Flies decrease the level of aggression as the availability of food resource increases.

<p>(a) The relationship between aggression (y-axis) and the amount of food (x-axis). Aggression initially increases from 0 mm² to 707 mm² and decreases as the size of food increases further. In particular, aggression observed with the largest size tested 2376 mm² is significantly lower than 707 mm² after correcting for multiple comparisons. Some of the data are the same as those used <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105626#pone-0105626-g002" target="_blank">Figure 2</a> and are replotted here for comparison purposes. n>28 male-male pairs for each condition tested. Pairs are further analyzed for Figures 3b and 3c. (b) Aggression normalized by locomotion shows the same initial increase and subsequent decrease (See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105626#pone.0105626.s011" target="_blank">Table S3</a> for pair-wise comparison statistics). (c) Male-male courtship normalized by locomotion shows no increase or decrease (See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105626#pone.0105626.s012" target="_blank">Table S4</a> for statistics). (d) The decrease in aggression seen in the largest food patch tested (left, 2376 mm²) can be reversed by decreasing the concentration of food to 30% (middle). Calorically, this condition is equivalent to 707 mm² food patch with 100% concentration of food (right) and the amount of aggression is indistinguishable. The 707 mm² food patch data replotted for comparison purposes. n = 32, 31, 86 male-male pairs from left to right. (e) The increase in aggression by dilution of food is significant after normalization for locomotion. n = 32, 31. (f) There is no change in courtship caused by the dilution of food. n = 32, 31.