Alcohol Consumption Drosophila Melanogaster
Alcohol consumption in sexually frustrated fruit flies Drosophila melanogaster Ankit Sharma April 8, 2013 BIO 534 Introduction The fruit flies Drosophila melanogaster show addiction-like behavior towards alcohol where the flies seem to be physiologically dependent on (Atkinson et. al. , 2012). The flies can thus exhibit a cognitive dependence where such behavior is stored in memory and same behavior is also shown in the future. This addiction is linked to NPY neuropeptide levels which can be found in Drosophila where these neuropeptides serve as feeding stimulants (Shen et. al. , 2005).
Alcohol consumption rate is higher when these NPY neuropeptide levels are suppressed (Wilcox, 2012). Thus, such factors are linked to the idea that fruit flies consume food that contains alcohol more than regular food, and such behavior increases over time (Devineni and Heberlein, 2009). Sexual frustration is also linked to increase in consumption of alcohol. Fruit flies consumed less alcohol when they were sexually satisfied because sex raised NPF levels and the flies consumed more alcohol when they were sexually frustrated because their NPF levels were suppressed (Azanchi et. l. , 2012). The purpose of the experiment is to determine if sexually frustrated male fruit flies Drosophila melanogaster resort to alcohol after being rejected by females. Thus, the experiment will determine if the number of sexually frustrated fruit flies will be higher where there is alcohol in the environment than non-sexually frustrated fruit flies. The hypothesis to be tested is null hypothesis. The null hypothesis states that sexual frustration has no effect on alcohol consumption by male fruit flies.
Thus, there will not be a significantly higher number of rejected male fruit flies in an alcohol environment than non-sexually frustrated flies. Materials and Methods Two plastic cylindrical vials were used to place wingless wild type fruit flies. The vials contained same amount of medium for food. Both vials contained regular medium for food. The fruit flies were anesthesized and 40 males and 40 females were separated. 20 males were placed in a vial with 20 females that were decapitated by a razor blade. 20 separate males were placed in a different vial with 20 females.
The experiment was conducted over a period of 4 days. Two more vials were made, both containing 21% alcohol on one half side of the medium which was the closest percentage available compared to 15% ethanol used in other experiments. The males with decapitated females were transferred to one of the vials with alcohol. The males with regular females were transferred to the other vial with alcohol. The number of flies present on alcohol and normal side of the medium was recorded in both vials for 20 minutes in 1 minute increments. Three trials were conducted.
The mean numbers of fruit flies present on the two sides of both vials were calculated. The mean was calculated by the summation of the number of fruit flies in each sides of the vials and divided by 120. The null hypothesis was tested by conducting a two-tailed t-test. Results For all the number of fruit flies observed in the two vials (n=120) there was a significant difference in the number of fruit flies in the two vials in the (t=4. 87, df=118, p<0. 0001). The difference in the mean number of flies present of the alcohol side of both vials containing decapitated and normal females was significant.
The number of flies present on the alcohol side of the vial containing decapitated females was about less than 50% higher than the vial with regular females significantly (Figure 1. ) Discussion The null hypothesis is rejected. The t-test results show that there is a significant difference in the mean number of fruit flies in the two vials (p<0. 0001). Thus, there is a significant relationship between sexual frustration and alcohol consumption. The null hypothesis states that sexual frustration has no effect on alcohol consumption in male flies.
Since there is an effect of sexual frustration on alcohol consumption in male flies, the null hypothesis of no effect of sexual frustration on alcohol consumption is rejected. The results from Azanchi et. al. (2012) show a significant difference (p<0. 01) in alcohol consumption in males with decapitated females and regular females. Thus, there is an effect of sexual frustration on alcohol consumption. Since there is an effect of sexual frustration, therefore this rejects our null hypothesis of no effect of sexual frustration on alcohol consumption.
A difference between the number of sexually frustrated males on alcohol environment more than non-sexually frustrated males was observed and the difference was statistically significant. The results from Azanchi et al. (2012) also reject the null hypothesis. The experiment was conducted for a longer period of time where measurement of amount of alcohol consumed was measured instead of number of flies. These may have accounted for an experimental design that could lead to better results since sexually frustrated fruit flies were observed to exhibit higher preference for alcohol. Literature Cited Atkinson, N. S. , S.
Khurana, A. Kuperman, B. Robinson. 2012. Neural Adaptation Leads to Cognitive Dependence. Current Biol. 22, 2338-2341. Azanchi, R. U. Heberlein, H. Mohammed, G. Shohat-Phir. 2012. Sexual Deprivation Increases Ethanol Intake in Drosophila. Science. 335, 1351-1355 Devineni, A. V. , Heberlein, U. 2009. Preferential Ethanol Consumption in Drosophila Models Features of Addiction. Curr. Biol. 2126-2132. Shen, P. , Q. Wu, J. Xu, Y. Zhang. 2005. Regulation of hunger-driven behaviors by neural ribosomal S6 kinase in Drosophila. PNAS. 102, 13289-13294. Wilcox, C. 2012. Sexually deprived Drosophila become bar flies. Scientific American.
