The firebug, ''Pyrrhocoris apterus'', is a common

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pa ...

of the family

Pyrrhocoridae Pyrrhocoridae is a family of insects with more than 300 species world-wide. Many are red coloured and are known as red bugs and some species are called cotton stainers because their feeding activities leave an indelible yellow-brownish stain on ...

. Easily recognizable due to its striking red and black coloration, it may be confused with the similarly coloured though unrelated '' Corizus hyoscyami'' (cinnamon bug or squash bug). ''Pyrrhocoris apterus'' is distributed throughout the

Palaearctic The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Sibe ...

from the Atlantic coast of Europe to northwest China. It has also been reported from the United States, Central America, and India, and is also found in Australia. It has been reported as recently expanding its distribution northwards into mainland United Kingdom and eastward on to the coast of the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on ...

. They are frequently observed to form aggregations, especially as immature forms, containing from tens to perhaps a hundred individuals.

Reproduction

Firebugs generally mate in April and May. Their diet consists primarily of seeds from lime trees and mallows ( see below). They can often be found in groups near the base of lime tree trunks, on the sunny side. They can be seen in tandem formation when mating which can take from 12 hours up to 7 days. The long period of copulating is probably used by the males as a form of ejaculate-guarding under high competition with other males.

Development

''P. apterus'' was the subject of an unexpected discovery in the 1960s when researchers who had for ten years been rearing the bugs in

Prague Prague ( ; cs, Praha ; german: Prag, ; la, Praga) is the capital and largest city in the Czech Republic, and the historical capital of Bohemia. On the Vltava river, Prague is home to about 1.3 million people. The city has a temperate ...

Czech Republic The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...

, attempted to do the same at

Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of highe ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

. After the fifth larval

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ...

, instead of developing into adults, the bugs either entered a sixth instar stage, or became adults with larval characteristics. Some of the sixth instars went on to a seventh instar, but all specimens died without reaching maturity. The source of the problem was eventually proven to be the

paper towels A paper towel is an absorbent, disposable towel made from paper. In Britain, paper towels for kitchen use are also known as kitchen rolls, kitchen paper, or kitchen towels. For home use, paper towels are usually sold in a roll of perforated she ...

used in the rearing process; the effect only happened if the paper towels were made in America. The researchers could replicate these results with American newspapers such as the ''

New York Times ''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...

'', but not European newspapers such as ''

The Times ''The Times'' is a British daily national newspaper based in London. It began in 1785 under the title ''The Daily Universal Register'', adopting its current name on 1 January 1788. ''The Times'' and its sister paper '' The Sunday Times'' ( ...

''. The cause was found to be

hormone A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required ...

s found in the native

balsam fir ''Abies balsamea'' or balsam fir is a North American fir, native to most of eastern and central Canada (Newfoundland west to central Alberta) and the northeastern United States (Minnesota east to Maine, and south in the Appalachian Mountains to ...

tree (''Abies balsamea'') used to manufacture paper and related products in America, and in some other North American conifers. This hormone happened to have a profound effect on ''P. apterus'', but not on other insect species, showing the diversification of hormone receptors in the insects. The most potent chemical component was later identified as

juvabione Juvabione, historically known as the paper factor, is the methyl ester of todomatuic acid, both of which are sesquiterpenes (C15) found in the wood of true firs of the genus ''Abies''. They occur naturally as part of a mixture of sesquiterpenes ...

, the methyl

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...

todomatuic acid Juvabione, historically known as the paper factor, is the methyl ester of todomatuic acid, both of which are sesquiterpenes (C15) found in the wood of true firs of the genus ''Abies''. They occur naturally as part of a mixture of sesquiterpenes ...

, which is produced by the trees in response to wounding; it mimics

juvenile hormone Juvenile hormones (JHs) are a group of acyclic sesquiterpenoids that regulate many aspects of insect physiology. The first discovery of a JH was by Vincent Wigglesworth. JHs regulate development, reproduction, diapause, and polyphenisms.The chem ...

closely at the chemical level, defending against vulnerable pests.

Gallery

File:Pyrrhocoridae - Pyrrhocoris apterus-1.JPG, Nymph File:Pyrrhocoris_apterus_group.jpg, Firebugs in

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = '' Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , ...

showing aggregation behavior File:Pyrrhocoris apterus on hibiscus2-Clapiers-4869~2015 10 04.JPG, A firebug feeding on mallow seeds (''

Hibiscus syriacus ''Hibiscus syriacus'' is a species of flowering plant in the mallow family, Malvaceae. It is native to Korea, and south-central and southeast China, but widely introduced elsewhere, including much of Asia. It was given the epithet ''syriacus'' b ...

'').

Possible confusion

Notes

References

External links

Images of firebugs

{{Taxonbar, from=Q486957 Hemiptera of North America Pyrrhocoridae Insects described in 1758 Taxa named by Carl Linnaeus