Figure 8. Analysis of the effects of population density on wing fluorescence using the syt-GFP construct.

Fluorescence in adult Drosophila wings was analyzed in 2 day old female flies. Two groups of animals (both males and females) from the same larval conditions were kept at a high density (100 individuals in 20 ml air volume) and low density (10 flies in 200 ml air volume) after their emergence. At this stage, fluorescence shows stochastic variation. Fluorescence intensities equal to or above the levels shown in the photograph were determined from a total of 100 females for each experiment. The values shown are the mean +/−SE (n = 3). The same experiment was carried out with high density larvae (100 in 5 ml food volume) versus low density larvae (10 in 5 ml food volume). In this case the population densities of the adults were kept identical (100 in 200 ml volume) and the values are the mean +/−SE (n = 3) (* p<0.01, **p<0.001,Student test). Two day old flies (females) from three generations reared in high density or low density conditions were also analyzed over the full range of fluorescence (determined as 5 categories). Values are the mean +/−SE (n = 5 and *p<0.01). The five categories were analyzed in the context of contingency tables: Chi square value 12.0296 for a Prob =  0.0171 and DF: 4 (Fisher's exact test: table probability (P) 1.914E-06 and Pr< = P 0.0172).