I’ve always thought that colour was going to be a useful functional trait for beetles. I’ve seen (or at least I think I’ve seen – I am colour blind!) a shift in colour of elytra/legs in my specimens from young forest to oldgrowth, but how to quantify this I had no idea until recently. Some other authors have used colour categories – but I think it could be a bit more subtle than that. Also, being heavily influenced by Violle’s definition of functional traits (http://onlinelibrary.wiley.com/doi/10.1111/j.0030-1299.2007.15559.x/full), I always prefer continuous quantitative traits.
So I went down the spectrometer path and was quickly overwhelmed by the options. After much research I’ve decides to go with the Ocean Optics USB 4000 http://www.oceanoptics.com/products/usb4000.asp. Possibly overkill – but it’s well recommended and I got a reasonable price in the end. I’m looking forward to testing it out in a couple of weeks!