Quantitative genetics of butterfly wing patterns

A method for surface nitriding boron filaments to make the filaments useful as reinforcement agents in composite materials. The method involves initially forming a liquid boron oxide coating on the filament, for example, by heating the filament at temperatures of from about 560 DEG C. to 800 DEG C. in an oxidizing atmosphere and then converting the liquid oxide coating to a solid, continuous boron nitride coating by, for example, heating the filament at temperatures of from about 600 DEG C. to 1,100 DEG C. in an nitrogen-containing atmosphere.