Sterols of phytophagous and omnivorous species of Hymenoptera

The sterols of six species of Hymenoptera including two phytophagous species (Apis mellifera and Megachile rotundata) and four omnivorous species (Dolichovespula maculata, Vespula maculifrons, Formica exsectoides, and Solenopsis invicta) were isolated and identified. The two phytophagous species of bees have in common relatively high levels of 24-methylenecholesterol and very low levels of cholesterol (<1% of total sterols). The isofucosterol content (40.7%) of M. rotundata was nearly three times that of A. mellifera, but overall utilization of dietary sterols in the two species is similar in that neither is able to convert C₂₈ and C₂₉ phytosterols to cholesterol. All four omnivorous species are predatory to some extent, and the fact that their usual dietary sterols include high levels of chlosterol is reflected in the sterols isolated from these species, which contain 45–81% cholesterol. All six hymenopteran species appear to utilize dietary sterols for structural needs with little or no metabolic modification of the steroid structure.