Drosophila Effects on Yeast Communities Figure 3. Proportion of banana pieces containing each of the observed yeast species by treatment group. Bananas exposed to larvae alone or to virgin adult females and larvae typically developed yeast communities composed of three species: Pichia kluyveri, Candida californica and C. zemplinina. doi:10.1371/journal.pone.0042238.g003 3. ‘Transplantation’ of Yeasts within Substrates via Larval Fecal Pools Another way that larvae might have affected yeast densities and species composition was by ‘transplanting’ otherwise sessile yeast cells around their natal substrate. We discovered that one day old larvae collected from fly-conditioned bananas left fecal pools behind them that were, 12 h later, filled with yeast colonies, with indications that fecal pool size might be related to food quality (Appendix S2), and that the yeasts in the fecal pools left by one larvae were palatable to other larvae (see Methods, 6). One day old larvae previously fed on conditioned banana deposited 10.26 21.29 fecal pools per hour on RCBA plates, each of which was nearly as long as their 1 mm body length (0.736 20.06 mm). In addition, larvae smeared yeast cells from these pools behind them, leaving an average of 7.176 20.61 CFUs per mm of pathway (Figure 7). Since D. melanogaster larvae travel faster and farther in areas that lack food than in areas with palatable yeast [26], yeast transport via fecal pool deposits by young larvae may help disperse palatable yeasts throughout their natal substrates. PLoS ONE | www.plosone.org 6 July 2012 | Volume 7 | Issue 7 | e42238