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- Presentation Type: Dissertation Defense
- Date: 10/30/2019
In 2006, Leon G. Higley noted a tiger beetle species, Cicindela haemorrhagica, walking and feeding in thermal pools of Yellowstone National Park (YNP). Although this species was first recorded in the park more than 100 years ago (Hubbard, 1891), its distribution, ecology, and association with thermal features are not known. In this study, we examined its distribution, abundance, and habitat characteristics to determine if they are exclusively associated with thermal springs and to determine the physical and chemical extremes in which these beetles can live. We transcribed their behavior to determine if they use thermoregulatory behavior to cope with the high temperatures associated with thermal springs. Lastly, we studied their lethal thermal maxima to determine if they have an increased thermal tolerance, which indicates a structural or physiological adaptation. Our results show that C. haemorrhagica are seemingly exclusively associated with thermal springs and are habitat (thermal spring) generalists. Springs range between pH 2.73 and 9.0, temperatures of 29.1 oand 70 o, and varying metal concentrations. However, all thermal springs were surrounded by barren soil with a gradual edge (gentle slope) towards the thermal water. We propose census and observations as the best methods to estimate the abundance for highly mobile species near thermal springs. Conservative population sizes of C. haemorrhagica ranged between 500-1500 individuals for thermal springs within YNP.
Cicindela haemorrhagica populations not associated with thermal springs have a strong positive correlation between thennoregulatory behavior and temperature (Pearson Correlation Coefficient = 0.276, p= 0.0127). In contrast, C. h. haemorrhagica populations inside YNP have a strong negative correlation between thermoregulatory behavior and temperature (Pearson Correlation Coefficient= -0.224, p= 0.0001). Interestingly, the YNP populations thermoregulate to heat up at cold temperatures, but do not use this strategy to cool off at high temperatures. To our knowledge, there is no other example of dramatically different behaviors between two populations of insects in the same species. This may indicate a thermophilic adaptation of these beetles to the thermal springs of YNP. However, the lethal thermal maxima of YNP C. h. haemorrhagica (50.41 oC +/- 0.26) is only 1.08 oC higher than non-thermal spring C. h. haemorrhagica ( 49.33 oC +/- 0.20) (Mixed model, p= 0.0023). Although these lethal thermal maxima are a new record for reproductive metazoans, it is not high enough to explain its occurrence at thermal springs as much as 70 oC.
These results indicate that C. haemorrhagica filled a new niche inside Yellowstone National Park where the benefits (i.e. carrion drifting ashore, high temperatures during the winter, reduced competition, among others) outweighed the costs (i.e. high temperatures, pH, and heavy metals). These beetles were able to adapt to the extreme conditions of the thermal springs in YNP causing them to behave differently than other tiger beetles, including C. haemorrhagica outside YNP. We can conclude that the mechanism used by these beetles are not behavioral nor physiological, but are more likely to be structural.
- Presentation Type: Thesis Defense
- Date: 3/19/2015
The American burying beetle, Nicrophorus americanus Olivier, is the largest North American member of the Silphidae. It was declared federally endangered in 1989 and many efforts to prevent this species from going extinct are ongoing. The Nicrophorus beetles bury small carcasses for reproductive purposes. They also reside in the soil during times of daily and seasonal inactivity. To better understand why the American burying beetle is in decline, the importance of texture, moisture, vegetation, and gravel, the burial depth, and the effect of compaction on their burying behavior were examined.
- 2019 – Meritorious Graduate Student awarded by School of Natural Resources, UNL
- 2019 – Teaching Assistant Holling Family Award awarded by Institute of Agriculture and Natural Resources
- 2018 – Milton E. Mohr Fellowship awarded by UNL center for Biotechnology
- 2018 – Science Slam - First place awarded by Nebraska MRSEC
- 2017 – SNR GSA Travel Grant awarded by School of Natural Resources -Graduate Student Association
- 2016 – UNL Science Slam - Finalist awarded by Nebraska MRSEC
- 2016 – Elevator Speech Contest - Ph.D. First Prize awarded by School of Natural Resources
- Applied Ecology
School of Natural Resources - Graduate Student Association
- SNR GSA
- Fundraising Chair 2016-2017
School of Natural Resources Graduate Student Association
- Co-Chair 2017-2018
SNR Extended Mission Area Applied Ecology
- Graduate Student Representative 2016-2017
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