Ambrosia Maple is a general term attached to a variety of Acer (true maple) species whose boards included colorful bug "trails" -- caused by a fungus carried by the Ambrosia Beetle which penetrates the tree sap as the beetle eats into the tree, and it spreads both through the worm hole and up and down in the tree (carried along by the sap) and causes discoloring of the wood in streaks. The two primary species which draw the beetle's attention are Acer rubrum (Red Maple) and Acer saccharum (Sugar Maple), although -- with there reputedly being more than sixty different Acer species indigenous to North America -- this unusual phenomenon is certainly not confined to just the two. Weight and density can vary greatly -- depending upon the actual species -- the typical varieties of maple figuring can also be present, often creating some very unique, visually spectacular specimens.
Like any other maple, it is easily worked; generally cooperative through all phases. It's not much of a stretch to imagine -- since bugs have, quite obviously, already penetrated the wood's surface -- that the wood is decidedly non-durable, although it is generally stable enough for use in furniture and guitars. Its surface is typically darker than most sap maple (often featuring secondary / additional discolorations and other long streaks), although it retains the same high degree of natural luster.
The scientific explanation is that the impregnated Ambrosia Beetle burrows into the maple tree (presumably for a safe place to deposit larvae), carrying fungi on its feet into the wood -- which serves as food for the insect's offspring, when they hatch. The fungal residue left behind as it digs into the maple can cause discoloration throughout the wood, via the tree's sap, in addition to the dramatically contrasting (mostly) blue and (sometimes) green trails which surround the small tunnels they chew. The beetles prefer wood that is not soaking wet, but that is in the beginning stages of drying. Once kiln dried, they will not re-infest.
