Name: Rokeish Rowe

ID #: 18120647

Course: Foundations of Biology 2

Instructor: Mr. C. Foster

Lab Date: March 27, 2014

Lab time: Thursday 3:30-6:30pm

Lab Instructors: Edwina Henry and Lenour Panton

Lab #: 7

Title: Insecta

Aim: To observe external structure of the different insect orders.

Abstract:

The purpose of the Insecta lab was to observe external structure of the different insect orders.

The insects were collected and diagrams were drawn to depict the structure of the organisms and

were recorded as the results. Insects are a class of invertebrates within the arthropod phylum that

have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of

jointed legs, compound eyes and one pair of antennae. They are among the most diverse groups

of animals on the planet, including more than a million described species and representing more

than half of all known living organisms.

Abbreviation:

Denotrophic viviparity: a type of development where eggs hatch within the female insect

and the larvae are nourished until ready to pupate. At this stage the larvae are laid and

pupate immediately.

Aestivation: a period of summer dormancy.

Bivoltine: a species having two broods per year.

Brood parasitism: a form of parasitism whereby the parasite uses another organism to

raise the parasite's offspring rather than the host's own offspring.

Caterpillar: the second stage in the life cycle of butterflies and moths.

Chorion: the outer shell of an insect's egg.

Chrysalis: the third stage in the life cycle of a butterfly or moth.

Cocoon: the protective covering around the pupae or chrysalis of some insects.

Complete metamorphosis: a type of metamorphosis in which an insect goes through four

distinct stages: egg, larva, pupa, imago.

Cremaster: a series of hooks used to attach the pupa of a butterfly or moth to a twig or

other structure.

Introduction:

Orthoptera: Orthoptera is an order of insects with paurometabolous or incomplete

metamorphosis, including the grasshoppers, crickets, cave crickets, Jerusalem crickets, katydids,

weta, lubber, Acrida, and locusts. Many insects in this order produce sound (known as a

"stridulation") by rubbing their wings against each other or their legs, the wings or legs

containing rows of corrugated bumps. The tympanum or ear is located in the front tibia in

crickets, mole crickets, and katydids, and on the first abdominal segment in the grasshoppers and

locusts. These organisms use vibrations to locate other individuals. Orthopterans have a

generally cylindrical body, with hind legs elongated for jumping. They have mandibulate

mouthparts and large compound eyes, and may or may not have ocelli, depending on the species.

The antennae have multiple joints, and are of variable length. The first and third segments of the

thorax are enlarged, while the second segment is much shorter. They have two pairs of wings,

which are held overlapping the abdomen at rest. The forewings, or tegmina, are narrower than

the hindwings and hardened at the base, while the hind wing is membranous, with straight veins

and numerous cross-veins. At rest, the hindwings are held folded fan-like under the forewings.

The final two to three segments of the abdomen are reduced, and have single-segmented cerci.

Lepidoptera: Lepidoptera is a large order of insects that includes moths and butterflies (both

called lepidopterans). It is one of the most widespread and widely recognizable insect orders in

the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and

moth-butterflies. The Lepidoptera show many variations of the basic body structure that have

evolved to gain advantages in lifestyle and distribution. Recent estimates suggest that the order

may have more species than earlier thought, and is among the four most speciose orders, along

with the Hymenoptera, Diptera, and the Coleoptera. Lepidopteran species are characterized by

more than three derived features, some of the most apparent being the scales covering their

bodies and wings, and a proboscis. The scales are modified, flattened "hairs", and give butterflies

and moths their extraordinary variety of colors and patterns. Almost all species have some form

of membranous wings, except for a few that have reduced wings or are wingless. Like most other

insects, butterflies and moths are holometabolous, meaning they undergo complete

metamorphosis. Mating and the laying of eggs are carried out by adults, normally near or on host

plants for the larvae. The larvae are commonly called caterpillars, and are completely different

from their adult moth or butterfly form, having a cylindrical body with a well-developed head,

mandible mouth parts, and from 0 to 11 (usually 8) pairs of prolegs. As they grow, these larvae

will change in appearance, going through a series of stages called instars. Once fully matured,

the larva develops into a pupa, referred to as a chrysalis in the case of butterflies and a cocoon in

the case of moths. A few butterflies and many moth species spin a silk case or cocoon prior to

pupating, while others do not, instead going underground. The Lepidoptera have, over millions

of years, evolved a wide range of wing patterns and coloration ranging from drab moths akin to

the related order Trichoptera, to the brightly colored and complex-patterned

butterflies.Accordingly, this is the most recognized and popular of insect orders with many

people involved in the observation, study, collection, rearing of and commerce in these insects. A

person who collects or studies this order is referred to as a lepidopterist.

Coleoptera: The Coleoptera is an order of insects is commonly called beetles. The word

"coleoptera" is from the Greek koleos, meaning "sheath"; and pteron, meaning "wing", thus

"sheathed wing", because most beetles have two pairs of wings, the front pair, the "elytra", being

hardened and thickened into a sheath-like, or shell-like, protection for the rear pair, and for the

rear part of the beetle's body. The superficial consistency of most beetles' morphology, in

particular their possession of elytra, has long suggested that the Coleoptera are monophyletic, but

growing evidence indicates this is unjustified, there being arguments, for example, in favour of

allocating the current suborder Adephaga their own order, or very likely even more than one.

The Coleoptera include more species than any other order, constituting almost 25% of all known

types of animal life-forms.About 40% of all described insect species are beetles (about 400,000

species), and new species are discovered frequently. Some estimates put the total number of

species, described and undescribed, at as high as 100 million, but a figure of one million is more

widely accepted.The largest taxonomic family is commonly thought to be the Curculionidae (the

weevils or snout beetles), but recently the Staphylinidae (the rove beetles) have claimed this title.

The diversity of beetles is very wide. They are found in all major habitats, except marine and the

polar regions. They have many classes of ecological effects; particular species are adapted to

practically every kind of diet. Some are nonspecialist detritus feeders, breaking down animal and

plant debris; some feed on particular kinds of carrion such as flesh or hide; some feed on wastes

such as dung; some feed on fungi, some on particular species of plants, others on a wide range of

plants. Some are generalist pollen, flower and fruit eaters. Some are predatory, usually on other

invertebrates; some are parasites or parasitoids. Many of the predatory species are important

controls of agricultural pests. For example, beetles in the family Coccinellidae ("ladybirds" or

"ladybugs") consume aphids, scale insects, thrips, and other plant-sucking insects that damage

crops.

Hymenoptera: The Hymenoptera are one of the largest orders of insects, comprising the sawflies,

wasps, bees and ants. Over 150,000 species are recognized, with many more remaining to be

described. The name refers to the wings of the insects, and is derived from the Ancient Greek

ὑμήν (hymen): membrane and πτερόν (pteron): wing. The hind wings are connected to the fore

wings by a series of hooks called hamuli. Females typically have a special ovipositor for

inserting eggs into hosts or otherwise inaccessible places. The ovipositor is often modified into a

stinger. The young develop through holometabolism, (complete metamorphosis) — that is, they

have a worm-like larval stage and an inactive pupal stage before they mature. Hymenoptera

range in size from very small to large insects, and usually have two pairs of wings. Their

mouthparts are adapted for chewing, with well-developed mandibles (ectognathous mouthparts).

Many species have further developed the mouthparts into a lengthy proboscis, with which they

can drink liquids, such as nectar. They have large compound eyes, and typically three simple

eyes, (ocelli). The forward margin of the hind wing bears a number of hooked bristles, or

"hamuli", which lock onto the fore wing, keeping them held together. The smaller species may

have only two or three hamuli on each side, but the largest wasps may have a considerable

number, keeping the wings gripped together especially tightly. Hymenopteran wings have

relatively few veins compared with many other insects, especially in the smaller species.

Mantodea: Mantids have elongate bodies that are specialized for a predatory lifestyle: long front

legs with spines for catching and holding prey, a head that can turn from side to side, and cryptic

coloration for hiding in foliage or flowers. Mantids are most abundant and most diverse in the

tropics; there are only 5 species commonly collected in the United States and 3 of these have

been imported from abroad. Mantids are the only insects that can turn their head from side to

side without moving any other part of the body. Many humans mistakenly interpret this behavior

as a sign of intelligence. A female mantid may eat her mate while he is still linked with her in

copulo. This behavior is probably more common in captivity than in the wild. Most mantids are

cryptically colored to blend with their environment. A pink Malaysian species spends most of its

time hunting for prey on pink orchids. Although mantids usually feed on insect prey, they have

been known to catch and eat small frogs, lizards, and even birds

Blattadia: The Blattaria includes the roaches, from the six-inch tropical roaches of South

America to their small cousins that are probably tiptoeing through your kitchen right now. There

are about 4,000 species worldwide. Blattaria are cursorial (adapted for running) and move

rapidly. They have flattened bodies and their head is concealed from above by their pronotum.

They have two pairs of wings, but in some species the wings are greatly reduced. Cockroaches

are somewhat general feeders. They do have a preference for materials high in fats and starches.

They deposit their eggs in a capsule called an ootheca. Several species invade homes where they

can contaminate food. They have an unpleasant odor and can be very annoying in the home.

Cockroaches go through simple metamorphosis.

Hemiptera: Hemiptera is an order of insects most often known as the true bugs, comprising

around 50,000–80,000 species of cicadas, aphids, planthoppers, leafhoppers, shield bugs, and

others. They range in size from 1 mm (0.04 in) to around 15 cm (6 in), and share a common

arrangement of sucking mouthparts. Sometimes, the name true bugs are applied more narrowly

still to insects of the suborder Heteroptera only. He defining feature of hemipterans is their

possession of mouthparts where the mandibles and maxillae are sheathed within a modified

labium to form a "beak" or "rostrum", called a proboscis, which is capable of piercing tissues

(usually plant tissues) and sucking out the liquids – typically sap. The forewings of Hemiptera

are either entirely membranous, as in the Sternorrhyncha and Auchenorrhyncha, or partially

hardened, as in most Heteroptera. The name "Hemiptera" is from the Greek ἡμι- (hemi; "half")

and πτερόν (pteron; "wing"), referring to the forewings of many heteropterans which are

hardened near the base, but membranous at the ends. Wings modified in this manner are termed

hemelytra (singular: hemelytron), by analogy with the completely hardened elytra of beetles, and

occur only in the suborder Heteroptera. The forewings may be held "roofwise" over the body

(typical of Sternorrhyncha and Auchenorrhyncha), or held flat on the back, with the ends

overlapping (typical of Heteroptera). In all suborders, the hindwings – if present at all – are

entirely membranous and usually shorter than the forewings. The antennae in Hemiptera are

typically five-segmented, although they can still be quite long, and the tarsi of the legs are three-

segmented or shorter.

Materials:

Orthoptera (Grasshopper)

Lepidoptera (Moth)

Coleoptera (Beetle)

Hymenoptera (Wasp)

Mentodia (Preying Mantis)

Blattadae (Cockroach)

Hemiptera (Stink Bug)

Method:

The materials were obtained and diagrams were drawn to depict the structure of the organisms.

Results: See Diagram

Discussion:

Insects are a class of invertebrates within the arthropod phylum that have a chitinous

exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound

eyes and one pair of antennae. They are among the most diverse groups of animals on the planet,

including more than a million described species and representing more than half of all known

living organisms.

Insect vs. Other Animals”

Insects belong to phylum (or sub-category) Arthropoda which is the largest of all the Phylums in

the animal kingdom. Insects are distinguished by the presence of a cutaneous exoskeleton. They

have a hard shell outside and softer more vital parts of the body inside. Most of the insects do not

have a circulatory system. There is a pool of Haemolymph (blood) in which all the internal

organs remain soaked. These organs take in nutrition and air from the surrounding fluid

whenever required

Segmentation:

The head is enclosed in a hard, heavily sclerotized, unsegmented, exoskeletal head capsule, or

epicranium, which contains most of the sensing organs, including the antennae, ocellus or eyes,

and the mouthparts. Of all the insect orders, Orthoptera displays the most features found in other

insects, including the sutures and sclerites. Here, the vertex, or the apex (dorsal region), is

situated between the compound eyes for insects with a hypognathous and opisthognathous head.

In prognathous insects, the vertex is not found between the compound eyes, but rather, where the

ocelli are normally. This is because the primary axis of the head is rotated 90° to become parallel

to the primary axis of the body. In some species, this region is modified and assumes a different

name.

The thorax is a tagma composed of three sections, the prothorax, mesothorax and the metathorax.

The anterior segment, closest to the head, is the prothorax, with the major features being the first

pair of legs and the pronotum. The middle segment is the mesothorax, with the major features

being the second pair of legs and the anterior wings. The third and most posterior segment,

abutting the abdomen, is the metathorax, which features the third pair of legs and the posterior

wings. Each segment is dilineated by an intersegmental suture. Each segment has four basic

regions. The dorsal surface is called the tergum (or notum) to distinguish it from the abdominal

terga. The two lateral regions are called the pleura (singular: pleuron) and the ventral aspect is

called the sternum. In turn, the notum of the prothorax is called the pronotum, the notum for the

mesothorax is called the mesonotum and the notum for the metathorax is called the metanotum.

Continuing with this logic, the mesopleura and metapleura, as well as the mesosternum and

metasternum, are used.

The abdomen: is the largest tagma of the insect, which typically consists of 11–12 segments and

is less strongly sclerotized than the head or thorax. Each segment of the abdomen is represented

by a sclerotized tergum and sternum. Terga are separated from each other and from the adjacent

sterna or pleura by membranes. Spiracles are located in the pleural area. Variation of this ground

plan includes the fusion of terga or terga and sterna to form continuous dorsal or ventral shields

or a conical tube. Some insects bear a sclerite in the pleural area called a laterotergite. Ventral

sclerites are sometimes called laterosternites. During the embryonic stage of many insects and

the postembryonic stage of primitive insects, 11 abdominal segments are present. In modern

insects there is a tendency toward reduction in the number of the abdominal segments, but the

primitive number of 11 is maintained during embryogenesis. Variation in abdominal segment

number is considerable. If the Apterygota are considered to be indicative of the ground plan for

pterygotes, confusion reigns: adult Protura have 12 segments, Collembola have 6. The

orthopteran family Acrididae has 11 segments, and a fossil specimen of Zoraptera has a 10-

segmented abdomen.

Exoskeleton

The insect outer skeleton, the cuticle, is made up of two layers: the epicuticle, which is a thin and

waxy water resistant outer layer and contains no chitin, and a lower layer called the procuticle.

The procuticle is chitinous and much thicker than the epicuticle and has two layers: an outer

layer known as the exocuticle and an inner layer known as the endocuticle. The tough and

flexible endocuticle is built from numerous layers of fibrous chitin and proteins, criss-crossing

each other in a sandwich pattern, while the exocuticle is rigid and hardened. The exocuticle is

greatly reduced in many soft-bodied insects (e.g., caterpillars), especially during their larval

stages.

Insects are the only invertebrates to have developed active flight capability, and this has played

an important role in their success. Their muscles are able to contract multiple times for each

single nerve impulse, allowing the wings to beat faster than would ordinarily be possible. Having

their muscles attached to their exoskeletons is more efficient and allows more muscle

connections; crustaceans also use the same method, though all spiders use hydraulic pressure to

extend their legs, a system inherited from their pre-arthropod ancestors. Unlike insects, though,

most aquatic crustaceans are biomineralized with calcium carbonate extracted from the water.

Economic Importance Of Insects

Useful Insects

Mostly insects are thought to be pestiferous creatures that should be destroyed at all cost. But

there are many beneficial acts performed by insects that are indispensable to man.

Productive insects: Human beings are greatly indebted to certain insects, which supply them

with useful products. Many commercial products produced by insects are indispensable to

modern man. Honey and beewax are produced by the honey bees. Certain scale-insects also

produce wax. The silkworms supply the commercial silk. Lac insects belonging to the family

Coccidae secrete a wax known as shellac. The dyes tannin and cochineal are derived from the

dried bodies of certain scale-insects living on cacti. Pollinators of flowers: The greatest service

rendered to man by his ‘insect friends’ is the pollination of flowers. Cross fertilization or cross

pollination is very necessary for the fertility and the vigour of plants which depend upon certain

insects for this purpose. In some cases special flower developments favour insect visits. Many

insects and flowers are mutually dependent since many insects feed upon the nectar and pollen

grains of the flowers. Among the outstanding pollinators are the bees, wasps, beetles, ants, flies

etc.

Scavengers: The insects feed upon the waste materials such as the dead bodies and debris of

plants and animals, thus preventing decay and obnoxious odours. The common examples of

insect scavengers are the silverfish, termites, housefly, blowfly, maggots, dung beetles, carrion

beetles, fleas, cockroaches and many larvae.

Insects as food: The insects provide an abundant food supply for animals like, frogs, lizards,

snakes fishes, etc. Blue-birds, meadow-larks, and house sparrows depend chiefly on insects.

Moles, shrews, armadillos, and ant eaters live wholly upon small insects. Man consumes many

insects and their larvae, eggs, only accidently with fruits and other foods. The natives of Amazon

valley eat Suab-ants. Termites form favourite food in tropics. Eggs of Coriza femorata are taken

in Mexico, while larvae of Goliath beetle of Africa are a fine food morsel. The Greeks ground

locusts in mortars and made flour of them. American Indians used to dry or smoke the larger

caterpillars and preserve them for later use.

Insects in medicines: The cochineal insects contain carminic acid, coccerin, myrestin, fat and

fatty acids and are used in the treatment of neuralgia, and whooping cough. Blowfly larvae are

use in treating decay of tissues. Canthardin oil made out of blister-beetles, serve as hair restorer.

The body extract of the cocoons of the silk moth, is used for checking profuse menstruation and

in treating leucorrhoea and chronic diarrhea. Bee-venom has been used with some degree of

success in treatment of some forms of arthritis. Bee-venom has also been used in the preparation

of anti-venom to counteract snake bite. Honey is a natural antiseptic which prevents infection if

applied to a wound. It is also applied to cure ulcers. The beewax is used as a base for ointments.

Distribution/Population:

Though the true dimensions of species diversity remain uncertain, estimates range from 1.4 to

1.8 million species. This probably represents less than 20% of all species on Earth, and with only

about 20,000 new species of all organisms being described each year, most species likely will

remain undescribed for many years unless species descriptions increase in rate. About 850,000–

1,000,000 of all described species are insects. Of the 24 orders of insects, four dominate in terms

of numbers of described species, with an estimated 600,000–795,000 species included in

Coleoptera, Diptera, Hymenoptera and Lepidoptera. Almost as many species of beetles have

been named as all other insects added together, or all other noninsects (plants and animals).

Conclusion: The external structures of the different insect orders were observed.

Reference:

Biology by Campbel and Reece 9th edition

A Taxonomy for Learning, Teaching, and Assessing: A Revision of Bloom's Taxonomy of

Educational Objectives by Lorin W. Anderson

http://projectbeak.org/adaptations/internal.htm