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Entomology: SYSTEMATICS 1 Kingdom: Animalia, Phylum: Arthropoda Subphylum: Hexapoda: Class: Insecta:
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Systematics |
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Historical Review The procedure of modern
systematics was begun in 1958 when the Swedish botanist, Linnaeus, published Systema Naturae. it established the binomial system for naming
organisms. The 10th edition of this
publication established Systematics for Zoology. An organism thereafter was given a generic plus a species name. Also permissible under this system are
various interspersed gradations such as subspecies, subfamily, superfamily,
etc. There is never more than one Genus
name; however, there may be synonymous species names. Also, an abbreviation of the name of the
person who described the species is designated as, for example: Genus species Linn. = Linnaeus described the organism in the
Genus as written. Genus species (Linn.) = Linnaeus described the organism, but he
had placed it in a different Genus. Law of Priority.
-- This states that the first name given to a species is preferred if it is
later described under another name.
The later name for the same species is than called a synonym. Common Name System.
-- This is used as a substitute for the names of orders and families, as, for
example, beetles, locusts, etc. It
applies to a segment of an order.
However, scientific names are more valuable in international
discourse. Characters
Used For Classification. -- Three principal
characters that are used for classifying an organism are (1) morphological,
which includes structure of the wings and mouthparts, (2) physiological, such
as metamorphosis, and (3) Paleontological, where there may be fossil data. But the latter is not very extensively
used in classification because insects are not too abundant as fossils
although they were present over 300 million years ago. Periodic
Name Changes. -- Changes in both the
genus and species names of insects are found throughout the literature,
causing some confusion when older references are consulted. Also certain authors may not accept a name
change and will continue to refer to an insect by its older name. A famous example is that of the
cottony-cushion predator, Rodolia (Novius)
cardinalis that startled the entomological world when it was deployed
successfully in biological control.
Present literature may refer to either of the generic names noted
here. -------------------------------------------- Modern
Classification System For Hexapoda Two principal subdivisions are
(1) Apteragota, which are the
primitively wingless forms that never bore wings in antiquity and (2) Pteragota,
which includes all those presently bearing wings or which had wings in
antiquity. The latter is evident from
the vestiges of sclerites (plates) that appear on their pleural regions of
the thorax. Only one order,
Thysanura, is presently assigned to this category. Previously members of the Class Entognatha were classified with the
Insecta, which includes the orders Collembola, Diplura and Protura. The Apteragota
show no metamorphosis (Ametabolous). The Apteragota are further subdivided into
forms with recessed mouthparts (Entotrophi)
and exposed mouthparts (Exotrophi). The genae are responsible for covering the
mouthparts. All Apteragota possess
only one pivot point on the mandibles. The Pteragota
embrace forms that show incomplete metamorphosis (Hemimetabolous)
and complete metamorphosis (Holometabolous and
Paurometabolous). Furthemore, they may be subdivided into
general nameless categories, which take into consideration the presence of
one or two mandibular pivots, with the former being primitive. The primitive venation is one with
numerous crossveins while the more evolved condition is a reduced
venation. A sideward extension of the
wings is more primitive than the more evolved folded wings. Linnaeus described insects in only
seven orders: Hymenoptera,
Coleoptera, Lepidoptera, Diptera, Hemiptera, Aptera and Orthoptera. Subsequently additional orders were
designated as the study of Entomology progressed, until as of 2010 there are
twenty-four (See Orders). ------------------------------------------- Details
of Insect Taxonomic Groups Examples of beneficial species
occur in almost every insect order, and considerable information on
morphology and habits has been assembled.
Therefore, the principal groups of insect parasitoids and predators
provide details that refer to the entire class Insecta. These details are available at <taxnames.htm>. ============= |