Behavioral experiments have shown that the principal and secondary eyes work together to precisely target moving stimuli. For example, Dr. Beth Jakob and colleagues investigated how the secondary anterior lateral eyes direct the principal eyes of Phidippus audaxwhen tracking moving objects. Phidippus audaxwere tethered in front of an eye-tracker that recorded the movement of the principal eye retinas. When spiders with their anterior lateral eyes unmasked were shown a moving disk, the principal eye retinas moved close together and were able to track it. Meanwhile, masked spiders were unable to track moving disks with their principal eye retinas. This indicated that principal eyes can precisely target moving stimuli only with the guidance of the secondary eyes (Jakob et al., 2018). Furthermore, Cupiennius salei, a wandering spider from the family Ctenidae, has also been shown to have closely cooperating principal and secondary eyes. Cupiennius saleihave moveable principal eyes that are controlled by four muscles (Kaps, 1996) (Land, 1969). Masking the Cupiennius saleisecondary eyes reduced their principal eye movement (Neuhofer et al., 2009).
All spider families for which data exist have movable principal eyes. However, the size and motility of the principal eyes vary greatly. Jumping spiders can move their retinas in all directions, whereas other families are capable only of very small lateral movements. In addition, the amount of overlap in the field of view between the principal and secondary eyes varies across families. Small principal eyes with a wide range of motion, such as in jumping spiders, depend on information gathered by the secondary eyes to be directed to a target. I predict that these families will invest more in visual pathway neuropils and in the number of optical glomeruli. In families with larger principal eye retinas with wider fields of view and less motility, information from the secondary eyes may be less important. This may lead to less investment in visual pathway neuropils and a decrease in the number of optical glomeruli.
The secondary eye pathway of jumping spiders is complex compared to other spiders (Long 2019). Of interest for me are the optical glomeruli of the secondary eye medulla. Information from the secondary eyes is sent to the lamina, followed by the medulla. From the medulla, nerves project and combine in the mushroom body (Strausfeld et al. 1993). Unlike the mushroom body in insects, it is likely that the mushroom body in spiders is completely given over to vision. In insects, information from the lamina is passed to the medulla via a complete chiasma and this retains a panoramic field of view. In spiders, information from the lamina is chunked in the medulla before being passed to the mushroom body (Strausfeld, 2012). This prevents a panoramic view but may increase the spider's ability to quickly process motion information in discrete regions of the visual field. This may be particularly important for targeting the movement of the principal eyes. Retinotopic information from the lamina is passed to the protocerebrum simultaneously via a separate tract (Strausfeld, 2012).
The visual systems of different spider families can be correlated to their life histories and behaviors. Many diurnal cursorial spiders like salticids have enlarged principal eyes and small secondary eyes with a wide field of view for detecting prey. Nocturnal hunters like wolf spiders (Family Lycosidae) and net-casting spiders (Family Deinopidae) have small principal eyes and enlarged secondary eyes. Meanwhile, some ambush predators like crab spiders (Family Thomisidae) and web-building spiders like long-jawed orb weavers (Family Tetragnathidae) tend to have small, evenly spaced principal and secondary eyes. Furthermore, the visual processing pathway is separate for the principal and secondary eyes. And the principal and secondary eyes each have their own neural pathway within the spider brain (Strausfeld and Barth, 1993).
The number, complexity, and arrangement of spider eyes vary across spider families and often correlate with behavior. In addition, the size and organization of the visual processing regions of the protocerebrum also vary (Long 2019). The structural and functional unit of the nervous system of spiders, like other animals, is a neuron. Additionally, the spider central nervous system is composed of discrete synaptic regions called neuropils and the inside of the neuropil is comprised of nerve fibers and glial components. The central nervous system of spiders is composed of two major regions called the supra-esophageal and sub-esophageal regions (Barth 2002; Strausfeld 2012). The supra-esophageal region is considered to be the brain of the spider and it consists of the protocerebrum and the deutocerebrum. The sub-esophageal region is comprised of tritocerebrum and leg ganglia (Strausfeld 2012). In addition, the sub-esophageal region contains afferents from all sensory systems except the eyes (Barth, 2002; Strausfeld, 2012). Moreover, this is the largest region of the spider central nervous system. For example, in Cupiennius salei, the sub-esophageal region makes up about 85% of the total central nervous system (Barth, 2002). The protocerebrum contains the optical lobes that receive information from the spider’s eyes. Among them, the most important are structures called the central body, proto-cerebral bridge and paired mushroom bodies. All of them receive information from various sensory and motor cells. The input of information into the protocerebrum from the rest of the central nervous system supports the idea that it serves as an integration center (Babu and Barth, 1984).
The study of the nervous system of spiders has long been one of the central problems of natural science. The birth of studying the spider central nervous system is dated back to 1890, the year that the brilliant work of Saint Remy laid its foundations. His work described the central nervous system of the labidognath family of spiders (Remy 1890). Moreover, in the 1920s, Hanström applied the Golgi staining technique to study the spider brain. He noticed that spider visual neuropils varied greatly in size and organization (Hanström 1921). Furthermore, Hanström claimed that the spider brain and insect brain have shared neural structures. This idea of brain homology can still be found in current literature today (Babu 1965, Bullock and Horridge 1965, Firstman 1954, Legendre 1959). In addition, Legendre has given a comprehensive study of the brain morphology and development of spiders (Legendre 1965). However, early 20th century researchers, such as SaintRemy, Hanström, and Legendre were limited by techniques and sample quality (Long 2019).
When you think about football, you think about speed, strength, reaction time, coordination and so much more but do you think about looks? Attractiveness has nothing to do with a players ability to throw, catch or run but a study by the new york times found that “attractiveness” has a positive impact salary stating that attractive players could look forward to an 8 percent increase in pay (“Pretty-Boy Quarterbacks”). Attractiveness matters so much that players like Kerry Collins had salaries that did not reflect their skills but certainly their attractiveness (“Pretty-Boy Quarterbacks”). So how is it that a player who has a higher quarterback rating, higher number of passing yardage (distance they throw the ball over time) and more touchdowns for attempt seems to be paid less than a more attractive athlete if they are objectively deemed better by NFL analyst like Brian Billick who breaks down stats for a living (“Draft a QB”). Through our project we hope to come to a clearer understanding of the effect of attractiveness on salary if any and furthermore if it plays a bigger role than a players skill in areas like QB ratings and touchdowns per attempt. We will do this through comparing a players salary, attractiveness and a handful of skills to see if more attractive players make more money than less attractive players with more skill with all of our data coming from the excel sheet. Whether or not there is a correlation can prove to destroy the misconception that money equates to overall skill. Understanding the relationship between attractiveness and salary can help the managers understand how to make better use of their teams funds. Why use that money on good looking athletes instead of using it on talent to strengthen their teams?
Precipitation is something that most people regularly experience in their day-to-day lives. While most view it as an annoyance or hinderance, life would not be possible without it. Precipitation is a key step in the water cycle and is a direct result of water evaporation. Precipitation can come in different forms, depending on different weather and atmospheric conditions. In a climate that is above the freezing point of water, rain will be the form of precipitation; however, in cold environments such as New England during the winter, snow is very common. As the weight of the water in the clouds becomes too much, water starts to fall to Earth's surface, and with the temperatures at freezing or below, the water becomes ice crystals and falls as snow. If conditions are particularly windy near the clouds, the ice that falls can be blown back up and collect more ice and keep repeating this until it is too heavy to be blown back up, this is hail. Precipitation can be dangerous, but we should never take it for granted.
My name is Mariam Labib, and I am a junior presenting to you the Effect of Air Quality on Lichens in Different Areas of the Forest. I will start off by speaking to you about the background as well as methods. My classmates and I went to a secluded area filled with trees, bushes, etc right behind Orchard Hill Residents Halls. We walked across a road which then led into a forest. We then created a plot which was three meters into the forest. Within this plot, we had put flags around the edge to make sure we respect the guidelines of our project. We then took a 1 meter measuring tape, we started at the bottom of the tree and went up 1 meter. We then split the task, and each person counted how many lichens there were in a 5x5-inch metal grid. We repeated this until the grids filled up the one meter. It is important to note we made sure that we took these measurements on each “north side” of every tree, as per the Lichens Textbook found in Professor Brewer’s office, this is what was noted. We repeated this in the second plot which was 20 meters into the forest. Our hypothesis was that there would be more lichens in an area 20 meters deep into the forest, as it has less disturbances such as gas rising from cars from the road, thus having better quality of life for the lichens to grow and populate. We found that the trees which were 20 meters deep into the forest had more lichens, thus proving our hypothesis. Additionally, our p value was small which indicates it is significant. Overall, it was a very successful project. In the future, I believe there are many modifications that can be done to have a larger difference in our results, but this is a great step forward in the research area of lichens!