Interspecific Competition Predation

Competition, predation and species responses to environmental change In the study that was run they were trying to examine the effects of interspecific competition which is when individuals of different species are competing for the same resources such as food and shelter in an ecosystem and the preying of one species on another species due to species responses to temperature change (Jiang and Kulczycki, 2004). Other experiments have been run on temperature change but they do not have a good understanding of species interaction when the environment changes. This may be due to the fact that past studies only focused on single specie populations or ecosystems as a whole. From these studies they were able to show that due to temperature changes …show more content…
The Didinium was the predator and preyed on the Colpidium and the Paramecium which are both swimming bacterivores. The 240 ml capped bottles were used as the miniature community features of something much larger known as microcosms. The bottles had two wheat seeds and 100 ml of nutrient medium. The medium was made up of .55 g of protozoan pellet and a liter of well water (Jiang and Kulczycki, 2004). These were autoclaved by being put in a high pressure chamber with high pressure saturated steam. The first things to go into the bottles was the medium and three bacterial species that the Colpidium and Paramecium have as there food resource. The three bacterial species include Serratia marcescens, Bacillus cereus and Bacillus subtilis. After twenty four hours the bacterivores were added into the microcosms, then a week after the Didinium predators were added. The experiments were run with two main factors the temperatures and having a presence or absence of interspecific interactions. There were three different temperature factors were 22, 26, and 30 degrees Celsius that were used in this experiment (Jiang and Kulczycki, 2004). Then the specie interactions had three different sets. The first was the control which was just the one or the other of the bacterivores in the microcosms, the second was both the bacterivores in the microcosms competing for …show more content…
Didinium increased and Colpidium decreased in the predation group but, Colpidium never went extinct. Didinium did not change the response of Colpidium to temperature change. In the competition interaction the Colpidium was in higher abundance then the control, and the Paramecium did not affect the response of Colpidium to the temperature. For Paramecium with the increase in temperature there was an increase in growth rate. It did not affect the density however. In the predation group the Didinium reduced the Paramecium to eventually extinction in all three temperatures (Jiang and Kulczycki, 2004). In the competition interaction group the Paramecium lived with the Colpidium at temps 22 degrees Celsius and 30 degrees Celsius, but went extinct at 26 degrees Celsius. They are unsure of why this occurs though. This means that competition from Colpidium significantly decreases Paramecium abundance and that the competition from Colpidium alters the response of Paramecium to temperature. The experiment should have also included some results for Didinium so that when looking at predations we may better understand the results (Jiang and Kulczycki, 2004). Also this experiment does not account for changes in the temperature affecting the species interaction strengths. I think using ciliates was a good idea for running the experiment since they do not have complex life