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Insects­and Other­Arthropods­as Food

Mark Finke, Liz Koutsos, and Diane Winn

­ Introduction:­Definitions­and Taxonomy

It is estimated that 61% of North American birds are primarily insectivorous, with an additional 28%
partially insectivorous (Capinera 2010). Tremendous variability is shown in the types of insects
consumed by different avian species. Additionally, there may be seasonal changes in feeding behav-
ior, as is the case for some birds during breeding season, presumably to enhance their nutrient
intake for egg production and delivery of optimal nutrition to growing young. The purpose of this
chapter is to provide a nutritional primer for wildlife professionals raising nestlings of species that,
in the wild, would be fed predominantly insects or other arthropods (Figures 41.1 and 41.2).
Arthropods are the largest group of animals on earth. While insects are the most well-known of
the arthropods, other groups include, spiders, ticks, mites and scorpions (Arachnida); woodlice/
pillbugs, crabs, crayfish and shrimp (Crustacea); millipedes (Diplopoda); and centipedes
(Chilopoda). The arthropods familiar to most people are insects, which have a body with three
distinct regions (head, thorax, and abdomen) and three pairs of legs. Although many animals are
termed insectivores, most of them prey on a variety of invertebrates, some of which are likely an
important source of select nutrients that may not be obtained in sufficient quantities from most
insect species.
Generally, insects fall into two fairly distinct groups: those with simple metamorphosis (hem-
imetabolous) and those with complete metamorphosis (holometabolous). The young of hemime-
tabolous insects are called nymphs, and in most cases they resemble adults, sharing similar habitats
and food. Examples of hemimetabolous insects include crickets, grasshoppers, and roaches. In
contrast, the young of holometabolous insects are called larvae and are distinct from the adults
both in appearance and food habits. The larvae are essentially specialized to accumulate nutrients,
while adult holometabolous insects are specialized for dispersion and reproduction. Examples of
holometabolous insects include beetles, butterflies and moths, flies, and ants.
More than 1 000 000 species of insects have been named, and there are an estimated 5.5 million
species worldwide grouped into 31 orders (Wheeler et al. 2001; Stork 2018). While an in-depth
review of insect taxonomy is not required, some of the major orders of insects likely used as food
by those who gather wild insects include beetles (Coleoptera), bees and ants (Hymenoptera), flies
(Diptera), true bugs and cicadas (Hemiptera), grasshoppers and crickets (Orthoptera), butterflies
and moths and their larvae (Lepidoptera), and cockroaches (Blattodea). In addition to insects,

Hand-Rearing Birds, Second Edition. Edited by Rebecca S. Duerr and Laurie J. Gage.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.