Megan Pelletier 9/22/15 Ecology Lab Article Summary: Variation in selection pressures on the goldenrod gall fly and the competitive interactions of its natural enemies This article talks about Eurosta solidaginis which is the goldenrod gall fly and its interactions with its natural enemies. The natural enemies that are discussed in this article are Eurytoma gigantea and the E. obtusiventris which are both different types of parasitoid wasps, Mordellistena unicolor which is a beetle and two predatory birds the Dendrocopus pubescens which is the downy woodpecker and Parus atricapillus the black-capped chickadee (Abrahamson, 1989). These natural enemies eat the larvae of the goldenrod gall fly while in the gall. The galls are found on tall goldenrod plants. The goldenrod fly induce ball-shaped galls on the stems of …show more content…
these plants.
The gall is made of plant tissue but aspects of genetically coded stimulus from the insect makes the gall from the normal plant tissue (Abrahamson, 1989). The gall can be many different sizes in diameter. Survival depends on the gall size, the smaller the galls means that the larvae is vulnerable to parasitoid oviposition, but when the galls are larger they are more likely to be attacked by avian predators (Abrahamson, 1989). Gallmaker enemies can influence the survival of individual gallmakers. The natural enemies of the gallmakers can have a potential effect and alter gallmaker traits for other generations if survivorship varies (Abrahamson, 1989). This study wanted to know three things, how many gallmakers there are as well as how many natural enemies there are, and to what extent of the goldenrod fly mortality was due to insect and bird enemies listed above. They also wanted to know what gall size did these natural enemies prefer and what kind of
selection pressure resulted from the natural enemies attack. Finally they wanted to know at what extent the natural enemies compete for the gallmaker (Abrahamson, 1989). The way they went about this experiment was using the twenty natural old fields in Pennsylvania and placing fifty quadrants across each field at equal distances. They counted all the galls in each quadrant between August and September (Abrahamson, 1989). They then collected a minimum of nighty seven galls from the twenty different fields in Pennsylvania during November to December then again in April. The galls from both seasons were collected and measured to the mm by passing them through stencil circles. Once that was complete they then dissected the galls to determine what was inside of them. When there were beak chisel hole that penetrated the central chamber of the gall it meant that that bird was successful at getting its prey, but if there was evidence of the Mordellistena than it was not counted for the birds success (Abrahamson, 1989). If the birds chisel marks did not reach the inside of the gall that still had Eurosta or a parasitoid then it was considered unsuccessful. Any holes from the E. gigantea, tunnels from the Mordellistena, gallmaker deaths, or any empty galls were also recorder. To find out the percent of mortality that was caused from each of the natural enemies the surviving Eurosta, parasitoids, Mordellistena, and galls successfully attacked by the birds were calculated. They took down the data for both November and April. The November data was used to determine the gallmaker and enemy occurrences before the attack of the birds, while April data was used to compare to November on natural mortality over winter and determine the level of bird attacks (Abrahamson, 1989). To find selection intensities of gall size made by natural enemy attack were calculated by the difference if the mean gall diameter of the selected individual and the mean gall diameter of the entire population then divided by the populations’ standard deviation. This does not include the evolutionary response however (Abrahamson, 1989). The first result they found was on the mortality sources of the galls. What they were able to find from these results were density of the galls and the attack rate of the natural enemies were highly variable from field to field in both the seasons. There were more surviving galls from November then there were from April. November showed a 29.3% survival while April only showed a 23.6% survival percentage for the Eurosta (Abrahamson, 1989). The reason as to why the percentage was higher in November was from the winter exploitation of galls to the birds. In November the percentage of mortality due to the birds were 3% while in April the mortality caused from birds was 15% (Abrahamson, 1989). They were also able to get results on if mortality depended on the gall size. From the study the found that the E. gigantea were restricted to the galls of a particular size range but the rest of the insects were not. The E. gigantea attacked the smaller density galls, while the Mordellistena attack the galls of medium density and E. Obtusiventris and most of the surviving Eurosta had the larger density galls. The bird attack on the galls had no correlation for the diameter of the gall (Abrahamson, 1989). Selection intensities created by Eurosta mortality due to the natural enemies varied from each field. There were very small directional selection intensities in the 254 field due to the upward selection of the E. gigantea being balance out by the downward selection by the birds. This meant that a stabilizing selection dominated this field. The other fields varied from this with some being more upward selection due to not many birds in that field and then for other fields it there was more downward selection due to the great amount of birds in that particular field (Abrahamson, 1989). The net selection due to pressure from the natural enemies resulted in upward selection differential on the mean diameter of the galls that still had living Eurosta in them. Finally they found results on the insects’ natural enemy competition. What they found was that the galls were attacked by more than one of the natural enemy and that they were consuming once another (Abrahamson, 1989). To be able to record the data they took the ultimate survivor of the gall. The most important finding was that there was a net upward selection pressure on the Eurosta gall diameter created by the natural enemies. These numbers do not account for the evolutionary response to those pressures (Abrahamson, 1989). There was an upward intensity due to the amount of E. gigantea, E. obtusiventris, and Mordellistena attacking the smaller galls compared to the birds attacking the larger galls. The amounts of attacks on the small galls were much greater than the amount of attacks to the large gall making the gallmakers have an upward selection pressure on gall size (Abrahamson, 1989). The authors of this journal were able to find the conclusions of their hypothesis and collect all those different parts of the hypothesis with one study. The study seemed to be done accurately by using 20 fields and have 50 quadrants in them. Also the fact that they collected such a large data helps to their case stronger. The calculations that were done to find what they wanted seemed to be accurate
Wise, M. J., Abrahamson, W. G., & Cole, J. A. (2010).The role of nodding stems in the goldenrod–gall–fly interaction: A test of the “ducking” hypothesis. Manuscript submitted for publication, Available from American Journal of Botany. (0900227)Retrieved from http://www.amjbot.org/content/97/3/525.full
The objective of this experiment is to determine what genes are responsible for the white-eye color in two strains of Drosophila melanogaster, known as the common fruit fly. Drosophila is used as the experimental organism for many reasons which include its small size, easy maintenance, short 10 day generation time, and a fully sequenced genome. The characteristics of the wild type, which is the most common phenotype found in nature, include brick red eyes, long wings, gray/tan body, and smooth bristles. Of course, there are mutations that occur that cause specific traits to deviate from the wild-type phenotype. These traits include wing length, bristle shape, body color, and eye color.
Outline the physical similarities between the (Blaptica dubia) cockroach and the cricket. Explain previous studies on physical stress in the cricket and in different species of cockroaches. Briefly discuss how the metabolic rate between the two species has been found to be very similar.
However, evidence such as fossils is more than enough to lend support and disprove any other theory to the development of species. Examples used by Root-Bernstein and McEachron also provide strong support to evolution. The authors detail how natural selection works in both insects and germs to create organisms better adapted to methods of control. Disease used to run rampant, until the creation of vaccines which led to many diseases becoming extinct. Root-Bernstein and McEachron note that the diseases that have survived to this day have been constantly mutating and evolving to become more resistant to any attempts at suppression. The same can be said for insects that have been consistently exposed to pesticides. The ones that survived the pesticides were able to reproduce and pass along a resistance to their offspring which in turn makes the species more resilient and better suited to their
Abstract: The house cricket, Acheta domesticus, was used to test whether food and potential mates drive aggressive behavior. Male crickets were randomly selected in pairs and place into a cage to observe aggressive behaviors in the presence of no food, food, and female. The cage provided a confine area for the crickets to fight one another while the variables of food and female were used in attempts of increasing aggressive interactions between the male crickets. There was no significance found through this experiment due to a lack of data. It was discovered that the experiment would have to be done at a larger scale to be able to see any significance in the two variables.
Richard Conniff uses strong scientific facts in his essay to get his major point across to the audience. One of the major facts he uses stood out as it disproved many a wives tale about the common household fly. Most people think of flies as dirty animals who fed on dead animals and spread disease. Conniff uses a study that found flies tested from dirty areas contained more a lot mor...
Smith, R.H. (1963). Toxicity of pine resin vapors to three species of Dendroctonusvbark beetles. Journal of Economic Entomology 56: 827-831
Pillbugs are also known as terrestrial isopods but non scientific names include sow bugs and woodlice. These terrestrial isopods are in the class of crustaceous, this class includes lobsters and crabs and is part of a larger group named arthropoda. Pillbugs have four pairs of mouthparts, and have multiple flexible joints. Pillbugs also have a flat and rounded back, wide head, 14 legs with 7 pairs all together, and they have the ability to roll into a ball when in danger. Pillbugs have 7 main “trunks”and have multiple overlain gills which allow the insect breathe. The diet of a pillbug consists of dead or decaying plant or animals, and pillbugs are both scavengers and omnivores. Due to their gills pillbugs live in areas with high humidity such as under fallen trees, logs, rocks, bushes, and wet leaves. In our hypothesis we state that if the pillbugs are accustomed to breathing water, then they will be drawn to the less sweet liquids.
Females like to choose mates who have very bright colors as it is a sign of the male’s good health and vigor. The natural and sexual selection can affect populations in three ways: directional (environmental conditions change in a consistent direction; one extreme of phenotypes is favored), stabilizing (environmental conditions are relatively constant; intermediate phenotype is favored), and disruptive selection (environment has more than one type of useful resource; both extremes of phenotypes are favored). An example of directional selection is pesticide resistance since only the insects with a resistance are favored; an example of stabilizing selection is that the smallest lizards have a difficulty defending their territory whereas the largest lizards are most likely to be eaten by owls; an example of disruptive selection are the black-bellied seedcrackers since they either have a large beak (which they can use to eat had seeds), or a small beak (which allows them to eat soft seeds). Disruptive selection shows a balanced polymorphism, which is when two or more phenotypes are maintained in a
“Organic Wisdom, or Why Should a Fly Eat Its Mother from Inside.” Ever Since Darwin. New York, New York and London, England: W.W. Norton & Company, 1977.
Some individuals have developed different traits to help them in the process of intra-sexual competition. The organisms with more distinctive traits have greater reproductive success. More genes of those traits are then ‘selected’ and are passed onto the offspring of the organisms. Throughout time variability in these traits becomes
As useful as their tongue is for collecting nectar it is useless in capturing insects hidden inside flowers, even though insects do provide most of the protein...
Dr. May Berenbaum, an entomologist at University of Illinois, has conducted over 40 years of research on parsnips and the parsnip web worm. During her lecture on March 22nd, she explained how parsnips are invasive weeds that are full of toxic furanocoumarins. Interestingly, the parsnip webworm only eats the parsnips and is able to process the toxin very well. The interactions between the web worm and parsnips cause the parsnips to select for plants with a higher amount of furanocoumarins in order to defend themselves from the worms. When the worms are not there, i.e. in New Zealand, the parsnip plants grow taller and develop more ways to attract pollinators, and they do not put energy into having as many furanocoumarins
I decided to palpate the spine of the scapula. I did this because the scapula is more defined in the back making it easier to feel on my partners back. I was able to locate the scapula on the rib cage and also the scapulae surface. I was capable of palpate the indentations at the superior and inferior halves of the bone as well. The easiest place to palpate was the scapula surface. The surface was very visible when my partner extended his arm out to his side. The most challenging to palpate was the indentation because I had to really feel for it. Even with my partner extending his arm out I could barely find it. I had to have my partner put his arm down and extend it back out to find the indentation.
I absolutely loved Stick Fly—my attention was captured during the entire play. There were moments when and I cried and there were other moments when I laughed. The scene was amazing! It looked so realistic, especially the bookshelf and the kitchen cabinets. I could have lived in that house if it was really a house. The set design and the actors’ clothes fit in with the time period. The lighting was great also. There were these window panels hanging around the room and as the scenes changed the lights over the panels caught people’s attention. I would notice people turning around looking at the lights. Also my favorite was the light outside of the kitchen window. Once again, it looked very realistic the light would change as the time of day changed. You were able to notice when it was day, evening, and night due to the light from the kitchen window. Another thing that made the scene so realistic was that the sink actually worked. Overall, the set was amazing!