Population cages and larval development of two mitotypes.

(A) Flies with Alstonville or Dahomey mtDNA were competed (n = 3 cages). Initially, the diet had a 1:2 P:C ratio. After four generations, the diet was switched to 1:16 P:C. An incubator malfunction killed all Drosophila in generation 16, so cages were re-established with a similar frequency of each mitotype. In generation 20, the diet was swapped back to 1:2 P:C. Plotted data are mean± s.e.m. mitotype/generation/cage/diet from ~80 flies/cage. (B) The number of females eclosing in 3 d was determined. The control was flies with w1118 nuclear background fed 1:2 P:C and 1:16 P:C laboratory diets (n = 29 replicates of ~80 flies/rep for the 1:2 P:C diet, and n = 48 replicates of ~80 flies/rep for the 1:16 P:C diet). First, the nuclear genetic background was replaced with Oregon R (n = 6 biological rep/mitotype/diet). Second, the nuclear genetic background was replaced with Canton S (n = 5 biological rep/mitotype/diet). Third, passionfruit and banana replaced the laboratory diets (w1118 nuclear background, P:C ratio of ~1:2 P:C and ~1:16 P:C, respectively; n = 5 rep/mitotype/diet). Finally, the microbiome obtained from wild-caught flies was introduced (w1118 nuclear background, n = 6 biological rep/mitotype/diet). The 3 d eclosion window began on day 14 for 1:2 P:C diet and day 28 d for 1:16 P:C diet. Plotted data are mean± s.e.m. * p< 0.05, ** p< 0.01, *** p< 0.001 as calculated by t-tests (see text).