Beetles Identification Guide

INTRODUCTION
This book is intended to provide extension entomologists and naturalists
with an identification guide to the common beetles associated with stored
products in Canada. Only the adult stage is dealt with in this book. The
distribution and economic importance of each species are discussed; information
on the biology is omitted, because it is the subject of a recent publication
(Campbell et al. 1989).
Beetles represent the largest natural order in the animal kingdom; more
than 9000 species are estimated to occur in Canada (Campbell 1979). The
main characteristic of the adult beetle is the modification of the anterior
wings, the elytra, into a stiff cover that protects the membranous posterior
wings (if present) and the abdomen when the beetle is at rest. In a few species,
such as the female of Thylodrias contractus, the elytra have been secondarily
lost. Like many other insects, beetles have a complete
metamorphosis, with four distinct stages in their life cycle: egg, larva, pupa,
and adult. More information about the general morphology and biology of
Coleoptera can be found in Crowson (1981) and Halstead (1986).
Every year, large quantities of stored products are destroyed or contaminated
because of the presence of arthropods, and beetles are by far the most
important group of animals attacking these products (Hinton 1945). Over 600
species around the world have been found associated with stored products, and
120 of these are dealt with here (see “List of beetles associated with stored products
in Canada”). The species include those established or found more or less
regularly in Canada and associated with stored products. Less than half of these
species actually eat the product or one of its constituents. In fact, many of the
stored-product species feed on fungi or on dead arthropods and small mammals
present in places where food is stored. Species known in Canada only from interceptions
at ports of entry have not been included, except for Trogoderma
granarium. Also excluded are the species that are general predators, such as
Carabidae and Staphylinidae, and those attacking structural woodwork in buildings,
such as many Anobiidae, Bostrichidae, and Cerambycidae. Although some
of these species may be found in buildings where food is stored, they are only
incidental and thus are not considered to be associated with stored products.
This guide is organized in two parts. The first includes keys and illustrations
of the common stored-product species in Canada. The second part presents, for
each species treated, sections on diagnosis and sexual dimorphism as well as information
on distribution and economic importance.
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