Temporal distribution of C. elegans (top) and C. briggsae (bottom) abundance in Orsay apples along four consecutive years. The graphs show the proportion of apples with a given census size (expressed on a log scale) of C. elegans or C. briggsae populations. The number of apples with a given census size is indicated in each color-coded bar. The two time points labeled by stars (6 and 14 October 2008) were sampled under a single tree (see Additional File 4) and were not used with the others in the statistical analyses. 19 August 2008 was particularly hot (36°C maximum temperature, labeled above the graph). See statistical analyses in the Results.