The Heteroptera are a group of about 40,000 species of insects in the order
Hemiptera
Hemiptera (; ) is an order (biology), order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, Reduviidae, assassin bugs, Cimex, bed bugs, and shield bugs. ...
. They are sometimes called "true bugs", though that name more commonly refers to the Hemiptera as a whole. "Typical bugs" might be used as a more unequivocal alternative, since the heteropterans are most consistently and universally termed "bugs" among the Hemiptera. "Heteroptera" is Greek for "different wings": most species have
forewing
Insect wings are adult outgrowths of the insect exoskeleton that enable insects to fly. They are found on the second and third thoracic segments (the mesothorax and metathorax), and the two pairs are often referred to as the forewings and hindwin ...
s with both membranous and hardened portions (called
hemelytra); members of the primitive sub-group
Enicocephalomorpha
Enicocephaloidea is a sole superfamily within the infraorder Enicocephalomorpha of the hemipteran suborder Heteroptera ("true bugs"). The group was formerly thought to be related to the Reduviidae because of similarities in head structure but t ...
have completely membranous wings.
The name "Heteroptera" is used in two very different ways in modern classifications. In
Linnean nomenclature
In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
, it commonly appears as a
suborder
Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...
within the
order Hemiptera, where it can be
paraphyletic
In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...
or
monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
depending on its delimitation. In
phylogenetic nomenclature
Phylogenetic nomenclature is a method of nomenclature for taxa in biology that uses phylogenetic definitions for taxon names as explained below. This contrasts with the traditional approach, in which taxon names are defined by a '' type'', which ...
, it is used as an unranked
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
within the
Prosorrhyncha
The name Prosorrhyncha is a name (proposed by Sorensen et al. 1995) for a suborder of Hemiptera, comprising a grouping of the traditional taxon "Heteroptera" plus its sister taxon, the family Peloridiidae (often classified as a suborder itself). T ...
clade, which in turn is in the Hemiptera clade. This results from the realization that the
Coleorrhyncha
Coleorrhyncha or Peloridiomorpha, also known as moss bugs or beetle bugs, are a suborder of Hemiptera and represent an ancient lineage of moss-feeding insects. They show some similarities to the Heteroptera but have been considered distinct. It ha ...
are just "
living fossil
A living fossil is an extant taxon that cosmetically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossi ...
" relatives of the traditional Heteroptera, close enough to them to be united with that group.
The infraorders
Leptopodomorpha
Leptopodomorpha is an infraorder of insects in the order Hemiptera (true bugs). Leptopodomorpha is an infraorder of the order Heteroptera that contains more than 380 species. These small insects are also called shore bugs, or spiny shore bugs. As ...
,
Gerromorpha
The Gerromorpha comprise an infraorder of insects in the "true bug" order Hemiptera. These "typical" bugs (suborder Heteroptera) are commonly called semiaquatic bugs or shore-inhabiting bugs. The Ochteroidea (infraorder Nepomorpha are also foun ...
, and
Nepomorpha
Nepomorpha is an infraorder of insects in the "true bug" order (Hemiptera). They belong to the "typical" bugs of the suborder Heteroptera. Due to their aquatic habits, these animals are known as true water bugs. They occur all over the world o ...
, comprise a significant component of the world’s aquatic and semiaquatic insects. There are 23 families, 343 genera and 4,810 species group taxa within these three infraorders.
Most of the remaining groups that are common and familiar are in the
Cimicomorpha
The Cimicomorpha are an infraorder of insects in the order Hemiptera, the true bugs. The rostrum and other morphology of all members apparently is adapted to feeding on animals as their prey or hosts. Members include bed bugs, bat bugs, assassi ...
and
Pentatomomorpha
The Pentatomomorpha comprise an infraorder of insects in the true bug order Hemiptera. It unites such animals as the stink bugs (Pentatomidae), flat bugs (Aradidae), seed bugs (Lygaeidae and Rhyparochromidae), etc. They are closely related to t ...
.
Classification
![Heteroptera morphology-d](https://upload.wikimedia.org/wikipedia/commons/a/a0/Heteroptera_morphology-d.svg)
The use of the name "Heteroptera" has had the rank of
order, dating back to 1810 by
Pierre André Latreille
Pierre André Latreille (; 29 November 1762 – 6 February 1833) was a French zoologist, specialising in arthropods. Having trained as a Roman Catholic priest before the French Revolution, Latreille was imprisoned, and only regained his freedom ...
. Only recently has it been relegated to a subsidiary rank within a larger definition of Hemiptera, so many reference works still include it as an order. Whether to continue treating it as a suborder is still a subject of some controversy, as is whether the name itself should ever be used, although three basic approaches ranging from abolishing it entirely to maintaining the
taxonomy
Taxonomy is the practice and science of categorization or classification.
A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...
with a slight change in
systematics
Biological systematics is the study of the diversification of living forms, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees (synonyms: cladograms, phylogenetic tre ...
is proposed, two of which (but not the traditional one) agree with the
phylogeny
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...
. The competing classifications call for a preference for two suborders versus one when the "living fossil" family
Peloridiidae
The Peloridiidae or moss bugs are a family of true bugs, comprising eighteen genera and thirty-four species. They are small, ranging in length from 2 to 4 mm, rarely seen, peculiarly lumpy, flattened bugs found in Patagonia (Argentina and Chi ...
is taken into consideration:
In one revised classification proposed in 1995, the name of the suborder is
Prosorrhyncha
The name Prosorrhyncha is a name (proposed by Sorensen et al. 1995) for a suborder of Hemiptera, comprising a grouping of the traditional taxon "Heteroptera" plus its sister taxon, the family Peloridiidae (often classified as a suborder itself). T ...
, and Heteroptera is a rankless subgroup within it. The only difference between Heteroptera and Prosorrhyncha is that the latter includes the family
Peloridiidae
The Peloridiidae or moss bugs are a family of true bugs, comprising eighteen genera and thirty-four species. They are small, ranging in length from 2 to 4 mm, rarely seen, peculiarly lumpy, flattened bugs found in Patagonia (Argentina and Chi ...
, which is a tiny
relictual group that is in its own
monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...
superfamily and infraorder. In other words, the Heteroptera and Prosorrhyncha ''sensu'' Sorensen et al. are identical except that Prosorrhyncha contains one additional infraorder, called
Peloridiomorpha
Coleorrhyncha or Peloridiomorpha, also known as moss bugs or beetle bugs, are a suborder of Hemiptera and represent an ancient lineage of moss-feeding insects. They show some similarities to the Heteroptera but have been considered distinct. It ha ...
(comprising only 13 small genera). The ongoing conflict between traditional, Linnaean classifications and nontraditional classifications is exemplified by the problem inherent in continued usage of the name Heteroptera when it no longer can be matched to any standard Linnaean rank (as it falls below suborder but above infraorder). If this classification succeeds, then the "Heteroptera" grouping may be discarded, but in that case it is likely that no ranks will be used at all according to the standards of
phylogenetic nomenclature
Phylogenetic nomenclature is a method of nomenclature for taxa in biology that uses phylogenetic definitions for taxon names as explained below. This contrasts with the traditional approach, in which taxon names are defined by a '' type'', which ...
.
In the traditional classification, the Peloridiidae are retained as their own suborder, called
Coleorrhyncha
Coleorrhyncha or Peloridiomorpha, also known as moss bugs or beetle bugs, are a suborder of Hemiptera and represent an ancient lineage of moss-feeding insects. They show some similarities to the Heteroptera but have been considered distinct. It ha ...
; "Heteroptera" is treated the same. Functionally, the only difference between this classification and the preceding is that the former uses the name Prosorrhyncha to refer to a particular clade, while the traditional approach divides this into the
paraphyletic
In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...
Heteroptera and the
monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
Coleorrhyncha. Many believe it is preferable to use only one name because the characteristics of the two traditional suborders are too closely related to be treated as separate.
Alternatively,
[Cassis, Gerasimos & Gross, Gordon (1995): Australian Biological Resources Study â€]
Hemiptera: Heteroptera (Coleorrhyncha to Cimicomorpha). Gerrids, Reduviids, Water-striders
Version of June 30, 1995. Retrieved July 28, 2008. the modified approach of placing Coleorrhyncha 'within' the Heteroptera can be used. Indeed, as that solution preserves the well-known Heteroptera at the taxonomic rank they traditionally hold while making them a good
monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
group, it seems preferable to the paraphyletic "Heteroptera" used in older works. In that case, the "core" Heteroptera could be considered a
section
Section, Sectioning or Sectioned may refer to:
Arts, entertainment and media
* Section (music), a complete, but not independent, musical idea
* Section (typography), a subdivision, especially of a chapter, in books and documents
** Section sign ...
– as yet unnamed, mainly because the Prosorrhyncha were proposed earlier – within the "expanded" Heteroptera, or the latter could simply be described as consisting of a
basal "living fossil" lineage and a more
apomorph
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...
ic main radiation. Whether the name "Coleorrhyncha" is to be retained for the basal lineage or whether the more consistent "Peloridiomorpha" is used instead is a matter of taste, as described below.
Separate from the question of the actual "closeness" of Heteroptera and Coleorrhyncha is the potential disruption to traditional construction of names; there seems to be reluctance among hemipterists to abandon the use of "Heteroptera". This can be seen by the name itself, as it is a violation of convention to use the ending "-ptera" for any rank above genus other than an order – though since it is a convention rather than a
mandatory rule of Linnean nomenclature, taxonomists are technically free to violate it (which is why, for example, not all insect orders end in "-ptera", e.g.,
Odonata
Odonata is an order of flying insects that includes the dragonflies and damselflies. Members of the group first appeared during the Triassic, though members of their total group, Odonatoptera, first appeared in Late Carboniferous.
The two comm ...
). However, in most cases when such conventions are violated, it does not create an internal conflict as in the present case (that is, the order Hemiptera has a suborder named Heteroptera, which is an internal conflict). At least some hemipterists argue that the name Heteroptera should be dropped entirely to eliminate this internal conflict, though the third possibility offers a workaround. In that case, to achieve full consistency of names "Coleorrhyncha" would probably be dropped in favor of "Peloridiomorpha".
References
Further reading
*
External links
*Heteropteran Systematics Lab at University of California, Riverside http://heteroptera.ucr.edu
Identification guide to UK Hemiptera
{{Authority control
Hemiptera
Insect suborders
Extant Triassic first appearances