The Great Grasshopper Adventure

Introduction

Purpose/Problem. What is your hypothesis?
Our project originated as an inquiry into the SLOSS debate presented by David Quammen in The Song of the Dodo. We were going to sample a variety of sizes of habitats within a local farm to determine the number and diversity of insect species present there. Due to early frosts that hampered our data collection, we modified our inquiry to look at a single species: grasshoppers. Instead of sampling grasshoppers in a variety of sizes of habitat, as originally planned, we thought it would be interesting and valuable to sample the number of grasshoppers present at regular intervals away from a fencerow present at our sampling site. Our question is, therefore, does the number of grasshoppers vary as habitat gets farther away from the fencerow?
Our hypothesized conclusion is that there will be a difference in grasshopper numbers as habitat gets farther away from the fencerow. Due to the increased shelter provided by both the fence and the higher grass under the fence, there will be a greater number of grasshoppers underneath the fence and fewer grasshoppers in the sampling sites away from the fencerow.

How did you decide on this project? How did you decide upon your specific questions?
The SLOSS question and the inability of respected scientists to reach any kind of conclusion on the matter intrigued all three of us. Although we are not so presumptuous as to think that our class research project could reach a definite conclusion that has eluded scientists for decades, we embarked on this project with the hope of acquiring a greater understanding of the issue for ourselves. Our specific question about the grasshoppers arose because we were interested to discover whether or not proximity to a major landmark or habitat divider (like a fencerow) would influence species abundance. While this issue does not directly relate to the SLOSS question that originally drove our research, we hoped that it would provide us with a greater understanding of habitat issues in general.

What do you plan to accomplish?
On a task level, we plan to conduct a statistically sound research sampling of grasshoppers in our selected sampling site. On a conceptual and educational level, we hope to learn a significant amount about the ecology and habitat patterns of grasshoppers and then apply this information to a greater understanding of habitat issues.

Relevance, if any. Why is this research interesting?
We are interested in this research question because it has to do with the relationship between and organism and its environment. The landscape of an environment most certainly affects the behavior, ecology, and habitat patterns of organisms. This project investigates the relationship between grasshoppers and a fencerow in a grassy field, which should shed light on the general relationship between an organism and its environment.

Relevance of research question

Literature Reviewówhat have others done?
The most significant and comprehensive work on grasshoppers has been conducted by Sir Boris Uvarov (1888-1970). His two-volume opus entitled Grasshoppers and Locusts: A Handbook of General Acridology covers everything from anatomy and physiology to mating patterns and gregarious behaviors. He addresses grasshoppersí relationship to their environment fairly extensively in the second volume of his work. In his discussion, he reports that grasshoppers tend to live in very close proximity to some sort of shelter, whether natural or artificial. Though not backed up with any case research, his conclusions are based on general observations over a long period of time.
No other field research of a similar sort to our project could be found.

How does your research relate to larger questions? What contribution will your project hopefully be able to make to the broader base of human knowledge?
An understanding of an organism and its relationship to its environment will enable us to learn how to continually adapt to our own environment. Our research deals with a complex and fundamental interrelationship in nature and it is necessary to continually explore natural interrelationships if we are to remain active participants in our own biosphere.

Materials and Methods

What is your experimental design? What are the reasons behind the different parts of your experimental design? Why are or arenít you doing certain things?
Our field research was conducted at a grassy field on the east side of Route 27, approximately 3 miles north of Oxford (see attached photographs). A mostly-circular fence encloses the field and provided the basis for our sampling. Five distances were randomly selected using a random number generator and measured along the fence starting from an arbitrary zero point. The five locations indicated by the randomly-selected distances then became our sampling sites, A through E. At each sampling site, five grasshopper counts were taken (plots 1 through 5): one directly underneath and within two and a half feet on either side of the fence, two between 2.5 and 7.5 feet away from either side of the fence, and two between 7.5 and 12.5 feet away from either side of the fence (see diagram below).

This site was then visited on ten separate dates. During each visit, twenty-five grasshopper counts were taken: a count at plots 1 through 5 for each of the five sampling sites (A through E). Therefore, at the end of our ten visits we had gathered 50 grasshopper counts for each of the sampling sites (ten for each of the five plots).

Is your experimental design statistically sound? How do you know? Did you ask for advice?
Our experiment was statistically sound for a number of reasons. First, we gathered a significantly large number of samples for each site so that the data was a reliably adequate reflection of the true number of grasshoppers in the area. Second, at least two grasshopper counters were present at each of our data collecting visits. Having two people counting ensured that we did not miss any insects, making our data as close to reality as possible. Finally, the random selection of our five sampling sites made sure that our samples were an accurate representation of the entire field. The sites ended up being fairly evenly spaced out, giving us the advantage of a wide geographic sampling area.
When it came to processing our data using a statistical computer program, we enlisted the help of professor Hays Cummins. He instructed us on the use of the StatView statistics program and showed us how to glean significant information from our raw data. Haysí help was important to our final results because we were able to do much more with the data than we would have been able to do on our own.

How will you ensure unbiased results?
Two main factors in our experimental design ensured unbiased results. First, since at least two samplers were present at each data collection session, an accountability relationship was present at all times. We kept each other honest and accurate when recording the data. Second, all of our conclusions were based primarily on the statistical analysis of the collected data. We had no chance to manipulate or change the data, and whatever the statistics program came up with we had to abide by. The statistics themselves ensured an unbiased experiment.

How will you ensure that the data collected by the class can be trusted?
No data was collected by the class.

Will you adequately demonstrate your data collection methods and the importance of consistency?
Our data collection methods are described above and will be demonstrated during the class presentation.

Describe important materials and how they were used.
Measuring tape- used to measure along the fencerow to determine the locations of the five sampling sites. Also was our tool for measuring perpendicularly away from the fence to locate the five plots at each of the sampling sites.
Data sheets- used to record grasshopper numbers at all plots (see attached data sheets).
Digital camera- allowed us to take pictures of the sampling field

Have you included a Data Sheet?
Yes. Our data sheets are attached to this report.

Include a specific timeline of research execution.
10/10: Site survey and preliminary experimental design
10/14: First data collection
10/17: Second data collection
10/20: Third data collection
10/23: Fourth data collection
10/28: Fifth data collection
10/31: Sixth data collection
11/4: Seventh data collection
11/7: Eighth data collection
11/11: Ninth data collection
11/16: Tenth data collection
11/29: 8pm, met with Hays Cummins at the computer lab in Boyd Hall to work on
statistical analysis of data in StatView

Results

Observations
Plot 3 showed the largest number of grasshoppers consistently over all eight sampling periods and at all five sampling sites. This data indicates that plot three has some significance in determining the habits and habitat preferences of grasshoppers.
The number of grasshoppers fount per plot decreased at a relatively steady rate as one moved to the right or left of plot three. This indicates that plot three is somehow attractive to grasshoppers.
The number of grasshoppers found in plots 2 and 4 were very similar, as were the numbers from plots 1 and 5. Grasshopper numbers therefore decrease at a steady rate on both sides of the fence. Distance from plot 3 and the fencerow is definitely a factor in determining grasshopper numbers.
Neither time of sampling or location of the sampling sites were found to be major factors in the number of grasshoppers found in any of the plots. Therefore, distance from the fencerow (plot 3) was found to be the most significant determinant of grasshopper numbers.
Time varied only slightly from 2.75 to 3.25, making it unlikely that temperature or other seasonal factors were significantly influencing the grasshoppers.
Sampling site varied even less throughout, but was from 3.0 to 3.25, indicating that grasshoppers were evenly distributed in the area sampled.
When sampling site and time were compared against each other, the largest difference was by one grasshopper, which is insignificant and warrants no conclusions.
A Plot by Time analysis indicated that some trend may be present as the number of grasshoppers in plot three increased from the last sample taken. The majority of other plot numbers also increased along with time. When the numbers of grasshoppers in plot 3 decreased, the other plot numbers followed suit, decreasing at a similar rate. This pattern was followed in all of the sampling times except from 10/23-10/28 and 7/11-11/11. From 10/23-10/28, two plot numbers remained the same while plots 2 and 3 increased and plot 4 decreased. From 7/11-11/11, there was no change in the number of grasshoppers in plot 3.

Think about how best to convey your findings. What types of statistics will be of use to you. Why? How will you best display your results? (Graphs, tables?)
When statistically analyzing the data, three comparisons were of primary importance.
As a starting point, abundance of grasshoppers was analyzed as compared to plot, sampling site, and time of sampling. Trends in these single variables were observed and are depicted in the graphs on the following pages.
In an attempt to identify some underlying trends in the data, abundance was compared over a sampling site/time graph (see following pages)
Plot vs. Time showed us whether or not there was any relationship between the number of grasshoppers at each site and the time of year when the samples were taken (see following pages)

Discussion and Conclusions

Based on your background research, your own project, and analysis of the data, explain why you got the results you did.
Uvarov explains that "it is a common experience of grasshopper collectors and of students of their populations that an abundant species may occur over an apparently ecologically uniform area not at an even density, but in more or less discrete, though loose, groups. Such a patch distribution may be due to someÖecological pattern within the habitat (p. 142). In the context of our research, the "ecological pattern" present was clearly the existence of the fencerow in the field. The influence of the fencerow in grasshopper habitat affected the number of grasshoppers present in different parts of the field. There are a number of possible explanations for the influence of the fencerow on grasshoppers.
The most likely explanation has to do with grasshoppers affinity for dense shelter. Since it is very difficult to trim the grass directly underneath the fence, it had grown much taller than the wild grasses away from the fence. These thick grasses provide a perfect shelter and camouflage environment for the grasshoppers. They will be much more likely to hang out under the fence because of this added shelter. It was more difficult to count grasshoppers in plot 3 right underneath the fence because of the thick grass cover.
Another explanation deals with grasshoppers tendency to hang on vertical objects instead of standing horizontally on the ground. Many of the grasshoppers under the fencerow were found directly on the fenceposts and on the larger blades of grass. The abundance of places to "hang" under the fencerow makes plot 3 much more attractive to grasshoppers than the other four plots away from the fence, which have neither posts or thick blades of grass on which to perch.
A third possibility could relate to grasshopper feeding preferences. Most grasshoppers prefer to feed on tall, vertical blades of grass as opposed to shorter, horizontally-oriented blades (Uvarov, p. 82). It would therefore make sense to find more grasshoppers near the fence, where the food supply is taller and more vertical.

Think beyond the project. How does your work fit in with what others have done? What additional questions do you have?
Our work is consistent with Uvarovís findings that grasshopper populations tend to vary in density and abundance based on environmental factors present in their habitat. In a general habitat-understanding perspective, this experiment has shed a greater light on the relationship between an organism and its environment. By understanding special habitat features and how these features interact with the ecological habits of a particular animal, it is possible to more fully understand the behavior and ecology of the animal.
The most sweeping question generated by our research has to do with time. Our samplings took place over approximately a six-week period in October and November. It would be extremely informative to take samples at our sites for a full year. By doing this, we will not only be able to observe evidence of grasshopper relationship to the fencerow, but also of seasonal weather influences and how they affect grasshopper abundance.

Literature Cited

Uvarov, Sir Boris, Grasshoppers and Locusts: A Handbook of General Acridology.
Centre for Overseas Pest Research: London. 1977.
www.sdvc.uwyo.edu/grasshopper/facttoc.htm
www.ianr.unl.edu/pubs/insects/g791.htm
www.highlands.w-cook.k12.il.us/Prarie/INSECTS/Grasshopper
members.aol.com/eduscience

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