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Insects and Other Arthropods as Food 625

other arthropods that might be used in a feeding program include spiders, woodlice/pillbugs, and
millipedes. Although earthworms (Lumbricus terresstris) are not arthropods (they are annelids),
they are included here because of their use by many rehabilitators.

­ Nutritional­Composition­of Insects

The insect species most commonly cultured for food include house crickets (Acheta domesticus),
waxworms (larvae of the wax moth: Galleria mellonella), mealworms and superworms (larvae from
two species of beetles: Tenebrio molitor and Zophobas mori), soldier flies (larvae of the black soldier
fly: Hermetia illucens), fruit flies (Drosophila melanogaster and Drosophila hydeii) and several spe-
cies of roaches. Nutritional information for these species and other feeder invertebrates is summa-
rized in Tables 41.1–41.2 (original sources are Finke 2002, 2013; Oonincx and Dierenfeld 2012). To
facilitate comparisons between different papers, these data have been recalculated from the original
data to express the information on an as-fed basis, because most insects are fed live, with the mois-
ture they naturally contain. More comprehensive reviews of the nutrient content of a wider range
of insects are available (Bukkens 1997; Finke and Winn 2004; Finke and Oonincx 2017).

Moisture,­Protein,­Fat,­and Other­Macronutrients
The moisture, protein, fat, ash, and fiber content of selected invertebrates are shown in Table 41.1.
Whole invertebrates generally contain 55–85% moisture. After water, the nutrient in highest
concentration is usually protein, which is not surprising given the protein-rich exoskeleton of
insects. The protein content of whole invertebrates shown in Table 41.1 ranges from a low of 9.3%
for silkworms to 26.3% for six-spotted roaches. In addition to protein, fat is a major component of
most invertebrates, with the fat content of whole invertebrates ranging from a low of 1.4% for silk-
worms to a high of 29.4% for butterworms. Generally, there is a negative relationship between
insect moisture content and insect fat content, with high-fat insects having less moisture than low-
fat insects. In several instances, insects contain more fat than protein. Generally, female insects
contain more fat than males, and commercially-raised insects usually contain more fat than wild-
caught insects (Finke and Oonincx 2017). Most invertebrates contain only small amounts of ash
(which represents minerals) because they lack the internal calcified skeleton found in vertebrates.
The exceptions are soldier fly larvae and woodlice/pillbugs, both which have a mineralized exo-
skeleton (Oonincx and Dierenfeld 2012; Finke 2013).
Protein is composed of amino acids, and there are a number of published reports on the
amino acid composition of insects that show them to be a good source of protein that
provides sufficient quantities of most of the essential amino acids (Finke 2002, 2013; Finke and
Oonincx 2017).
There are multiple reports on the fatty acid composition of most commercially-raised insect spe-
cies (Finke 2002, 2013, 2015b). Importantly, all the insects tested contained significant amounts of
the essential fatty acids linoleic acid (18 : 2) and linolenic acid (18 : 3). Commercially-raised insects
generally contain higher levels of omega-6 fatty acids and lower levels of omega-3 fatty acids than
wild-caught insects. Long chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahex-
aenoic acid (DHA) are typically only found in any significant amounts in aquatic insects (Ghioni
et al. 1996; Fontaneto et al. 2011). However, the fatty acid content of insects can be modified by
diet, so there may be significant variation between insects of the same species from various suppli-
ers (Finke 2015b; Starčevića et al. 2017). Soft-bodied insects like silkworms usually contain less