Characteristic Of Termites As A Eusocial Group Of Insects

Abstract

Termites are a blind eusocial group of insects that excrete trail pheromones from their sternal glands allowing them to participate in foraging behavior. A recognized North American termite colony, Reticulitermes flavipes, is known to contain a chemical, 2-phenoxyethanol, within their trail pheromones that is also found within the ink of various types of pens. Using the workers within the R. flavipes colony, it was determined if a pen and circle track had any influence upon the trail following behaviors, compelling the workers to stay on these two tracks for a longer period of time without wandering off. The trail following patterns of R. flavipes workers was observed within this study by comparing a pen track against a sharpie track and a circle track against a square track. After collecting our individual and overall class times, the recorded data was statistically analyzed. The two-sample t-tests of both the individual and class data for the pen track against the sharpie track indicated that there was a significant difference between the two tracks. The two-sample t-tests of the individual data for the circle track against the square track indicated that there was no significant difference made between the two tracks, while the class data for the circle track against the square track indicated there was a significant difference made between the two tracks.

Introduction

Termites are a eusocial group of insects that has been successfully prevailing on earth for millions of years. Termites play a role in the ecological community as their ability to feed on wood and their sophisticated colonial organization can become hazardous to our way of life. This species is evolutionarily known to be a part of the order Isoptera with various families, including Reticulitermes. The Reticulitermes family represents an important genus of termites that contain multiple pest species. One of these pest species that is found within North America are Reticulitermes flavipes. R. flavipes is one of many colonies that possesses a simple organization of being split into three different castes that include soldiers, workers, and reproductives. The soldiers are seen to be larger in size, to possess a pair of extremely elongated mandibles, and to possess frontal exocrine glands. Within the colony, the soldiers job is to provide protection for the rest of the colony as they are able to discharge defensive chemicals from their exocrine glands and provide mechanical defense using their mandibles. On the other hand, the workers are seen to be smaller in size and they do not possess a pair of mandibles either. Within the colony, the workers maintain helping behaviors such as feeding, tunneling, and offspring tending to. Termites are notoriously recognized as blind insects that rely on other senses. As they live in complete darkness within their underground tunnel network, termites produce trail pheromones from their sternal glands that allow them to communicate and take part in foraging behavior. Pheromones are chemicals produced for communicational purposes. Specifically, trail pheromones are secreted for orientation and signaling for exploration of food resources. R. flavipes trail pheromones contains a chemical called 2-phenoxynethanol. 2-phenoxynethanol is a colorless type of alcohol that contains a pleasant odor. This chemical makes it easier for R. flavipes workers to follow the trails left behind from the trail pheromones that were excreted by previous workers. 2-phenoxyethanol is also found in various types of common used pens, which can mimic the odor that is left behind by the trail pheromones.

In this study, we will be examining the workers of Reticulitermes flavipes as we observe their trail following behavior patterns. The goal of this study is to see whether or not the common 2-phenoxynethanol chemical that is found not only in the trail pheromones, but in common used pens will have an effect on R. flavipes trail following patterns. In addition, the second goal of this study is to see if a square or circle shaped track will have an impact on their trail following as the tracks mimic the tunnels R. flavipes make. By testing a pen against a sharpie and a drawn square against a circle tract, we will be able to observe if R. flavipes workers will follow the pen as well as the drawn circle track longer and more efficiently, presenting a positive impact on their trail following behavioral patterns.

Materials and Methods

Preparation of Pen vs Sharpie Test

Using an 8.5 X 14 inch white paper, draw a 3X3 inch square with a blue Bic pen and draw a second 3X3 inch square using a blue Sharpie marker in the middle of the paper. These two squares will be the test tracks for the termites to follow. Within test tube one there should be about 30 worker Reticulitermes flavipes termites, a wet paper towel, and a cap that seals the test tube. Test tube one will be known as the untested or unused worker R. flavipes test tube. Within test tube two there should just be a small piece of wet paper towel and a cap that seals the test tube. Test tube two will be known as the tested or used worker R. flavipes test tube. The wet paper towel is placed within the test tube to give the termites a wet environment giving them a longer survival time. Make sure you have two timers, one that will be used to take the time of the 60 second time limit and the second that will be used to keep track of the amount of time the worker R. flavipes did not wander off the track of either the blue pen or blue sharpie squares. The left square is the pen track and the right square is the sharpie track.

Testing of Pen vs Sharpie Test

Open the unused test tube (test tube one) that is filled with R. flavipes workers. Using a thin paint brush, carefully take one of the workers out of the test tube and place it upon either the pen track or the sharpie track. As soon as the termite is placed upon one of the tracks, start the first timer keeping a careful eye on the 60 second time limit. If the termite follows and walks on the pen or sharpie track, start the second timer. But if the termite walks off of the pen or sharpie track, then stop the second timer. Once the first timer hits 60 seconds, that means the trial is over. Record the time that is on the second timer onto an excel spreadsheet. The recorded time will function in keeping track of how long the R. flavipes worker follows and does not wander off of the pen or sharpie square track. The used test tube (test tube two) is now unsealed. Using the thin paint brush place the termite into the test tube. Repeat this procedure a total number of 16 times, making sure there are eight trials using the pen track and eight trials using the sharpie track.

Preparation of Square vs Circle Test

Using an 8.5 X 14 inch white paper, draw one three-inch circle with a blue Bic pen onto the middle of the white paper. This circle will be the test track for the termites to follow. This test will be using the used test tube (test tube two) that is filled with all of the R. flavipes workers that were just used from the previous test (pen vs sharpie test).

Testing of Square vs Circle Test

Open the used test tube (test tube two) that is filled with the previously tested R. flavipes workers. Using a thin paint brush, carefully take one of the workers out of the test tube and place it upon the circle track. As soon as the termite is placed upon the track, start the first timer keeping a careful eye on the 60 second time limit. If the termite follows and walks on the pen track, start the second timer. But if the termite walks off of the pen track, then stop the second timer. Once the first timer hits 60 seconds, that means the trial is over. Record the time that is on the second timer onto the excel spreadsheet. This time will function in keeping track of how long the termite follows and does not wander off of the circle track. The unused test tube (test tube one) is now unsealed. Using the thin paint brush, place the R. flavipes worker into the test tube. Repeat this procedure a total number of eight times.

Results

R. flavipes on Pen vs Sharpie Tracks: After testing the trail following patterns of R. flavipes workers against a pen and a sharpie square track, the data that was collected individually as well as a class was statistically analyzed. The maximum time of the workers on the pen track was 23.42 seconds, while the minimum time of the workers on this track was 9.07 seconds. The maximum time of the workers that stayed on the sharpie track was 10.28 seconds, while the minimum time of the workers that stayed on this track was 0.00 seconds. When a two-sample t-test between the pen and sharpie tracks based on the collected individual times was completed, the calculated p-value against the level of significance was (0.000350812 < 0.05). Within the class data, the maximum time of the workers that did not wander off the pen track was 52.15 seconds, while the minimum time of the workers on this track was 0.00 seconds. Within the class data, the maximum time of the workers that stayed on the sharpie track was 10.28 seconds, while the minimum time of the workers on the sharpie track was 0.00 seconds. When a two-sample t-test between the pen and sharpie tracks based on the class times was completed, the calculated p-value against the level of significance was (1.48242 x 10-14 < 0.05).

Discussion

Within this study, Reticulitermes flavipes workers trail following patterns were examined as the amount of time that the workers did not wander off the various tracks was collected. While the study was conducted, we tested the trail following behaviors of the workers upon the pen against the sharpie tracks and the circle against the square tracks. Because pens contain a common 2-phenoxyethanol chemical that is found within R. flaivpes excreted trail pheromones, it was predicted that the pen and the circle tracks would influence the trail following behavior of the workers as they were compelled to stay on these tracks for a longer period of time. The statistically analyzed results establishes support to pens having an influence upon the R. flavipes workers trail following behaviors. From both the individual and class data, the mean and maximum times were recognized to be greater on the pen track than the sharpie track. Also, the individual and class two-sample t-test supports that pens influence the trail following behaviors of R. flavipes. From the p-value being less than the level of significance and the calculated t-value being larger than the critical t-value, it was indicated that there was significant difference made between the pen and sharpie tracks, therefore establishing further support that the pen has an impact upon R. flavipes worker trail following behavior.

On the other hand, the statistically analyzed results rejects the idea that the circle track impacts the workers trail following behaviors. From both the individual and class data, the mean times was recognized to be a bit greater on the circle track than on the square track. While the maximum times was seen to be in close range within the circle and square tracks. Between the individual and class data, the two-sample t-tests was noted as conflicting. From the p-value being less than the level of significance and the calculated t-value being greater than the critical t-value in the class data, it was indicated that there was a significant difference made between the circle and square tracks. In distinction to the p-value being greater than the level of significance and the calculated t-value being less than the critical t-value in the individual data, it was indicated that there no significant difference made between the circle and square tracks. Therefore, establishing conflicting results that are understood to reject the circle tracks impact upon R. flavipes workers trail following behavior.

Considering the common chemical that is found within R. flavipes excreted trail pheromones and the pens, the results that were obtained as well as the conclusions drawn from testing the pen track against the sharpie track was not very surprising. Other researchers have conducted similar experiments that further examine the 2-phenoxyethanol chemical found within the trail pheromones of R. flavipes. An example of one of these studies includes Chen et al (1998) isolation and transcription of the 2-phenoxyethanol of Coptotermes formosanus, Shikari, and Reticulitermes species. It was interesting to learn that the circle tracks did not impact the R. flavipes trail following behavior because when observing the workers upon the circle track it seemed that they did not wander off of the track as much as they did when they were on the square track. It would be interesting to further investigate the tunneling habits of the R. flavipes workers to learn more about the shapes of tunnels and the influences it might have upon their trail following behavior.

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