Re: How many calories C.elegans, B. anynana and Melanogaster consume daily

A good source for this would be:

The Allometry of Growth and Reproduction
M.J. Reiss
Cambridge University Press
Cambridge, UK  1989
(1991 paperback)
ISBN 0 521 42358 9

There's a lot of material here but on p. 59 of the paperback version, 
Reiss cites Hemmingsen's analysis of metabolic rates for homeotherms, 
poikilotherms and unicellular organisms.  Of particular note is the 
equation for poikilotherms:

BMR= 0.144*(W**0.738)

where BMR is in cubic centimetres of oxygen per hour and W is body weight 
in grams.

I hope this helps.