Browsing by Subject "Gulf Coast tick"
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Item Male-female interaction among different geographic strains of the Gulf Coast tick Amblyomma maculatum Koch(Texas A&M University, 2006-08-16) Sleeba, Sarah BethThe overall goal of this research was to examine the interactions of adult Amblyomma maculatum Koch, the Gulf Coast tick, with respect to their utilization of hosts and to male-female cross strain interaction. Historical data along with two Petri dish experiments were used to understand male-female interaction in the field, and to determine if the aggregation attachment pheromone (AAP) produced by fed males of varying strains is attractive to geographic specific strains of unfed female ticks. It was hypothesized that questing female Gulf Coast ticks are attracted to fed males and can discriminate between grazing cattle with fed males and those without. Archival control data from ear tag studies conducted in 1985, 1987, and 1991 were analyzed to better understand female Gulf Coast tick behavior in the field relative to fed male tick presence. Females were found primarily on hosts with an abundance of male ticks, leading one to conclude that female ticks are attracted to hosts infested with male ticks. It was also discovered that females were more likely to be found on a host as the number of males on a host increased. A female??s ability to detect hosts parasitized by males likely allows them to feed and mate on-host in a fairly limited period of time. A Petri dish bioassay was used to evaluate female preference to varying geographic strains of fed males. One experiment was designed to determine if a female preferred fed males from her geographically specific strain over other males. A second experiment evaluated female response to a non-specific male in the absence of her geographically specific male. While female responses to fed males regardless of strain were higher than to unfed male control ticks, no statistical differences in female response could be determined. The Petri dish bioassay was determined to be inadequate to test female preference over several populations of pheromone producing males, and a more intensive procedure was proposed.Item Meteorological Factors Regulating the Population Expansion and Contraction of Amblyomma maculatum (Acari: Ixodidae) in Texas(2010-10-12) Coburn, Jordan McQuadeThe interaction of tick species and the microclimate that they inhabit is a subject that is frequently studied. The known biology of the Gulf Coast tick, Amblyomma maculatum Koch (Acari: Ixodidae), was used to conduct analyses to determine which meteorological factors regulate Gulf Coast tick survivorship in an area of Texas that is known for reduced occurrence of this tick species. Gulf Coast tick collection records, that indicated the collection of a single tick or multiple ticks from one animal or multiple animals at livestock markets, were obtained from the Texas Animal Health Commission. These records were used as an indicator of adult Gulf Coast tick abundance during each year in the 90 county study area and were used as the dependent variable in linear, quadratic, and cubic regression analyses. Independent variables used in these analyses were precipitation and differing drought thresholds during the peak activity time of the four life stages of the Gulf Coast tick and during combined life stage peak activity times. Linear, quadratic, and cubic regression analyses to measure the effect of precipitation during differing peak activity times of the Gulf Coast tick on adult Gulf Coast tick collection records were not statistically significant. These three regression analyses were also used to measure the effect of increasing drought thresholds, measured using a Keetch-Byram Drought Index, on adult Gulf Coast tick collection records. A determination was made that increasing drought thresholds during the peak activity time of differing Gulf Coast tick life stages reduce the number of Gulf Coast tick collection records the following year.Item Potential application of a Gulf Coast Tick, Amblyomma maculatum Koch, Aggregation-Attachment-Pheromone for surveillance of free-living adults(Texas A&M University, 2005-02-17) Kim, Hee JungThe aggregation-attachment-pheromone (AAP) of two geographic strains of the Gulf Coast tick, Amblyomma maculatum Koch, was investigated to evaluate practicality of using solid-phase-microextraction (SPME) in an AAP study of Gulf Coast tick. Solid-phase microextraction was used to compare the AAP production in two strains of fed male Gulf Coast tick and demonstrate and confirm the presence of AAP in bioassays. A solid-phase-microextraction (SPME) headspace collection technique was sufficient to capture volatile organic compounds produced by fed and unfed male Gulf Coast ticks. Gas chromatography analysis revealed three major volatile organic compounds were produced in significantly greater amounts (p < 0.05) by fed males than those produced by unfed males. These volatile compounds were produced in significantly higher amount by the third day of feeding by male ticks. However, two of these volatiles remained relatively constant in their production while the primary volatile compound increased in its production until the eighth day of feeding by male Gulf Coast ticks. Also, the relative abundances of these three volatile organic compounds were different between Oklahoma and Texas strains of Gulf Coast ticks. The activity of AAP from fed male Gulf Coast ticks was confirmed using two bioassay techniques. A petri dish bioassay revealed significantly higher numbers of female Gulf Coast ticks attracted to fed-males which also produced significantly greater amounts (p < 0.001) of volatile organic compounds detected by GC analysis. The Ytube olfactometer bioassay revealed that significantly higher numbers of females responded to fed-males or to CO2 when compared to purified air (p < 0.001), but the differences in female response to fed-males and CO2 were not significant (p < 0.391 in Oklahoma strain and p < 0.458 in Texas strain). However, female responses to stimuli containing both fed-males and CO2 were significantly higher when compared to either stimulus alone (p < 0.001).