I believe she spends all her energy aerating and protecting the eggs, and doesn't eat for ??? long, correct Laz?
Hence Octos literally starve themselves to death.....
dhaas
That is what the studies suggest. Depending on the species, the method of caring for the eggs defers. In this particular individual (O. vulgaris), she is known to attach the eggs to the roof of her den. Everything I've ever read on octopus has given a vast difference of time ranges for egg development -- somewhere between one and five months. The one other time I saw O. vulgaris with eggs (last year) she was in her den for over 2 months before finally disappearing.
Other species such as the sand dwellers (Mimics, etc.) are known to carry their eggs under their mantles where ever they go. I have yet to see our local mimic, O. defilippi, carrying eggs but I'm hoping I will some day. 
It is believed the female octopus (O. vulgaris) never leaves the den and does not feed during egg development. She sits there and aerates the eggs the whole time. From my personal observations I have noticed their breathing rate is much higher elevated than normal. I will continue to observe our little octo momma and see what results turn out.
One thing is certain in my book of observations... Octos are very seasonal. In the past two months an explosion of octos have occured throughout our waters and it is now slowly starting to dwindle. Maybe another years worth of notes with regards to prey availability and conditions might help me start to find some kind of pattern to them. It's all very exciting, although nowhere being scientific as it's only the observations of little ol' (unscientific) me.
As a side note, the most interesting thing I've read about octopus is the fact that they believe they have a hormone in their body that indicates to them how long they will live and thus use the opportunity to reproduce.
Laz