New data on T. pfefferi ?
to quote from the last article:
"Chamaeleo (sic) pfefferi was found at the same location as C. wiedersheimi, around Mende. It was previously only known from Mt. Manengouba and Mt. Nlonako (Wild 1993, Herrmann et al. 1999) until found in the Bamenda Highlands by...
This just up at the New York Times Science section:
http://www.nytimes.com/2010/08/31/science/31oblizard.html?_r=1&src=twt&twt=nytimesscience
Fence lizard eggs hatched at differing rates - Northern populations were faster -seems obvious enough. Read all about it.
off with it
I would remove it. The diffuser does reduce the amount of light reaching the plants.
You can add a bit of foil (mylar or aluminium) to help reflect more light toward the growing area. Place this behind the bulbs and on the outside edges, if you want.