Cockroaches free essay sample

Undergoing this procedure includes using a wide-spread range of concentrations which are mostly preformed at log dose intervals. (H. P. Rang, M. M. Dale, J. M. Ritter and R. J. Flower, 2007). Carbamate Propoxur is an insecticide that can inhibit the action of cholinesterase and disrupt nervous system function (Extension Toxicology network, Pesticide Information Profiles; http://extoxnet. orst. edu/pips/propoxur. htm). In this experiment propoxur was used to investigate the effects on the American cockroach nymphs. The LD50 for one species is very different from another. In each LD50 test there is considerations that need to be understood such as age, weight, sex, health and diet (David Rall, Ph. D. , former Director, National Toxicology Program â€Å"Inadequacy of the LD50 test† Found at http://www. pcrm. org/resch/anexp/LD50. htm). Each individual factor cannot be accurately monitored for each individual animal if randomly acquired. This is only one of the reasons why the LD50 test is not quite useful as it does not maintain a biological constant and that value therefore has little significance in testing toxicity. Methodology Refer to practical manual; however note change in purity of propoxur to 99. 5% hence 0. 2513g was used and also the use of 12 cups of 5 cockroaches making total number of nymphs used 60 Results Table 1. 1 This table shows the procedure used in order to create the suitable diluted solutions needed (Not including the EMK control) | | Starting solution| | Volume of diluents| Tube| Dilution required| Concentration| Vol. (mL)| Vol. | 1| 0. 005%| 0. 01%| 1 mL| 1 mL| 2| 0. 01%| 0. 1%| 1 mL| 9 mL| 3| 0. 02%| 0. 1%| 0. 25 mL| 1 mL| 4| 0. 05%| 0. 1%| 1 mL| 1 mL| | 0. 1%| 1. 0%| 1 mL| 9 mL| As you can see each tube has different means of measures weather it was in volume, concentration or the dilution percentage. This was done in order to achieve a variety of concentrations in calculating the LD50. Table 1. 2 This table shows the average weight of cockroaches in each group Group Name| Average Weight of Cockroaches (g)| Group Anything| 0. 534| JAAMNL| 0. 484| #2| 0. 515| TA| value not provided| SEX| 0. 583| Ebony| 0. 590| Class Average | 0. 521 (includes unknown value for TA)| As you can see from table 1. there were different results when weighing out the cockroaches as you can see the range of the results was 0. 106g. Table 1. 3 This table shows the LD50 determination results of individual group. Cockroaches dead| Control| 0. 005%| 0. 01%| 0. 02%| 0. 05%| 0. 1%| Cup 1| 0| 1| 1| 2| 3| 3| Cup 2| 0| 0| 0| 2| 4| 5| Average per cup| 0| 0. 5| 0. 5| 2| 3. 5| 4| Average % per cup| 0%| 10%| 10%| 40%| 70%| 80%| Our group (group anything) showed some reliable results and from this table it is obvious to see that the LD50 lies between 0. 2% and 0. % note the trend as concentration increases so does fatality. Table 1. 4 This table shows the LD50 determination results by class groups | Control| 0. 005%| 0. 01%| 0. 02%| 0. 05%| 0. 1%| Group Anything| 00| 10| 10| 22| 34| 35| JAAMNL| 00| 10| 13| 14| 44| 54| #2| 10| 00| 11| 22| 55| 55| TA| 00| 00| 01| 21| 43| 45| SEX| 00| 10| 21| 22| 33| 55| Ebony| 00| 10| 31| 42| 52| 45| Average| 0. 083| 0. 33| 1. 25| 2. 167| 3. 75| 4. 583| %Average| 1. 67%| 6. 66%| 25%| 43. 3%| 75%| 91. 66%| The class shows similar results to the individual results showing the LD50 lies between 0. 02% and 0 . 5% as this is where most of the deaths start to show with an increase of concentration trend. Figure 1. 1 This graph represents the Logarithmic view of our individual group (group anything) and the class average displaying a slight sigmoidal shape allowing the LD50 to be calculated at 50% (shown in table 1. 5) Figure 1. 2 This probit graph shows more of a linear representation of our individual group and the class average allowing the LD50 to be calculated at 50% (Shown in table 1. 5) Table 1. 5 | Group anything LD50 (mg/kg)| Class average LD50(mg/kg)| Logarithmic graph| 0. 52| 0. 2| Probit graph| 0. 52| 0. 44| PLEASE NOTE; ONLINE SUBMISSION DOES NOT VIEW THE GRAPH’S, THE SUBMITTED COPY DOES HOWEVER SHOW THE GRAPHS THAT WERE CREATED. Discussion Results indicate that it takes approximately 0. 42mg/kg – 0. 52mg/kg of propoxur to reach the LD50 via dermal application of insecticide. The strongest pesticide in industries today with regards to propoxur is 2. 3mg/kg (Ullmann’s Agrochemicals, Volume 1, edited by wiley-VCH, LASTWiley-VCH pages 691-695). This shows that our r esults could be either inaccurate or accurate depending on how this scenario is portrayed. The most powerful propoxur based pesticide may be used for animals other then cockroaches, however because the nymph cockroach was the only animal tested here, it is very hard to determine the complete effectiveness of propoxur. In this situation however it seems that the LD50 did stray from the normal pesticide use slightly, this could have been due because of experimental errors while preparing dilutions or application of the solution. Table 1. 2 shows one of the greatest errors possibly in this experiment. The average weight lies at a range of 0. 06g which speaking on the insect level is quite a significant number here. The method of weighing out the cockroaches was extremely inaccurate and in order to achieve an accurate LD50 an accurate weight is required as stated earlier. Also not all cockroaches were exactly 2cm in length as suggested by the method hence some cockroaches had a higher resistance to propoxur due to greater weight and size which meant consistency was not at all achieved. Another reason why results may have varied from group to group could be due to miscalculations and human error while performing dilutions. Dilutions is a very important part of the experiment and if there was an error in one simple dilution then it could have carried on from tube to tube having detrimental effects on the concentrations of the solution being created. Also application of the solution to the cockroaches was not an easy task, the cockroaches were able to move around and escape from containment prosing an extremely large problem because if the cockroach were to escape and become lost, the entire average weight would have to be changed. Preventing this setback happened to cause another dilemma, to slow down the cockroaches and comatose them freezing was applied. However if the cockroaches were frozen too much they would die and once again the entire weight of one cup of cockroaches would change and the mistakes would carry on. These errors could explain why in table 1. 2 that there was a death in the control for group #2. This experiment was not entirely a success due to these errors. Easily these setbacks could have been avoided by being more aware especially when performing accurate dilutions and controlling the cockroaches. Laboratory conditions may not have been the best scene to conduct this experiment as the cockroaches could escape.