The changes of polyphenols as a result of the passage through the gut of the gypsy moth Lymantria dispar (Lep., Lymantriidae):: influence on the growth of the larvae

The gypsy moth Lymantria ia dispar is known as a 'polyphenol specialist' which is relatively tolerant of the phenolic compounds of its host plants. It is known, however, that the phenolics inhibit the growth of several feeding insects, including the gypsy moth. Attempts to identify how the phenolics work have met with mixed results. Several authors have described how the phenolics undergo alterations during their passage through the gut of the insects. However, whether this does indeed correlate with the growth-inhibiting function or not has not been investigated so far. The present results show that the polyphenols are polymerized during their passage through the gut which results in an increase in phenolics with higher molecular weights. Some of these changes correlate positively with the growth of the larvae which means a detoxification of the original substances takes place. The negative correlation with an increasing amount of the phenolics during passage through the gut seems to be the result of polymerization which may activate the polyphenols to help defend against the feeding insect.