The aim of this experiment was to test the effects of temperature on spider web production for the species Pholcus phalangioides. We had hypothesized that the warmer the temperature a spider occupied, the denser the web it would create. During this experiment, spiders were placed in 3 environments set at different temperatures. The control enclosure was kept at 19℃, the warm enclosure was kept at 26℃, and a cool enclosure was kept at 11℃. For the control and cool conditions, the spiders were placed in a plastic cup which was enclosed in a Styrofoam box; the cool condition had a layer of ice underneath the plastic cup with a cardboard barrier to achieve the cool temperature. The spiders in the heated condition were kept in plastic cups that were placed under a heat lamp. Two spiders for each condition were observed for four days; the spider web enclosures were weighed on the final day in order to measure spider web production. Following the data collection and analysis, the results indicated denser web production in the warm enclosure compared to cool and control conditions.
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The social structure of killer whales is very distinct. When focusing on resident killer whales specifically, it is important to note that the basic social unit is called a matriline. This is a group of killer whales which are connected by maternal descent. This core group is highly stable with bonds that are extremely strong. Individuals are rarely seen apart for more than a few hours. Studies conducted have shown that individuals have not been seen to permanently leave any of these observed resident matrilines. Matrilines may consist from 1 to 4 generations of related whales. Pods are the next social structure - which consist of related matrilines that travel and hunt together. Pods are less stable and it is not unusual that a matriline will break away from the pod for an extended period of time. Beyonds pods, are clans. Clans are made up of pods with similar vocal dialects, and may be related. Pods may have developed from one ancestral pod which fragmented over time. Pods from different clans are frequently seen traveling together. The last social level is a community. Whales do not share common maternal links or vocal similarities, but simply share a geographic range.
Similar to resident killer whales, the matriline is basic social unit in transient whales. However they are typically smaller in size, and juvenile and adult offspring can disperse for long periods of time or even permanently. Consistency in grouping patterns is not common. Associations are more dynamic in transient killer whales as well.
Temperature affects many physiological and biological processes in the body. Spiders are ectothermic organisms, so they are unable to regulate their body temperatures relative to their environment. As a result, changes in temperature can have a large impact on their metabolic rate and overall activity. Our project focuses on the effect of temperature on web production in P. phalangioides. To study this, we created three different environments with varying temperatures for spiders to live in and create webs. We had a cool environment that averaged at 11.6 degrees celsius, warm environment at 26.2 degrees celsius, and a control environment at 19.4 degrees celsius. We put three spiders, each in their own cup, in each environment and allowed them to produce webs for five days. We then compared the final weights of the webs in the different environments. It was concluded that spiders in cooler environments typically yielded lighter webs than spiders in warmer environments.
Adaptive radiation is an evolutionary process that explains how organisms can rapidly evolve and diversify from one common ancestor into many different species. This is especially effective when the environment changes and creates new niche spaces for the once common ancestor to fill. The change in environment could be a physical boundary between the common ancestor group that separates them to change, but it could also be the introduction of a different food supply or new predator species. These forces act on the common ancestor and it fills different niche spaces and as they adapt to fill these new spaces, they also diversify enough to be different species. A well-known example of adaptive radiation is in Darwin’s finches. Although they present as different species on the outset, it is possible to trace them back to the same common ancestor. Their evolution occurred over a short period of time and their evolutionary adaptative difference can be explained by the island that the finches inhabit. Once the common ancestor was spread to the different islands of the Galapagos, different environmental pressures presented themselves, such as different food sources which would change the beak shape of the birds.
Like other crab spiders, Mecaphesa celer is an ambush hunter and it preys on pollinator insects by lurking in the flowers they visit. We hypothesized that in order to successfully capture its prey, Mecaphesa would choose to hide in flowers that more closely resemble its actual body coloration. In order to test our hypothesis, we designed an arena split into two different colors based in the RGB color model, and recorded to which side the spider moved after being placed in the center.
We chose to test the colors white versus yellow and cyan versus green in our experiment. Some species of crab spiders are able to change their color from white to yellow, and yellow to white. We decided to use white and yellow as a control in our experiment and see which side the spiders would prefer. The color white is made up of red, green and blue all at their highest intensities which is 255 in the RGB color model. Yellow is made up of red and green both at their highest intensities of 255, with no blue is added. The next set-up contained cyan and green. Cyan is made up of green and blue both at their highest intensities of 255, and no addition of red. Green is made up of only green at its highest intensity of 255.
The results of our experiment testing whether or not a relationship exists between the body weight and the average web thickness of a spider indicated a negative correlation, but likely were unreflective of reality. We hypothesized that spider body weight would be positively correlated with web thickness, speculating that a heavier spider would need a thicker web to support its weight. Before we began our experiment, we found another study that investigated this same subject and found that there was no correlation. We wanted to see if our results would be the same, or if they would be different. We photographed 3 spider webs under a microscope, and for each spider we measured and averaged 10 different threads of its web, then compared them to its body weight. The spider with the lowest weight (Spider 1) had the highest average web thickness, whereas the spider with the highest weight (Spider 3) had the lowest average web thickness. Both measurements of weight and average web thickness of Spider 2 were in between Spiders 1 and 3. However, our results are unlikely to be representative of reality for two main reasons. First, our sample size was very small since only 3 of the spiders we selected for our study produced webs in the experiment time. A small sample size leaves the differences between the measurements up to chance. Second, there was a high standard deviation within each spiders ten individual web strand width measurements; they varied greatly from the “average.” Thus, the average, which was used to identify the trend of negative correlation, is unreflective of the full data scope and thus not a meaningful measurement when plotted against spider body weight. To further this point, one can see in our graph that Spider 2 had a web width average that was in between the averages of spiders 1 and 3. However, looking at all of the individual web strand measurements of Spider 2 that went into the average, one of it’s values is the highest value of all 3 spiders, and another one of it’s values is the lowest of all 3 spiders. It is the spider with the most moderate weight, but it has the largest range of web widths. Since the measurements based on Spider 3 are from the same spider, they are all have the same weight, yet their width varies so largely, so it must be highly influenced by some other factor external to weight. In conclusion after reanalyzing the data, it is unlikely that spider weight has an effect of spider web thickness.
After collecting the data over a two-day time period. Record on an Excel sheet and compare to other projects. The excel sheet should include the distance(in cm) of the spider from the LED light (in the x,y,and z dimension), and the diameter of the web, if present at all. This will be recorded with a ruler from outside the container. Pictures of the spider best depicting its distance from the LED can be taken for reference. Determine whether the light, time exposure, length, color, brightness, or species of spider had any effect on presence of webs in the chamber. This is done by comparing each project results to one another and deciding whether the web that was produced was influenced by the light that was exposed to the spider. If the spider was attracted to the light, then the distance of the web from the light should be smaller than if the spider was not attracted to the web.
Our research could be further improved by developing a more standard method of silk measurements. Within each cluster of silk we obtained from the three webs, there were multiple individual strands of various thicknesses. Different strands of silk could represent different types of silk, such as silk used for web production to catch food or silk that is made as a byproduct of spider function. Identifying different types of web produced by the spiders and only quantifying the same type of web would potentially give more solid data that would better indicate if a correlation between weight and silk thickness existed. We also had to move the spiders around to different locations because we had to bring them to the lab in order to use a scale and the microscope. This means the spiders may have been in states of distress that could cause disruptions in silk production. To better future research, keeping the spiders in the same location throughout the experiment might yield better results because the spiders would be in a constant controlled environment.
If we were to continue research, we could take web samples from more than just three spiders and standardize the measurements.
Several different studies described spider webs as depending upon the mechanical performance of capture threads, and states that web function arises from the architecture and mechanical performance of silk (2). This study also used microscopy, and measured the web thickness of different web types: orb webs, funnel webs, dome webs, and irregular mesh webs. The different types of webs yielded different thicknesses on average, with orb webs being the thickest. Since spider webs must be strong enough to withstand the weight of the spider on the web, and be durable enough to support the spider’s movement, it is plausible that spider weight could also be a factor in web thickness, in addition to web type.