A Study in the Ecosystems of Aquatic Insects

Timothy Breihan
Andrew Davis
Christopher Haedt
Michael Loeffelman

A Study in the Ecosystems of Aquatic Insects

Introduction

The pervasive view of the world around us is one utter chaos, a jumbled amalgam of random confusion and disarray. Upon stepping from our climate-controlled domiciles into the irrationality of nature, we are likely to observe our bucolic surroundings with disdain and think to ourselves, "How lucky I am to be an a Homo sapiens, living apart from all of thisómess! No crawling about in the dirt for me!"

As much though weíd like to believe that our superior human intellect brought order to this blasted wilderness, we are really neíer too clever.

In fact, there is a field of theoretical mathematics, known informally as chaos, whose sole focus is to describe the highly complex, albeit dissonant order that ultimately represents nature as a whole. Order, you may ask yourself, but there is no order to nature! Nature is, by its very essence, the epitome of disorder! Natural selection? The random elimination of the unfit and unadaptable. Weather? Entirely unpredictable. Time?

Well thatís the exception, you will tell me. Time is order at its most perfect resolution. What are the most precise of our inventions meant to measure? Well, time, of course! From a Rolex watch to a microprocessor, all of our greatest inventions are nothing more than imperfect attempts to conquer the perfection of that which dictates both our seasons and our schedules.

But where then, may I ask does our sense of time come from? Simple, you would reply, from the earthís rotation about the sun. A precisely timed journey lasting three hundred and sixty-five days, six hours. Of course, the inconvenience of that additional six hours is simple shaved off and the deficiency is made up by adding an extra day every four yearsÖ

But, I would tend to interrupt at this point, is not the earthís rotation about the sun part of nature as well? For, in nature, there are no exceptions, just a single, big picture for us to view at various degrees of resolution.

Regardless of our realizations, we exist as a tiny and highly organized fragment of an enormous and equally organized universe. Chaos mathematics illustrates this much. In the most macroscopic of terms, we see how galaxies cluster in orbital systems, clouds composed of clouds composed of hundreds of trillions of stars. We see that galaxies themselves rotate, their spindly arms orbiting dense clusters of matter at their centers, and that these stars, too numerous to comprehend by any observable standard, act as the anchors for their own orbital systems, solar systems, as we shall call them. On at least one of these solar systems, dangling from the extremity of one of a relatively minor galaxyís appendages exists a satellite that bears carbon-based life. Most extraordinary of all, however, is that these life forms, in all of their diversity, may be broken down into only a handful of elements, whose particles, much too miniscule to be seen with even the most powerful microscope, are composed of only three particles, clustered and rotating about each other, hundreds of trillions of individual universes contained within our bodies.

This explanation is, of course, both poetic and simplistic, but, as such things usually do, speaks volumes of the interconnectedness of all aspects of nature. Nature on its most minute scale is simply a reflection of nature on its most massive.

It seems only fitting, then, that in a course entitled "From the Universe to the Duck Pond," that these interrelations should be discussed. Our lab, therefore, will focus on a small and self-contained ecosystem, easily observable and yet highly complex. Through the processes outlined, below, we will gain not only an understanding of the diversity, structure, and determinate factors within our subject ecosystem, we will also gain knowledge that will help us to understand the systems present in ecology on a larger scale.

Objective

Our primary objective in the organization and execution of our experiments consists of a quantitative and qualitative study of the number and diversity of species of aquatic insects in the Western Pond. An artificially created freshwater body, Western Pond provides a nearly ideal platform for extended observation. It is entirely self-contained, minimizing the effects of large chemical, temperature, and pH shifts from external water sources that creeks and stream-fed ponds are sometime subject to. Furthermore, the pond contains two distinct areas, an underdeveloped region, bordered by a dense thicket of deciduous, secondary growth trees, and a developed region, bordered by a cultivated lawn.

Our activities will attempt to determine the specific ecological qualities of each region and the manner in which these unique conditions affect the number and diversity of the aquatic insect populations that inhabit them.

Our observations will seek to ascertain data from two separate aspects of the question at hand:

First, to determine the environmental conditions present in the two aforementioned ecosystems, including sediment level and structure, water temperature, water pH, and dissolved oxygen levels, and

Second, to gather quantitative and qualitative data on the insect populations present in these two aforementioned ecosystems.

Hypothesis

Given the environmental variance of the area immediately surrounding the Western Pond, and

Given that one area of the pondís surrounding is more densely populated by secondary-growth tress, and

Given that an increased amount of trees would lead to greater leak accumulation in the areas of the pond immediately adjacent, and

Given that increased leaf accumulation would result in increased decomposition, and

Given that increased decomposition would result in
1) Greater sediment accumulation, and
2) An increase in water temperature, and
3) An increase in water acidity, and
4) A decrease in the dissolved oxygen content of the water;

We propose that insect populations in the area of the pond adjacent to the trees will be adversely affected, in both number and diversity, by the aforementioned conditions present in this ecosystem.

Resources
& Materials

Sediment corers
Collection vessels
Strainers
Microscopes
Aquatic insect keys
Thermometers
Hot kit tests for the following:
Water pH
Dissolved oxygen

Procedure & Methods

The execution of this study will take place in two distinct phases, with a third phase of data analysis. The first of these will involve only our groups members and will take place on a weekly basis from the date of proposal acceptance to roughly one week prior to the due date of the final report. The second will take place on the scheduled class day, and will involve all students in Section D of the Natural Systems 121/123 class.

Phase One: A Study of the Ecosystems of Western Pond

A pair of test sites shall first be selected, one adjacent to the wooded area along the eastern edge of the pond, and one adjacent to the cultivated lawn on the western edge of the pond. The tests in this phase will be performed on a weekly basis, from the date of proposal acceptance to roughly one week prior to the due date of the final report. These tests will be performed by the group only.

Test One: Temperature

Using a thermometer, the water temperature of each test site shall be measured and recorded. This test will be performed twice a day, in both the mid-morning mid-afternoon, as to best minimize the affects of direct sunlight or shade on the water temperature.

Test Two:Dissolved Oxygen

Using a hot kit, the dissolved oxygen level of the water of each test site shall be measured and recorded.

Test Three: Water pH

Using a hot kit, the pH level of the water of each test site shall be measured and recorded.

Test Four: Sediment Structure

Using a sediment corer, a sample of the sediment at each test site shall be taken and photographed for record.

Phase Two: A Quantitative and Qualitative Study of the Aquatic Insects of the Test Sites

Prior to the date of the class experiment, the procedure below will be performed by the members of our group alone, in an attempt to minimize the margin of error intrinsically present when a large group of assistants is utilized.

On the assigned day of the class experiment, the class will be broken down into a number of small groups, each containing three or four students. Each group will be given a collection vessel, strainer, and identification key of aquatic, freshwater insects.

At the pond, each group will be assigned to one of the two test sites. At their respective sites, the groups will take samples of the sediment in their collection vessels.

After samples are collected, the groups will begin to strain the sediment. Water and silt will be discarded, while larger solid matter will be kept for observation.

Groups will then examine the solid matter, looking for aquatic insects that may be inhabiting it. Aquatic insects shall be collected.

Utilizing identification keys, students will attempt to identify the genus and species of insect found. This data, along with the number of insect found, shall be recorded for analysis.

The remaining solid matter will then examined under a microscope for further insect life. Quantitative and qualitative exercises described above will be repeated.

Timeline October 11: November 8:
Phase One Phase One

October 18: November 15:
Phase One Phase One
Phase Two
November 22:
October 25: Phase One
Phase One
November 29-December 7:
October 26: Phase One
Class Day Data Analysis
Final Report
November 1:
Phase One

References & Works Cited

Beroza, Morton: Chemicals Controlling Insect Behavior. New York.
Academic Press. 1970.

Cummins, Kenneth W. & Merritt, Richard W.: An Introduction to the
Aquatic Insects of North America. Dubuque, Iowa. Kendall/Hunt Publishing Co. 1996.

Lanham, Url: The Insects. New York. Columbia University Press. 1964.

Lehmkuhl, Dennis M.: How to Know the Aquatic Insects. Dubuque,
Iowa. Wm. C. Brown and Co. Publishers. 1979.

Pimentel, David: Insects, Science, and Society. New York. Academic
Press, Inc. 1975.

Resh, Vincent H. & Rosenberg, David: The Ecology of Aquatic Insects.
New York. Praeger Scientific. 1984.

Samways, Michael J.: Insect Conservation Biology. London. Chapman & Hall. 1994.

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