The use of beeswax as an alkane-bearing marker allows the alkane procedure to be used for the simultaneous
estimation of total and supplement intake, in a situation where the supplement itself does not contain
alkanes. The proportion of supplement in the diet was accurately estimated, using the non-negative leastsquares
procedure in the EatWhat programme. Since total intakes were accurately estimated using either the
C31/C32 or C32/C33 alkane pairs, the product of these and the supplement proportion in the diet of
individual animals resulted in accurate estimates of supplement intake, over a four-fold range of supplement
intakes. The absence of any benefit from adding C28 alkane to the beeswax suggests that beeswax on its own
would be a useful marker, and it has the added advantages of being cheap (approximately $5/kg) and easily
applied to supplements. By contrast, the high cost and poor performance of C38 alkane suggest it offers no
advantage over beeswax.