Familiar beetles include scarabs (sacred symbol of early Egypt), weevils, and tiger, ground, blister, June and leaf beetles. Beetles are well represented as FOSSILS, the earliest known being Upper Permian forms (256-250 million years old). Representatives of all 4 modern suborders occur in Lower Triassic deposits (250-244 million years old). With so diverse a group a specific description is difficult, but most beetles share the following characteristics.
Reproduction and Development
Most Canadian beetles are brown or black, although an extremely wide range of colours and patterns occurs. Colour may be produced by structural modifications to the cuticle (waxy covering), producing metallic greens and blues, etc; or by pigments in the cuticle, producing oranges, reds, yellows, etc.
Interaction with Humans
Others transmit disease: Dutch elm disease is caused by a fungus transmitted by the elm bark beetle. Beetles do very little direct damage to humans and domestic animals. In rare cases, however, domestic animals (eg, horses) may die from eating hay containing dead blister beetles, several species of which contain toxic chemicals which cause blisters on contact with skin.
Some beetles are beneficial. Many predatory species feed on destructive insects, eg, ladybird beetles have been introduced as biological control agents of APHIDS and SCALE INSECTS attacking crops. Families such as ground and rove beetles contain hundreds of species that feed on destructive insects and regulate their populations.
Some species considered highly beneficial in one life stage may cause damage in another life stage (eg, some larval blister beetles feed on GRASSHOPPER eggs, but adults are leaf-feeders, attacking LEGUMES and other plants). Other beetle species are of considerable importance as pollinators, or assist in the decomposition of dead and waste organic material.
Author BEVERLY CAMPBELL AND J.M. CAMPBELL
Links to Other Sites
Canadian Biodiversity Website
A great information source for all budding biologists. Learn about biodiversity theory, natural history, and conservation issues. From McGill’s Redpath Museum.
An extensively illustrated guide to wildlife species found in British Columbia. Covers bats, birds, beetles, bugs and much more. Also features an insect glossary and notes about invasive species. A biogeographic initiative of the Lab for Advanced Spatial Analysis, Department of Geography, UBC.
University of Alberta's E.H. Strickland Entomological Museum
Check out images and information about insect specimens found in the University of Alberta's E.H. Strickland Entomological Museum, one of the most significant insect collections in Canada.
An online guide to benthic invertebrates found in or on the bottom sediments of rivers, streams, and lakes in Ontario and other regions of Canada. From ecospark.ca
Aquatic Invertebrates of Alberta Online Textbook
An online guide to all major groups of Alberta's aquatic invertebrates. Offers illustrated details of the natural history of each group as well as tips on collecting and preserving specimens. A University of Alberta website.