methods: Infestations - Deer mice (Peromyscus maniculatus) were used as hosts for RMWT larvae. Individual mice were placed in cages containing a fixed number of unfed larval ticks. Fed ticks were recovered from the cage over a 5-day period. Feeding success was calculated as the # larvae fed/total larvae introduced. Age experiment - We hypothesized that larvae older than 6 months would be unable to feed on deer mice. Mice were exposed to 200 tick larvae that were 5-weeks post-hatch (young), or 25 weeks post-hatch (old) at the first infestation. Infestations were set on naïve mice each week over 4 successive weeks. Density Experiment - We hypothesized that mice would not support more than 250 larvae, despite exposure to ticks in excess of that density. Mice were exposed to 1000 larvae (high density) and control mice were each exposed to 250 larvae (low density). Results and Implications: Larvae older than six months could feed on deer mice, but 59% fewer fed compared to younger ticks. These results indicate that overwintered larvae (4-6 months old) would be unlikely to feed and develop into nymphs. Deer mice fed up to 350 larvae when exposed to 1000 unfed ticks, suggesting that host-parasite interaction strongly constrains the number of larvae that feed. However, the maximum number of fed larvae exceeded the burdens typically observed in the field, implying that factors before host contact also affect the probability of tick feeding success and development.
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Details
- Title
- Putting limits on larval feeding success for the Rocky Mountain wood tick (Dermacentor andersoni)
- Creators
- Samantha Lee Whiteside
- Contributors
- Jeb P. Owen (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Entomology, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525139301842
- Language
- English
- Resource Type
- Thesis