items, negative electivities indicating avoided items, and zero values
indicating items that are not selected. To summarize the information
gathered by this index, the experimental rearing was arbitrarily
divided in three parts, corresponding to those used for the computations
of SGR (3–14, 14–23 and 23–35 dph, respectively), and the mean
value of Ivlev's index was computed for each food item and for each
part.