We derive a formula for correcting the weight of food eaten by an animal for natural weight loss (or gain) of the food, such as through moisture loss and food respiration. The formula is derived using a differential equation to model the loss in fresh weight based on a constant consumption rate and assumptions about the form of the function for weight loss over time of the aliquot. The standard formula is shown to over-estimate the weight of eaten food compared to our theoretically derived formula. This over-estimation is negligible (< 0.2%) for moisture loss below about 10% but increases sharply to 8% when moisture loss is 50%. We illustrate the application of these two formulae using a laboratory study of consumption rate by larvae of a phytophagous insect: the Tasmanian eucalyptus leaf beetle, Chrysophtharta bimaculata (Olivier) (Coleoptera: Chrysomelidae).

Item Type:	Refereed Article
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Forestry sciences
Research Field:	Forest health and pathology
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Forestry
Objective Field:	Hardwood plantations
UTAS Author:	Baker, SC (Associate Professor Sue Baker)
ID Code:	72314
Year Published:	2002
Deposited By:	Plant Science
Deposited On:	2011-08-25
Last Modified:	2011-08-25
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