Drafts

As a first semester junior, Biology 551 was my first upper level course in my college career, prior to this course I only took mainly introductory level courses so this was one of the first challenges I had with taking this course. This class posed mainly challenges for me because it was also one of the first classes I took at UMass that was heavily based on teamwork and outside research projects. My previous two years were filled with lecture and exam style classes where I was not reliable for contributing to a group and most projects were small and individual. Animal communication improved my abilities to work with a group effectively and forced me to take a stronger hold on my education because I learned that I had to do a lot more outside class work in order to succeed in this class. This class improved my academic abilities, professional abilities, and sparked a stronger interest in the science of animal communication and the function of signals and interactions between animals within a species. It has also improved my abilities to think about how to carry out a research project in terms of thinking of a question and coming up with hypotheses and potential answers, and then a research method to effectively find an answer to the question.

The purpose of the experiment was to determine whether different variables of LED light affected spider behavior and web production. We set up six different enclosed environments: two with two different colored LEDs (red & yellow), two with the LEDs in different locations (top & bottom), and two with the LEDs turned off.  We put one cellar spider and two wooden sticks in each container, and left them in complete darkness under a cardboard box for three days. We measured the distance of the cellar spider from the LED in centimeters, and whether or not there was a web present, then analyzed this data. We observed that the LED light had no effect on web formation, as all of the spiders build their webs with one end attached to the LED bulb. However, the LED light did have an effect on spider behavior, as spiders exposed to LED light remained farther away from the bulb compared to spiders not exposed to light.

Our project involves measuring the width of spiders, along with their weight to determine a possible relationship. We accomplished this by using an advanced microscope and individual spider silk. Silk was obtained from the spiders. The spiders were all in the same environment to ensure the variables were the same. Our results showed a negative trend in the relationship, with the heaviest spiders having the thinnest silk. This could be a potential sampling error, and increasing the sample size would offset this. 

The aim of this study was to determine if there is a relationship present between the body weight of spiders and silk thickness, as well as to determine the relationship between weight and thickness among various species of spiders (Pholcus phalangioides, Araneus diadematus, Nephila edulis, Latrodectus mactans, and Euprosthenops sp). We hypothesized that spider silk thickness would increase with the weight of a spider.

Exploring the various factors that contribute to differences in spider web characteristics, such as thickness, could help us learn more about the factors that contribute to their high elasticity and can be useful for the material engineering of a material that is both strong and soft. The diameter of the web is important because it provides some clue as to what the spider uses the web for. There is some variation in spider silk diameters, as well as the mechanical characterization of silk (Blackledge et. al. 2005).

In this study, three spiders were weighed at the beginning of the experiment and they spun webs for 3 days after being weighed to allow for the production of a sufficient amount of silk. After the third day, the thickness of an individual strand of silk from each web was measured using a microscope and micrometre. The measurements of weight and silk thickness were compared to data retrieved from another study (Shao, Z. Vollrath, F. 1999), in which the same variables were measured under similar conditions to determine if a relationship existed between weight and silk thickness.

The conclusions reached as a result of this experiment is that there is a negative relationship in the spider weight-silk diameter of Pholcus phalangioides. However, out data has a wide range of data and may not be conclusive. According to measurement results retrieved from another article for (Araneus diadematus, Nephila edulis, Latrodectus mactans, and Euprosthenops sp), these spiders do not have a clear pattern between weight and silk thickness. This suggests that there is no correlation between the weight of a spider and the thickness of the silk.

• Elevator speech: Our experiment researched whether or not a relationship existed between the weight of cellar spiders and the thickness of the web they produced. We weighed three spiders and were able to collect web from their containers. We took images of the webs using a nikon inverted microscope and then took the measurements of the thickness using a software called “Fiji”. Our data displayed a negative trend, however, other similar studies done show no relationship between the weight and thickness of spiders of different species. To improve our research and to find better data it would be beneficial to take measurements from more spiders of a wider range of weight and find a way to be more consistent in measuring the silk thickness.

This species has developed a series of adaptations for navigating underwater during short periods of time. Its nostrils and reduced ears close underwater, and due to having its eyes protected by a full nictating membrane it mostly relies on its highly sensitive long whiskers for detecting its prey or other obstacles. Nonetheless, this species has good vision on land and uses it for detecting potential prey instead of echolocation, which has been lost in favor of smaller ears that provide better streamlining.

This species has developed certain adaptations that allow it to succesfully enter the water at a high speed when diving. Its unusual beak-shaped mouth provides streamlining, which minimizes the impact against the surface and increases the chances of a successful hunt by avoiding excessive splashing that may scare away fish. Unlike most mammals, which have seven cervical vertebrae, this species has five cervical vertebrae and they are surrounded by thick layers of soft tissue. This gives the bat a shorter neck with a shock absorbing mechanism that greatly reduces the risk of injury when penetrating the water.

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.

Crab spiders are ambush hunters that prey on pollinator insects by lurking in the flowers they visit. Due to the nature of their hunting strategies, we hypothesized that crab spiders prefer to hide in flowers that more closely resemble their body coloration. In order to test this, we set up an arena divided into two colors and recorded the location of the spider prior to being displaced and after being moved to the center of the stage.
The data for the cyan versus green trials suggests that Mecaphesa celer shows an initial preference towards cyan, but when placed in the center of the arena it will move towards the green background. Meanwhile, in the white and yellow trials Mecaphesa initially shows no particular preference between the backgrounds, but when placed in the center of the arena it will move towards the white side. The results agree with our hypothesis that crab spiders prefer backgrounds that match their current body coloration, although further trials with a larger sample size and a refined protocol should be performed in the future to confirm these findings. Despite being a pilot study, this line of investigation could shed light on multiple aspects of the ecology and evolution of cryptic coloration in predator-prey relationships.

Geckos are able to adhere to surfaces thanks to a combination of their physical structures and behaviors. The fingertips of a gecko's hand are made up of lamellae, which are modified scales that contain special hairs called setae. These hairs are tiny, which allow for making better contact with surfaces via Van der Waals forces. As well, geckos have tendons in their hands that allow them to "peel off" their fingers when climbing, and their motions follow a complex set of behaviors that maximize their grip to surfaces.