Data types
To investigate the relationship between the terpene content in white spruce leaves and their respective longitudes across various Canadian provinces, the study's sampling units comprise six distinct white spruce origin sites, each further subdivided into five individual replications. The primary predictor variable under examination is the geographical longitude. This variable is not subject to manipulation but is rather observed and serves as an instrumental factor in assessing its impact on terpenoid concentration. The response variable of interest is the concentration of terpenoids, encompassing measurements for 20 monoterpenes and 14 sesquiterpenes.
The secondary objective of this study is to ascertain whether variations in leaf terpene content are associated with weight loss and mortality in eastern spruce budworm larvae. The sampling units for this aspect of the research consist of 10 eastern spruce budworm larvae for each sample. The predictor variable in focus is the terpenoid concentration and it is not subject to manipulation in the eastern spruce budworm response test. This concentration is examined for its influence on ESB larvae, particularly in relation to their weight and mortality rate as the response variables of interest.
The secondary objective of this study is to ascertain whether variations in leaf terpene content are associated with weight loss and mortality in eastern spruce budworm larvae. The sampling units for this aspect of the research consist of 10 eastern spruce budworm larvae for each sample. The predictor variable in focus is the terpenoid concentration and it is not subject to manipulation in the eastern spruce budworm response test. This concentration is examined for its influence on ESB larvae, particularly in relation to their weight and mortality rate as the response variables of interest.
Raw data boxplot
Figure 7&8: Box plot about total monoterpene (left) and sesquiterpene (right) concentration of the raw data, there's an extreme value of the Upper Green River in both plots.
The raw dataset consists of concentration measurements for 20 monoterpenes and 14 sesquiterpenes in white spruce samples originating from six distinct locations across Canada. Five replicate samples represent each sampling location represent each sampling location. Concentrations are expressed in micrograms per milligram (μg/mg).
It's evident from the graphs that there is a set of extreme values in the data from Upper Green River. There's also a presence of a substantial number of minor terpenes in the original dataset, many of which were recorded as zeros, making them challenging to handle and having little impact on the overall terpene content in the leaves because the interest of the research is the total terpenoid concentration.
It's evident from the graphs that there is a set of extreme values in the data from Upper Green River. There's also a presence of a substantial number of minor terpenes in the original dataset, many of which were recorded as zeros, making them challenging to handle and having little impact on the overall terpene content in the leaves because the interest of the research is the total terpenoid concentration.
Clean data boxplots
Therefore, I retained 12 monoterpenes and 10 sesquiterpenes while removing a set of extreme data with sample order 22, associated with site ID 1321. And calculated the total concentration of monoterpene and sesquiterpene in each sample.
To make the geographical information of each sample more comprehensive, I have added the site names and the respective province, latitude, longitude, elevation, and simulated eastern spruce budworm larvae weights and survival rates for each sample in the table, along with the latitude and longitude values converted into radians. The sorted dataset and the boxplots after translation are shown in the table below.
To make the geographical information of each sample more comprehensive, I have added the site names and the respective province, latitude, longitude, elevation, and simulated eastern spruce budworm larvae weights and survival rates for each sample in the table, along with the latitude and longitude values converted into radians. The sorted dataset and the boxplots after translation are shown in the table below.
Table 2: Main dataset used for the analyses, it includes ID, genotype origin, provinces, location information like longitude, latitude and information about terpenoid concentration, Concentrations are expressed in micrograms per milligram (μg/mg).
Figure 9&10: box plots for the concentrations of total monoterpenes (left) and total sesquiterpenes (right).
Facet wrap of individual terpenoid concentrations
Additionally, I created box plots facet wrap (figure 11&12) for each monoterpene and sesquiterpene content arranged by latitude from west to east. The images depict a similar decreasing trend in the concentration of total monoterpenes and 12 individual monoterpenes and 10 individual sesquiterpenes as longitude increases from west to east. So I decided to further explore the correlation between monoterpenes and sesquiterpenes.
Figure 11&12: boxplot of the concentration of 12 individual monoterpenes (upper) and 10 individual sesquiterpenes (lower) in the order of longitude (from west to east, Alberta to Saskatchewan).
Exploratory diagrams for ESB response
Figure 13: Bar chart of larvae average weight after different treatments.
|
Bar chart of the larvae weight In examining the response of eastern spruce budworm (ESB) to terpenes, I charted the body weights of ESB larvae and controls following various treatments. The control group underwent treatment by consuming a diet devoid of needles. The graph reveals that the average weight of larvae in the control group was the highest. When juxtaposed with the box plot depicting leaf terpene content, a noticeable pattern emerges: the higher the terpene content in the diet, the lower the weight of the larvae. This observation suggests a potential negative correlation between the terpene content in the larvae's diet. Consequently, I am inclined to explore this relationship further by creating a scatterplot using this dataset in subsequent research. |
Figure 14: Scatter plot of ESB survival rate and terpenoid concentration in the diet.
|
Scatter plot of the survival rate of ESB larvae Likewise, a comparable pattern emerged in the survival rates of treated eastern spruce budworm (ESB) larvae, indicating that elevated terpene levels in the diet correlate with increased larval mortality. Consequently, I plan to delve deeper into the examination of the linear relationship between these two variables. |