Insect systematics

Prepared by:
Vidya K. C.
Suresh R. Jambagi
M.Sc. (Agri) Agril. Entomology
University of Agricultural Sciences
Dharwad, Karnataka-580005
Email: jambagisuru@gmail.com
GENERAL ENTOMOLOGY
Presentation: 10
Topics : Insect Systematics
Mr. Suresh Jambagi, M.Sc (Agri) Entomology, UAS Dharwad

INSECT SYSTEMATICS
Systematics: It is the theoretical study of classification including the principles, procedures and governing rules. The term
taxonomy is now being replaced by systematics.
Systematics- Is the scientific study of insects and the diversity of organisms including the study of evolutionary affinities.
Importance of systematics study-
1. To know the common structural characters of a group
2. It facilitates to study insects systematically
3. Evolutionary sequences of different group of insects will be learnt
4. Economically important group of insects will be known
History
• Caroles Linnaeus (1707 – 1778) in his tenth edition of systema nature published in 1758 used the binomial system of
nomenclature for the first time for both plants and animals
• This double naming in latin one for the genus and the second for the species has been universally accepted and followed
subsequently but before such an universal acceptance, several scientists started their own codes of nomenclature
• In 1842, Strickland published a code of nomenclature in English and it was called Strickland code. Another code called
‘Dall code” was evolved by the Americans in 1877.

• Similarly some more codes of nomenclature were evolved in France and Germany
• In order to promote stability and universality in the scientific names of animals, an international code of
zoological nomenclature was evolved in 1901 at Berlin. At the 16th session of International congress of
Zoology in Washington, the latest international code of Zoological nomenclature was approved and the same
was revised and published in 1964.
• According to it, the descriptions of unrecorded species should be based on a single specimen whether it be a
male or female and the specimen is to be referred as ‘holotype’
• The opposite sex specimen which is described along with the holotype is termed as allotype.
• The other specimens of the species kept along with the holotype and allotype are called paratypes
• The names are to be given in Latin. The authors name in full should be written at the end of species name
without any punctuation.
•The generic name has to be a simple or compound word. The supraspecific categories like tribe, sub family,
family and superfamily are denoted by the endings -ni, -inae, -idea and – oides respectively.

• The underlying principle of International code of Zoological nomenclature is law of priority. i.e the first
published name remains in official records while all the subsequently published names go as synonyms.
• If the same name is given by the different scientists to the different organisms, it is called Homonymy.
•All such cases are referred to International commission on Zoological nomenclature which settles such
confusion.
Scientific Nomenclature:
Nomenclature- It is the scientific naming of living things based on the guidelines and rules of International
code of zoological nomenclature (ICZN). (Nomen= name, Calare= to call) means call by name.
Bionomial Nomenclature (1758) - Naming of living beings including insects in their classification by two
names. Carl Van Linneaus was the first to use this system of naming of insects and is called as father of
binomial nomenclature.
Ex: Helicoverpa armigera, Bombyx mori
Trinomial nomenclature - Using three names for a single organism is called as trinomial nomenclature.
Wherein sub species name is also added to the genus and species name.
Ex: Apis cerana indica, Atherigona varia soccata, Amrasca biguttella biguttella.

Basis for naming the species / genera:
1. Based on the host plant:
Ex: Sitophilus oryzae – rice weevil
Thrips tabaci – Tobacoo
2. Based on the locality:
Ex: Callasobruchus chinensis – pulse beetle
Antheraea assamensis – Muga silkworm
3. Based on the morphological characters of insect:
Ex: Oryctus rhinoceros – coconut rhinoceros beetle
4. Based on the authors:
Ex: Aceria channabasanne
Colemenia spheneroids
BIOTYPE: A group of organisms having the same or nearly the same genotype, such as a particular strain of an
insect species.

Taxonomic Units:
• Linneaus published a series of books containing the names of the plants and animals. Among them 10th
Edition “Systema Nature” published during 1758 in which he has recognized seven taxonomic units.
• The hierarchy or the systematic arrangement of these units in the order is called Linneaus hierarchy.
The units of Linnaeus hierarchy are-
1. Kingdom
2. Phylum – subphylum
3. Class – sub class
4. Order – sub order
5. Family – super family – sub family – Tribe
6. Genus – sub genus
7. Species – sub species

Guidelines for Binomial Nomenclature of insects based on International Code of Zoological
Nomenclature:
 Scientific name of the organism should be in Latinized or Italicized
 The taxonomic units should have specific ending
a) Super family- oidea (Apoidea)
b) Family – idea (Noctuidae)
c) sub family – inae (Apinae)
d) Tribe – ini (Xylocopini)
e) sub tribe- ina (Musina)
Ex: Muscaoidea –super family
Muscidae – family
Muscinae – sub family
Muscini – tribe
Musina – sub tribe
Musca – genus
 The procedure scientific naming of insects should be same throughout the world.
The genus name should start with a capital letter and a species name with a small letter Ex: Helicoverpa
armigera, Bombyx mori

 Holotype- Those specimens which are collected and described from a locality for the first time and deposited
in the same place. Holotype is the key to the name of species and settles questions in connection with the name.
The insect specimens from which the published description of species are drawn are called as types, they are of
various catageries and have special names.
 Monotype- A holotype based on a single specimen
 Paratype- All other specimens of his species before him at the time of his original publication of the name
become paratype. Paratype will have little importance to nomenclature.
 Locotype- when original collection becomes old or lost then a fresh collection is made from the same original
locality is called as locotype.
 Syntype / cotype- Every specimen in a type series in which no holotype was designated
 Lecotype- One of the series of syntypes which subsequent to the publication of original description selected
and designated through publication to serve as the type.
 Neotype- A specimen selected as type subsequent to the original description in cases where the original types
are known to be destroyed or were suppressed by the commission.
 Allotype- A paratype of the opposite sex to the holotype.

 The person who described the species for the first time would be the author and his or her name should be written at
the end of the scientific name and should not be underlined or italicized Ex: Ceratovacuna lanigera Zehntner
 Genus name and species name should be underlined while writing or typing and should be italicized while printing.
 The author name should be placed in bracket when the name is revised by another author and his name should be
written without bracket.
Ex: Taeniothrips cardamami Ramk
Scirtothrips cardamami (Ramk) Hood
 If the author name is abbreviated, then should have a full stop.
Ex: Spodoptera litura F.;
Bombyx mori L.
Synonym: Two or more names used for the same taxa or insect species. The later name will be the valid name and other
names will become synonym to each other.
Ex: 1. Tryporyza novella = (Scirpophaga novella)
2. Opisina arenosella = ( Nephantis sernopa)
3. Spilarctia obliqua = (Spilosoma obliqua)= (Diacrisia obliqua)
Homonym: The same name is used for two or more taxa or family, tribe or genera or species. This occurs due to lack of
proper publication. The one that is published latter will be the homonym and it is not valid and should be given a new
name to the latter specimen.

 Later, Linnaeus in his 12th Edition of ‘Systema Nature’ added two more orders i.e. Orthoptera and Thysanoptera
Draw backs of Linnaeus classification
1. Failed to separate insects from other Arthropods
2. Aptera of Linnaeus not only included apterygotan orders but also included Myriapoda,
Crustacea (Scorpion and Spiders etc)
3. Included Dragon flies and Damsel flies in Neuroptera
4. Included Dermaptera in Coleoptera order
 In 1831, Latreilla recognised 3 more new orders in addition to the earlier 9 orders with slight modification and he
grouped the insects in two broad headings viz., Aptera and Alata.
Aptera – Thysanura, Parasita (Mallophaga), Siphonaptera
Alata- Coleoptera, Dermaptera, Orthoptera, Hemiptera, Neruoptera, Hymenoptera, Lepidoptera, Diptera, Rhipiptera
(Strepsiptera)

Insect classification:
• At present around 1.5 million insects have been described out of the estimated population of 3.0 million. It is estimated
that > 75% of the known animal species are up to Arthropods and > 90% by class Insecta and > 88% species belongs to
Endopterygota.
• This vast group of insects were classified in many ways by various authors. The main characters that were used for the
classification are Tarsi, Mouth parts, wings, antenna, eyes, metamorphosis, malpighian tubules, chaetotaxy and abdominal
appendages.
• However, the modern classification of insects is based on the wing characters and is termed as alary system of
classification.
• Linnaeus (1758) in his 10th Edition grouped the insects into 7 orders.
1. Aptera
2. Hemiptera
3. Neuroptera
4. Coleoptera
5. Lepidoptera
6. Diptera
7. Hymenoptera

• In 1885, Breuer recognised 16 orders under two divisions i.e. Apterygota and Pterygota.
• He emphasised the need for the natural system of classification by considering nature of wings, mouth parts,
degree of metamorphosis and number of Malpighian tubules.
• Handlirsch (1908) introduced better system of classification and presently it is being followed by many
taxonomists including A.D.Imms. He classified the insects based on the fossils (Paleontlolgical) evidences and
their structure. Accordingly he grouped the insects in 29 orders.
• Later, insect’s orders were modified by many taxonomists,
Essig and Comstock classified to 33 orders
Borror and Delong classified to 27 orders,
Imms classified to 29 orders
Later, Borror and Delong included Phasmida and Dictyoptera in Orthoptera.

Classification of insects: The basic biological unit in the classification is species.
Species: These are a group of individuals which are similar in their structure, capable of interbreeding and
producing fertile off spring, but at the same time reproductively isolated from other groups.
Subspecies: is an aggregate of phenotypically similar populations of a species, inhabiting a geographic
subdivision of the[ range of a species and differing taxonomically from other populations of the species.
Genus: A group of species having some definite similar characters or relationships is called a genus.
Subfamily: is a group of allied genera to form a subfamily
Family is a taxonomic category containing a single genus or a group of genera of common phylogenetic origin
which is separated from related families by a decided gap. Such families showing similar characters form
order.
The classification of animals was first started by Aristotle (384-322BC). Later by Linnaeus who is considered
as the father of the classification of animals and plants, classified insects into only seven orders viz.,
Coleoptera, Hemiptera, Lepidoptera, Neuroptera, Diptera, Hymenoptera and Aptera.

• Jeannel recognized 40 orders
• Brues, Melander and carpenter recognized 27 orders
• Imms and pruthi gave 29 orders
• Essig and Mani listed 33 orders
• Ross 28 orders
• The following is the classification given by Imms which is being followed by most of the taxonomists.
The class Insecta has two subclasses viz., Apterygota and Pterygota.
Apterygota Pterygota
1. Primarily wingless-evolved from wingless ancestors
Winged or secondarily wingless- evolved from
winged ancestors. e.g. Flea, head louse, bed bug.
2. Metamorphosis is totally absent or slight. Present.
3.
Mandibular articulation in head is monocondylic i.e.,
single
Dicondylic i.e., double.
4. Pleural sulcus in thorax is absent. Present.
5. Pregenital abdominal appendages present. Absent.

Sub class 1. Apterygota – orders
1. Thysanura – Thysan = fringed; ura = tail (Bristle tails, Silverfish, firebrats)
2. Diplura- Di = two; ura = tail (Diplurans)
3: Protura- Pro = first; ura = tail (Telson tails or proturans)
4: Collembola – coll = glue; embol = peg/wedge ie. collophore (Spring tails, snow fleas)
Sub class 2: Pterygota – is divided into two division based on the wing development 1. Exopterygota
2. Endopterygota
Character Exopterygota Endopterygota
1. Wing development External Internal
2. Type of metamorphosis
Incomplete(Hemimetabola)
or gradual (Paurametabola)
Complete (Holometabola)
3. Pupal stage Absent Present
4. Immature stage Naiad or Nymph Larva
5. No. of orders 16 9

I. Exopterygota (Insects having simple metamorphosis)
Group I: Paleopteran orders (order 5 and 6)
5. Ephemeroptera – Ephmera = living for a day; ptera = wings (May flies)
6: Odonata – Odon = tooth i.e. teeth like mandibles (Dragon flies & damsel flies)
Group II: Orthopteriod orders (orders 7 to 15)
7: Plecoptera – Pleco = folded wings; ptera = wings (Stone flies) i.e. anal region of the wings are folded at rest
8: Grylloblattodea – Gryll = cricket; blattodea = cockroach (Grylloblattids or rock crawllers)
9: Orthoptera –Ortho = straight; ptera = wings (Locusts, grass hoppers, crickets, mole cricket)
10: Phasmida – Phasama = an appreciation (Walking sticks, leaf insects & stick insects)
11: Dermaptera – Derma = skin; ptera = wings (Ear wigs)
12: Embioptera – Embio = lively; ptera = wings (Web spinners)
13 Dictyoptera – Dictyo = net; ptera= wings (Cockroaches and mantids)
14: Isoptera – Iso = equal; ptera = wings (White ants or termites)
15: Zoraptera – Zor = pure; aptera =wingless (Zorapterans or angel insects)

Group III: Hemipteriod orders ( order 16 to 20)
16: Psocoptera – Psco = rub small; ptera = wings i.e. gnawing habit of insect ( Psocids, book lice)
17: Mallophaga – Mall = wool, phaga = to eat (Bird lice)
18: Siphunculata or Anoplura – Siphanculus = a little tube (Head and body louse)
19: Hemiptera – Hemi = half; ptera = wings (Plant bugs)
20: Thysanoptera – Thysano = fringe; ptera = wings (Thrips)
II. Endopterygota (Insects having complex metamorphosis)
Group IV: Neuropteroid orders (order 21 to 23)
21: Neuroptera – Neuro = nerve; ptera = wings (Ant lions, lace wings)
22: Coleoptera – Coleo = sheath; ptera = wings (Beetles, weevils)
23: Strepsiptera – Strepsi = twisted; ptera = wings (Stylopids)
Group V: Panarpoid orders (order 21 to 28)
24: Mecoptera – Meco = long; ptera = wings (Scorpion flies)
25. Lepidoptera- Lepido = scales; ptera = wings (Moths and butterflies)
26. Trichoptera – Tricho = hairs; ptera = wings (Caddis flies)
27. Diptera – Di = two; ptera = wings (Flies, midges, mosquitoes)
28. Siphonoptera – Siphon = tube; aptera = wingless (Fleas)

Group VI: Hymenopteroid orders
29: Hymenoptera – Hymen = membranous or Hymeno = god of marriage i.e. union of fore and hind wings
by hamuli (Ants, bees, wasps)
• Earlier, Hemiptera was divied in to two suborders - homoptera and heteroptera but recent workers are
treating homoptera as a separate order due to definite characters by which it is differing from hemiptera.
Thus the study of insects comes to 30 orders.
• Recently a new order Mantophasmida (Mantis= Mantodea; Phasma= Phasmatodea – Gladiator) is added
to the insect order.
I) Palaeopteran orders (Neoptera):
1. Wings are stretched side way both at flight and at rest
2. Wings lack jugal area (a lobe like structure at the base of the forewing which overlaps the hindwings
3. They are incapable of folding their wings over the abdomen
4. Wing coupling mechanism is absent
5. Metamorphosis is incomplete

II) Orthopteroid orders (Polyneoptera):
1. The first pair of wings are modified into tegmina
2. Jugal area is well developed
3. Wings will be folded back easily over the abdomen at rest
4. Wing coupling mechanism is absent
5. Forewings are narrow and hindwings are very much enlarged
6. Metamorphosis is incomplete
7. Mouth parts are mandibulate or chewing and biting type
III) Hemipteroid orders (Paraneoptera):
1. Wings lack jugal areas
2. Wings can be folded back on abdomen
3. Metamorphosis may be hemi or holometabolous type
4. Mouth parts are sucking type
IV) Neuropteroid orders
1. Mouth parts are biting type
2. Pupae is exarate Mr. Suresh Jambagi, M.Sc (Agri) Entomology, UAS Dharwad

V) Panorpoid orders
1. Wings arise from a common stalk, hence called as ‘panaorpoid complex’
VI) Hymenopteroid orders
1. Have 2 pairs of membranous wings and wing coupling is present (hamuli)
2. Mouth parts are basically chewing and modified for lapping
3. Most female have well developed ovipositor and in some insects modified for stinging
Organ.
4. Metamorphosis is complete

Insect systematics

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