Barker et al., 1998. Zoo Biology, 17 (2): 123-134

A comprehensive summary of the nutritional content of selected whole invertebrates used in zoo feeding programmes is presented. Proximate composition, fat-soluble vitamins and minerals in meal worms (Tenebrio molitor and Zophobas morio [ Z. atratus]), crickets (Acheta domesticus), waxworms (Galleria mellonella), fruit flies (Drosophila melanogaster), and earthworms (Lumbricus terrestris) were estimated. All species had a water content >50% of their body weights. Larval invertebrates had higher fat content (x>30% DM) than adult species. Total N ranged from 5.2% DM (earthworms) to 10.3% DM (adult crickets), whereas chemically bound N comprised 3-10% of total N in all invertebrates. NDF, used as a measure of chitin, averaged 15.3% DM for all species except wild-caught earthworms, which were higher (51% DM). Vitamin E concentrations ranged from 15 IU/kg DM (meal worms) to 509 IU/kg DM (waxworms). Vitamin A levels were undetectable (fruit flies) to low in all samples; none met the recommended dietary vitamin A levels established for domestic carnivores. Insects had low Ca (x=0.11%) and imbalanced Ca to P ratios except for pinhead crickets. Insects sampled contained sufficient levels of Cu, Fe, Mg, P and Zn to meet known requirements of domestic birds and mammals, whereas super-meal worms and waxworms contained deficient levels of Mn. Earthworms appeared to meet dietary mineral requirements, based on domestic bird and mammal recommendations.