Ingredients of sap from oak trees
In Japan even kids know rhinoceros beetles and stag beetles feed on sap from oak trees. Although the importance of the sap for the insects is well-known, it is not famous what does the sap consist of. Some people were aware that the sap contained not only sugar but protein (please see another post). However, I could not find a literature that listed ingredients of the sap. The ingredients were reported in a book Recently I found what I was looking for. The book…