Pyrrhocoris apterus

Geographic Range

European firebug's ( Pyrrhocoris apterus ) endemic range stretches from central and southern Europe to western China, which is mostly in the Palearctic region and parts of the Oriental region. They are, however, invasive to the Neartic region, Neotropical region, some parts of the Oriental region, and Australian region due to human activity. They have currently expanded their territory range into the states of Utah and Idaho within the United States, Central America, India, and to parts of Australia.

• Biogeographic Regions
• nearctic nearctic
  • introduced introduced
• palearctic palearctic
  • native native
• neotropical neotropical
  • introduced introduced
• australian australian
  • introduced introduced

Habitat

European firebugs are terrestrial, meaning they live on land, and generally inhabit forests. They typically occupy the tree trunks and canopies of trees they use as food sources like Tilia cordata . They may also be found on the ground near these same trees, living in leaflitters and rock crevices. Moreover, these bugs can be found in urban environments, occupying houses and other buildings.

• Habitat Regions
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest

• Other Habitat Features
• urban urban

Physical Description

European firebugs are ectothermic, meaning they use the environment to regulate their body temperature, and are bilaterally symmetrical, meaning their body can be split into two identical halves. Body length ranges from 6.5 mm to 12 mm. These bugs also have black and red coloration. The main body has a red base color with a distinguished black pattern of two pairs of black spots and other shapes overtop. They have three pairs of black walking legs and one pair of segmented antennae. Both males and females may have one of three wing types: brachypterous (short-winged), macropterous (fully winged), or apterous (wingless). Furthermore, young European firebugs have some physical differences. Eggs start off white in color and eventually turn a yellowish-red color. Nymphs look more similar to adults. They start off smaller in size, but they have the same black and red coloration. The pattern, however, differs slightly: two large black sections on the upper back followed by three small black dots. Also, nymphs do not have fully developed wings.

• Other Physical Features
• polymorphic polymorphic

Development

European firebugs undergo incomplete or simple metamorphosis. The process typically takes 2 to 3 months to complete. They first begin as oval-shaped eggs, which turn from white to yellow as embryonic differentiation occurs. Eggs typically hatch between 10-14 days, starting from mid-April. Then, they develop into nymphs, sexually immature forms that look very similar to the adult. Nymphs go through 5 growing stages. After the final growing stage, the nymphs develop into adult insects from July to September. Generally, there is one generation per year. Under warmer temperature conditions, however, 2 generations may be produced in a year. Moreover, during winter, adults undergo a process called diapause: a phase where growth is suspended in response to harsh seasonal conditions.

• Development - Life Cycle
• metamorphosis metamorphosis
• diapause diapause

Reproduction

European firebugs form tandems, or mating pairs of males and females, for various lengths of time, ranging from 12 hours to several days. Females typically mate with multiple males before laying eggs in order to replenish their sperm supply and maximize the amount of fertilized eggs they lay. They also store sperm from each copulation to use for later. Males, however, may partake in prolonged tandems as a form of mate guarding to reduce sperm competition with other males. Mate-guarding is more predominantly seen with larger, younger females since larger size and younger age mean a higher reproductive capacity.

• Mating System
• polyandrous polyandrous

European firebugs are gonochoric and reproduce sexually with internal fertilization, meaning there are two sexes, males and females, and genetic material is combined from two individuals. These insects form tandems, or mating pairs of the opposite sex. Females typically mate with multiple males prior to laying eggs, and they may store sperm to fertilize eggs later. Repeated matings help maximize the female's chances of laying more fertilized eggs. Moreover, mating typically occurs during the early spring (March-April) and declines in later spring to winter. Females generally lay 40-80 eggs in their lifetime.

• Key Reproductive Features
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • internal internal
• oviparous oviparous
• sperm-storing sperm-storing
• delayed fertilization delayed fertilization

The literature does not report any form of parental investment.

• Parental Investment
• no parental involvement

Lifespan/Longevity

Generally, European firebugs live from 1 to 2 years. Males also tend to live longer than females.

Behavior

European firebugs are both terricolous, meaning they live on the ground, and aboreal, meaning they live in trees. They are also both solitary and social insects. These bugs do spend time living on their own, but in the fall they typically aggregate into dense populations at the bases of trees they use as a food source. During summer, however, these insects may occupy the tree trunks and canopies to avoid being parasitized by mites like Hemipteroseius adleri . These insects may also fly if they are the brachypterous (short-winged) and macropterous (full-winged) morphs. If they are the apterous morph (wingless), they move around via walking.

• Key Behaviors
• arboreal arboreal
• terricolous
• flies
• motile motile
• solitary solitary
• social social

Communication and Perception

European firebugs communicate chemically using pheromones. Specific aggregation and contact pheromones are used to tell these insects to form their dense population groups. Conversely, they have a warning response with pheromones that will tell them to separate from their aggregations.

• Communication Channels
• chemical chemical

• Other Communication Modes
• pheromones pheromones

• Perception Channels
• chemical chemical

Food Habits

European firebugs are mainly granivores, meaning they generally eat seeds. They insert a stylet mouthpart into their food source to eat. These insects typically feed from three families of plants: Tiliaceae , Malvaceae , and Fabaceae ; however, they may feed from others as well. Some specific plants they may use for food include the following: Robinia pseudocacia , Althaea officinalis , Malva neglecta , Tilia cordata , and Tilia platyphyllos . Adults prefer to eat from Robinia pseudocacia and Althaea officinalis . Larvae, however, may show some preference for eating Robinia pseudocacia , Althaea officinalis , and Tilia platyphyllos . Although not common, there has been reports of predation and cannibalism in these insects if food resources are limited.

• Primary Diet
• herbivore herbivore
  • granivore granivore

• Animal Foods
• insects

• Plant Foods
• seeds, grains, and nuts

Predation

European firebugs have defensive glands as both nymphs and adults to deter predators. Nymphs have posterior dorsoabdominal glands and adults have metathoracic glands. These glands release foul-smelling chemicals. They also have aposematic coloration with their red and black pattering to warn predators of their toxicity. Moreover, formations of aggregations, or groups, decrease predation in these insects as well. European firebugs will also use alarm pheromones to signal dispersal from aggregations if needed. These insects may even regurgitate fluids to deter predators. Known predators of this species include birds, mammals, amphibians, and insects like ants. Specific species are not reported in the literature.

• Anti-predator Adaptations
• aposematic aposematic

Ecosystem Roles

European firebugs are prey for other organisms like ants, birds, mammals, and amphibians. They are also used as hosts by the mite Hemipteroseius adleri .

Economic Importance for Humans: Positive

European firebugs serve as an important species for research in many fields of study, including but not limited to endocrinology, ecology, biochemistry, and morphology.

• Positive Impacts
• research and education

Economic Importance for Humans: Negative

European firebugs are a nuisance in urban environments, infesting homes and other buildings, especially during the winter. If they feel threatened, they will release a horrible-smelling odor and regurgitated gut fluids. If crushed, they may permanently stain surfaces of a house. Fortunately, they do not injure humans or pets.

• Negative Impacts
• household pest

Conservation Status

The European firebug has no special conservation status.

Other Comments

European firebugs belong to the insect order Hemiptera , otherwise known as true bugs.

Additional Links

Encyclopedia of Life

Contributors

Justine Negron (author), Colorado State University.

References

Candan, S., N. Kocakoglu. 2022. Structures of spermatheca and eggs of the red firebug, Pyrrhocoris apterus (L. 1758) (Heteroptera: Pyrrhocoridae), based on optical and scanning electron microscopy. Gaza University Journal of Science , 35 (2): 333-334. Accessed August 25, 2023 at https://doi.org/10.35378/gujs.892833 .

Endrestol, A., S. Roth. 2020. The firebug Pyrrhocoris apterus (Linnaeus, 1758) (Hemiptera, Heteroptera) new to the Norwegian fauna – with an explosive expansion in Northern Europe. Norwegian Journal of Entomology , 67: 81-90. Accessed November 25, 2023 at http://www.entomologi.no/journals/nje/2020-1/pdf/nje-vol67-no1-2020-81-90-endrestol.pdf .

Farine, J., O. Bonnard, R. Brossut, J. Le Quere. 1992. Chemistry of defensive secretions in nymphs and adults of fire bug,Pyrrhocoris apterus L. (Heteroptera, Pyrrhocoridae). Journal of Chemical Ecology , 18: 1673–1682. Accessed August 24, 2023 at https://link.springer.com/article/10.1007/BF02751094 .

Hejníková, M., M. Nouzova, C. Ramirez, F. Fernandez-Lima, F. Noriega, D. Doležel. 2022. Sexual dimorphism of diapause regulation in the hemipteran bug Pyrrhocoris apterus. Insect Biochemistry and Molecular Biology , 142: 103721. Accessed September 01, 2023 at https://doi.org/10.1016/j.ibmb.2022.103721 .

Honek, A., K. Sramkova. 1976. Behavioral regulation of developmental cycle in P. apterus L. (Heteroptera: Pyrrhocoridae). Oecologia , 24: 277-281. Accessed November 25, 2023 at https://link.springer.com/article/10.1007/BF00345479 .

Honek, A., Z. Martinkova, M. Brabec. 2019. Mating activity of Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae) in nature. European Journal of Entomology , 116: 187-193. Accessed September 19, 2023 at https://www.eje.cz/pdfs/eje/2019/01/20.pdf .

Honek, A., Z. Martinkova. 2022. Effect of male body size on female reproduction in Pyrrhocoris apterus (L.) (Heteroptera, Pyrrhocoridae). Insects (2075-4450) , 13 (10): 902-N.PAG. Accessed September 06, 2023 at https://ezproxy2.library.colostate.edu/login?url=https://search.ebscohost.com/login.aspx?direct=true&AuthType=cookie,ip,url,cpid&custid=s4640792&db=asn&AN=159905617&site=ehost-live .

Kristenová, M., A. Exnerová, P. Stys. 2011. Seed preferences of Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae): Are there specialized trophic populations?. European Journal of Entomology , 108 (4): 581-586. Accessed August 25, 2023 at https://www.proquest.com/docview/898605337?accountid=10223 .

Käfer, H., H. Kovac, A. Stabentheiner. 2023. Habitat temperatures of the red firebug, Pyrrhocoris apterus: The value of small-scale climate data measurement. Insects , 14 (11): 843. Accessed November 25, 2023 at https://doi.org/10.3390/insects14110843 .

Mata, L., B. Vogel, E. Palma, M. Malipatil. 2022. The arrival and spread of the European firebug (Pyrrhocoris apterus) in Australia as documented by citizen scientists. Urban Naturalist , 9: 1-7. Accessed September 10, 2023 at https://eaglehill.us/urna-pdfs-notes/urna-003-Mata.pdf .

Richardson, K., E. Hodgson. 2023. "Red Firebug (Pyrrhocoris apterus)" (On-line pdf). Utah State University Extension. Accessed August 24, 2023 at https://digitalcommons.usu.edu/cgi/viewcontent.cgi?referer=https://www.google.com/&httpsredir=1&article=1945&context=extension_curall .

Schöfl, G., M. Taborsky. 2002. Prolonged tandem formation in firebugs (Pyrrhocoris apterus) serves mate-guarding. Behavioral Ecology and Sociobiology , 52 (5): 426-433. Accessed October 24, 2023 at https://www.jstor.org/stable/4602161 .

Stokes, B., E. Wenninger. 2022. "Red Fire Bug — A New Idaho Invader?" (On-line). University of Idaho Extension. Accessed November 23, 2023 at https://www.uidaho.edu/extension/publications/bul/bul1019#:~:text=Red%20fire%20bugs%20are%20strikingly,respect%20to%20their%20wing%20development. .

Svádová, K., A. Exnerová, P. Štys. 2014. Gregariousness as a defence strategy of moderately defended prey: experiments with Pyrrhocoris apterus and avian predators. Behaviour , 151 (11): 1617-1640. Accessed November 12, 2023 at https://www.jstor.org/stable/24526344 .

Zemek, R., R. Socha. 2010. Trends in Acarology . New York: Springer Science+Business Media B.V.. Accessed August 24, 2023 at https://doi.org/10.1007/978-90-481-9837-5_59 .

Žďárek, J. 1970. Mating behaviour in the bug, Pyrrhocoris apterus L. (Heteroptera): Ontogeny and its environmental control. Behaviour , 37 (3/4): 253-268. Accessed October 24, 2023 at https://www.jstor.org/stable/4533355 .