Non-independence of individuals in a population of Drosophila melanogaster: effects on spatial distribution and dispersal.

We used a simple quadrat analysis to globally categorise the spatial distribution of Drosophila melanogaster individuals. Individuals were spatially aggregated and this was not only due to sexual attraction. This aggregation seemed to be maintained during dispersal, hence explaining the great variability of this behaviour observed in our work and by other authors. Thus, individuals are expected to arrive as small groups into a new patch. This may induce costs through competition and benefits by ensuring the presence of reproductive mates and/or if there is a phenomenon of local resource enhancement by the presence of conspecifics, hence influencing the evolution of dispersal.