The proportion of parasitized larvae encapsulating the parasitoid wasp L. boulardi over six generations of selection.

Three species of the D. melanogaster sub-group were selected for resistance over six generations and the encapsulation rate measured. Solid lines represent selected populations, while dotted lines represent control populations. Points are means of 6 replicate populations of D. melanogaster and D. simulans, and 3 replicate populations of D. mauritiana. Approximately 20 vials of flies were assayed per replicate population. Encapsulation rates were estimated using Eq 2 and the bars are equal to ±1 standard error (SE). The SE was calculated from the between replicate population variance for each species. This was impossible for the source population and so instead the mean’s bootstrap standard error is shown. ‘Source’ is the encapsulation rate of the population from which each set of the selection populations was founded, while generation one is the encapsulation rate following one generation of selection. Note that the assays on different species were carried out at different times; as such, precise comparisons between species should be interpreted with care.