Published by Utah State University Extension and Utah Plant Pest Diagnostic Laboratory
ENT-126-08
Revised August 2023
Red Firebug (Pyrrhocoris apterus) Kate Richardson, Extension Entomology Specialist • Erin Hodgson, Extension Entomology Specialist
Quick Facts • Red firebug was first discovered in North America in Salt Lake City, Utah, in 2008 and has continued to establish throughout much of Utah and southern Idaho. • These insects feed on seeds from a wide range of plants but typically cause little plant damage that warrants control. • They are a nuisance pest that most often cause problems by congregating in large numbers on homes and buildings or nearby plants. • They often release a foul odor when disturbed or crushed and can permanently stain fabrics and carpets. • Cultural control techniques, such as reducing plant materials around the home and sealing entrances, are best to exclude them from homes.
R
ed firebug, Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae), are true bugs with vibrant red and black coloration. These insects are native to central Europe but are also found in western Siberia, southwestern Mongolia, India, and northwestern China.
In 2008, red firebug was first discovered in North America in southeastern Salt Lake City, Utah, and has been expanding its range since. They are now established throughout Utah and Southern Idaho. Some forms are excellent fliers, and their range will likely continue expanding in urbanized areas. How they arrived in the United States is currently unknown, but it is probable they were transported on plant material from Europe or Asia. In Europe and invaded areas, they feed on a wide range of dry, ripe seeds and are most commonly found on plants in the Malvaceae family.
Fig. 1. Brachypterous (short-winged) adult red firebug.
DESCRIPTION Red firebug adults are 1/4 to 1/2 inch long and similar in size to a boxelder bug. Adult males and females may be apterous (wingless), brachypterous (short-winged), or macropterous (fully winged). The most common form in Utah is the shortened-wing adult (Fig. 1). The characteristic forewing pattern is a red background with two pairs of black spots, and wings are typically held flat against the body at rest. Red firebug antennae have four segments, are slightly enlarged at the end, and are usually at least half the length of the body. The eyes are prominent, almost appearing to come from the “shoulders.” Red firebugs go through simple metamorphosis (egg, nymph, adult) and typically have one generation per year, although some adults can live up to 2 years. The entire life cycle can take 2 to 3 months, depending on the temperature. Overwintered females lay 40 to 80 eggs in a lifetime, starting in April and May. Eggs are white but gradually turn yellow-red before hatching in 10 to 14 days. Red firebug nymphs go through five instars in 17 to 24 days before molting into adults.