Figure 5.

(a) Proportion of live sperm (±s.e.m.) taken from the spermathecae of 10 queens after exposure to Hayes saline. The queens are grouped in four different age classes. (b) Sperm robustness assay with live sperm cells staining green and dead sperm cells red. (c) Number of sperm (±s.e.m.) found in the spermathecae of the same 10 queens. The light grey background circles represent the equivalent data for each of the 10 000 runs of the heuristic model. (d) Mean sperm use during egg fertilization plotted against the number of sperm present in the spermatheca of the same 10 queens. The light grey background circles represent the equivalent output of the heuristic model.