''Coreus marginatus'' is a
herbivorous
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...
species of
true bug
Hemiptera (; ) is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from to around , ...
in the family
Coreidae
Coreidae is a large family of predominantly sap-sucking insects in the Hemipteran suborder Heteroptera. The name "Coreidae" derives from the genus ''Coreus'', which derives from the Ancient Greek () meaning bedbug.
As a family, the Coreidae ar ...
. It is commonly known as the dock bug as it feeds on the leaves and seeds of
docks and sorrels. It is a medium-sized speckled brown insect, between 13 and 15 mm long as an adult, with a broad
abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...
.
It occurs throughout
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
,
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
and northern Africa.
It is often found in dense vegetation, such as
hedge
A hedge or hedgerow is a line of closely spaced shrubs and sometimes trees, planted and trained to form a barrier or to mark the boundary of an area, such as between neighbouring properties. Hedges that are used to separate a road from adjoin ...
rows and wasteland.
Taxonomy
This species was among the first
Hemiptera formally described in the scientific literature by the Swedish biologist
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
in 1758, under the name ''Cimex marginatus''. It was transferred to the genus ''
Coreus
''Coreus'' is a genus of leaf-footed bug in the Coreinae subfamily. It is the type genus for the Coreidae
Coreidae is a large family of predominantly sap-sucking insects in the Hemipteran suborder Heteroptera. The name "Coreidae" derives fro ...
'' by the Danish zoologist
Johan Fabricius in 1794. It has numerous
synonyms and was historically placed in the genus ''
Syromastus
''Syromastus'' is a true bug genus in the family Coreidae
Coreidae is a large family of predominantly sap-sucking insects in the Hemipteran suborder Heteroptera. The name "Coreidae" derives from the genus ''Coreus'', which derives from the A ...
''.
The
specific epithet ''
marginatus'' refers to the prominent margins of the abdomen.
Description
The head,
pronotum
The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum ( dorsal), the prosternum (ventral), and the propleuron (lateral) on e ...
and abdomen of an adult dock bug are speckled reddish brown. The
antennae are composed of four segments, red-orange in colour except for the final fourth segment which is black. Between the antennae are two small projections, known as antenniferous tubercles, which can be used to distinguish this species from other superficially similar species.
[Southwood, T. R. E. and D. Leston, (1959) ''Land and Water Bugs of the British Isles'' Frederick Warne & co.] The pronotum has angular upward facing projections and the
scutellum is clearly visible. The rounded edge of the abdomen has lighter coloured markings. Adults are between long and males are typically smaller than females but have longer antennae.
Young nymphs look different in appearance to the adults. They are heavily spined, less uniform in colouration and have disproportionately large antennae compared to their body size. Older nymphs looks more similar to adults with a more uniform speckled brown colouration but lacking developed wings.
Like other Coreidae, ''Coreus marginatus'' has scent glands with small pores in the middle of its
thorax
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...
which can release strong-smelling, irritating,
volatile defensive chemicals when disturbed. The pores have an
ultrastructure
Ultrastructure (or ultra-structure) is the architecture of cells and biomaterials that is visible at higher magnifications than found on a standard optical light microscope. This traditionally meant the resolution and magnification range of a co ...
composed of mushroom-like structures that are connected to each other via ridges and
trabecules. The chemical composition of the scent gland secretions is similar between males and females, although the relative proportions are different. In females the most prevalent chemical compound is
hexanoic acid
Caproic acid, also known as hexanoic acid, is the carboxylic acid derived from hexane with the chemical formula . It is a colorless oily liquid with an odor that is fatty, cheesy, waxy, and like that of goats or other barnyard animals. It is ...
while in males it is
stearic acid.
Distribution
Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...
originally described the species from Europe with only one of his specimens having a specific locality of England. Other early specimens collected by
Goeze are from France The current distribution is extensive and covers: Europe, from Portugal to Finland; Asia, from Russia to China; and Africa, known only from Algeria.
Life cycle
Like other Coreidae the dock bug has an annual life cycle consisting of an egg followed by five successive
nymphal 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 ...
s before becoming an adult.
It
overwinters
Overwintering is the process by which some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions (cold or sub-zero temperatures, ice, snow, limited food supplies) make normal activ ...
as an adult and copulates in the typical heteropteran back-to-back position, laying large brown eggs between late May and early July. The eggs take around 3 to 4 weeks to hatch. The young nymphs will feed on leaves and stems while the older nymphs, like the adults, feed on seeds. The nymphs mature to adults from August onwards.
Diet
The dock bug is
herbivorous
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...
and feeds on a wide variety of plants from different families. While the common name in English refers to its preferred diet of
docks and sorrels and other plants in the family
Polygonaceae
The Polygonaceae are a family of flowering plants known informally as the knotweed family or smartweed—buckwheat family in the United States. The name is based on the genus '' Polygonum'', and was first used by Antoine Laurent de Jussieu in 1 ...
, they also readily feed on certain species of
Asteraceae
The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...
and
Rosaceae. Adults are known to feed on
raspberry,
gooseberry and sometimes
blackcurrant.
Gallery
References
{{Taxonbar, from=Q1126211
Coreini
Bugs described in 1758
Hemiptera of Europe
Taxa named by Carl Linnaeus