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The University of Zambia

School of veterinary medicine

Department of paraclinical studies

Name: Musalo Brian

Computer #: 10008047

Course code: VMP-4400

Lab: Identification of ticks and mites

Attention: Mr.chota

Date: 10/03/14

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Title: identification of insects

Aim: to identify insects of the orders Diptera, Siphonaptera, Phthiraptera and Hemiptera of

veterinary and medical importance.

INTRODUCTION

The order Diptera also known as true flies are one of the most diverse orders of insects both

morphologically & biologically. The order name means ‘two-winged’ and refers to the fact

that the hind pair of wings is greatly modified and reduced. This order has over 120,000 species

worldwide. Although flies with medical and veterinary significance constitute only a small

fraction of these numbers, their diversity is impressive, ranging from mosquitoes, larvae that

parasitize various animals, and species that help to decompose carrion or feces. No other

group of insects has much impact on human and animal health as do the Diptera (Mullen G. &

Durden L. 2002).

The order Siphonaptera are fleas. These are morphologically unique ectoparasites that are

unlikely to be confused with any other arthropods. They are a monophyletic group that has

evolutionary ties with the mecopteroid insects order mecoptera and diptera. Fleas evolved

from winged ancestors during the late Jurassic or early cretaceous period 125-150 million years

ago. As a group, they have principally evolved as parasites of mammals on 94% of known

species feed, representing 15 families and more than 200 genera of fleas. The remaining 6%,

representing 5 families and 25 genera, are ectoparasites of birds (Mullen G. & Durden L. 2002).

This is an appropriate appellation for these secondarily wingless insects whose mouthparts

are adapted for piercing skin and sucking blood (http://www.cals.ncsu.edu/siphonaptera).

The order Hemiptera includes all of the insects known as true bugs. Hemiptera are

characterized as soft-bodied insects with piercing and sucking mouthparts and, usually, two

pairs of wings. The order traditionally is divided into two major divisions: the Heteroptera and

the Homoptera. The name Hemiptera means ‘half wings’ and is derived from the members of

the Heteroptera (different wings), most of which have fore wings called Hemelytra. They are

composed of the corium and clavus and a transparent, filmy distal portion as well as the

membrane, hence the idea of a half wing. The hind wings are completely membranous. The

difference in texture between the fore and hind wings in the heteropterans give this group its

name. The true bugs have about 90,000 species worldwide and constitutes the largest

exopterygote order of insects (Mullen G. & Durden L 2002).

The order Phthiraptera are lice. These are a menace to humans, pets, and livestock, not only

because of their blood-feeding or chewing habits, but also because of their ability to transmit

pathogens. The human body louse has been indirectly responsible for influencing human

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history through its ability to transmit the causative agent of typhus. However, most of the

3200 known species of lice are ectoparasites of wild birds or mammals and have no known

medical or veterinary importance. The order Phthiraptera is divided into two suborders:

Anoplura (sucking lice) & Mallophaga (chewing or biting lice). All members of the Anoplura

are obligate, hematophagous ectoparasites of placental mammals, whereas the more diverse

Mallophaga include species that are obligate associates of birds, marsupials and placental

mammals. Although certain chewing lice imbibe blood, most species ingest host feather, fur,

skin, or skin products. Because of the different feeding strategies of the two groups, the blood

feeding Anoplura are far more important than the Mallophaga in transmitting pathogens to

their hosts (Mullen G. & Durden L. 2002).

MATERIAL

Material:

Microscopes

Glass slide

Cover slip

70% preservative alcohol

Specimens:

Diptera

Nematocera: (mosquitoes-adult, larvae and pupa)

Brachycera- Tabanus species (adult)

Cyclorrhapha: (house fly-Musca domestica, Tsetse fly (glossina spp), stomoxys (stable

fly))

Phthiraptera

Mallophaga: (Manacanthus spp)

Anoplura: (Haematopinus suis)

Siphonaptera

Ctenocephalides felis

Ctenocephalides canis

Echinophaga gallinacean

Hemiptera

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Triatoma infestans

Cimex spp

PROCEDURE

All the provided specimens were observed grossly and microscopically and special/unique

features that differentiate and help in the classification and identification of these insects on

each specimen were observed

RESULTS

Observations Characteristics

Sub-order: Nematocera

Order: Diptera

• Suborder of elongate flies with

thin, segmented antennae (more

than 6) & plumose in males, long

and slender proboscis, wings long

and narrow, mostly aquatic larvae,

mostly consist of mosquitoes and

midges

• Have small spherical heads and long

legs

• Comprise families simuliidae,

Anophilinae and culicinae

Mouthparts:

piercing-sucking (biting flies)

sponging (house fly), some reduced

or non-functional

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Sub-order: Brachycera

Species: Tabanus

Tabanus Sp have cutting and

lapping mouth parts

maggots have mouth hooks

Wings:

One pair (two) wings on mesothorax, rearely absent. halteres of varying size on metathorax

adults

2 wings- halteres on mesothorax

Characteristic body shape of three

distinct body regions and small

number abdominal segments.

antennae reduced to hair or very

feathery (=plumose) in males

larvae

maggot-like with no body features

except mouth hooks

pupa: oval with tough exoskeleton

covering (=puparium)

Observations Characteristics

Sub-order: Cyclorrhapha

Species(spp): housefly-Musca domestica

Order: Diptera

Spp. M. domestica

Common housefly

Has sponging mouth parts adapted for imbibing liquid food

Its antenna has the 3rd segment bearing an arista which bilaterally plumose

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Species: tsetse fly-Glossina spp.

Species: tsetse fly-Glossina spp.

All belong to genus Glossina.

Commonly known as tsetse flies

Robust flies with various shades of brown, from yellowish to blackish-brown.

Both male and female haematophagus (male and female distinguished by presence of hypopygium on ventral posterior surface in male)

Species: Stable fly-Stomoxys spp

Similar to Musca domestica abdomen is shorter and broader than that of a housefly & has 3 dark spots on each of the 2nd & 3rd segments

Proboscis is prominent

They are swift fliers but do not travel long distances

Both male and female haematophagus

Species: Stable fly-Stomoxys spp

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The main landmarks of flea external morphology

Order: Siphonaptera

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Comparative feature

Observations Characteristics

Sub-order: Ctenocephalides felis

Order: Siphonaptera

Commonly known as fleas

• Comparative feature:

- In C. felis the first tooth on the

genocomb is as long as the second

but in C. canis, the first tooth on the

genocomb is half of the length of the

second tooth

- C. canis adults has a more bluntly

rounded head than C. felis

Immature

Body vermiform (maggot-like),

sparsely covered with hairs

Head reduced, eyeless, mouthparts

mandibulate

Adults

Body bilaterally flattened

Mouthparts suctorial (haustellate)

Large bristles (ctenidia) often present

on head or thorax (genal and

pronotal combs)

Hind femur enlarged, adapted for

jumping

Sub-order: Ctenocephalides canis

Sub-order: Echidnophaga gallinacean

• Echidnophadga gallinacean

- Has angular head

- Ctenidia are absent

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Observations Characteristics

Sub-order: Mallophaga

Species (spp): Manacanthus spp

Order: Phthiraptera

Commonly known as lice

are wingless

Permanent, obligatory ecto-

parasites spending their entire life

cycle on the host

Generally host specific and limited to

a single host species or closely

related hosts

• Lice of medical and veterinary

significance belong to the suborders

– Anoplura (sucking lice) and

– Mallophaga (biting/chewing

lice)

Mouthparts:

chewing in biting & bird lice

(Mallophaga)

piercing & sucking in blood feeders

(Anoplura)

Wings:

none

Body characteristics:

body flattened top to bottom

legs have special claws to grasp host

Sub-order: Anoplura

Species(spp): Haematopinus suis

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Observations Characteristics

Species(spp): Cimex spp

Order: Hemiptera

o Possess two pairs of wings

o Hemi=one half, ptera=wing, anterior

pair of wings most often of harder

consistency than the posterior pair, or

apical portion of first pair wing

membranous and remainder hardened.

o True bugs, aphids, leafhoppers, cicadas

o Have sucking and piercing mouthparts,

majority suck plant juices

o Two families of medical/veterinary

significance: Cimicidae and Reduviidae

(blood-suckers).

Mouthparts:

piercing - sucking from front of head

Wings:

2 pr. - 1st pair (mesothoracic) are basal half hardened & tough with outer half membranous = (hemelytra) while hind pair are only membranous

Body characteristics:

oval or squat body shape;

piercing-sucking mouthparts from front of head;

4/5" long segmented antennae, large eyes, long legs; wings (in adult)

Species(spp): Triatoma infestans

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DISCUSSION

The order Diptera is the most important for veterinary entomologists, literally the means ‘two-

winged’ and all adults have two wings with the exception of certain aberrant forms in the

hippoboscidae (genus melophagus), (Whitlock J.H, 1960). Diptera order is divided into three

suborders, Brachycera, Nematocera and Cyclorrhapha.

The order Nematocera (thread-horns) are a suborder of elongated flies with thin,

segmented antennae and mostly aquatic larvae, consisting of the mosquitoes, crane flies,

gnats, and midges. Nematocera are typically characterized by filamentous, multi-segmented

antennae which may be plumose in some males. Nematocera is a paraphyletic suborder,

because one of its constituent families (Anisopodidae) is apparently a sister taxon to the

entire suborder Brachycera. Examples of the Nematocera include the mosquitoes (Culicidae),

crane flies (Tipulidae) and black flies (Simuliidae). Many of the remaining families (especially

Mycetophilidae, Anisopodidae and Sciaridae), are called gnats, while others (especially

Chironomidae, Cecidomyiidae and Ceratopogonidae) are called midges. The larvae are mostly

aquatic and have distinct heads with mouthparts that may be modified for filter feeding. The

pupae are orthorrhaphous (meaning adults emerge from the pupa through a straight seam in

the pupal cuticle). The bodies and legs of the adults are usually elongate, and these flies often

have relatively long abdomens. Many species form mating swarms of males, and in some of

these, competition for females is extreme. Although many species (as larvae) have a strong

association with water, even within a single family there may be a trend toward semiaquatic

and terrestrial habitats (Wikipedia, 2014).

Species of the genus Tabanus are the largest of the Tabanidae. Their wings are usually clear.

The antennal flagellum is composed of five segments, with the first segment of flagellum

bearing a horn-like projection. Stomoxys spp, Musca domestica and Glossina spp belong to the

suborder Cyclorrhapha. These differ in that Stomoxys have the abdomen that is shorter and

broader than that of Musca domestica and is also grey with three dark spots on the second

and third abdominal segments. The projecting proboscis is sufficiently prominent to

distinguish species of this genus from species of Musca. Glossina is the sole genus in the family

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Glossinidae, species which are known as Tsetse flies. Tsetse is a small distinct genus of 22

species, which feed exclusively on the blood of vertebrates (Veterinary Entomology, 1997).

The order Siphonaptera are fleas. These are morphologically unique ectoparasites that are

unlikely to be confused with any other arthropods. They are a monophyletic group that has

evolutionary ties with the mecopteroid insects order mecoptera and diptera. The order

Siphonaptera has Echidnophadga gallinacean, Ctenocephalides felis and Ctenocephalides

canis were the species looked at in this practical, these being the cat and dog fleas

respectively. They both have the genal and pronotal Ctenidia. In C. felis the first tooth of the

genal comb is as long as the second whereas in C. canis the first tooth of the genal comb is

shorter than the second. In Echidnophadga gallinacean spp, after fertilization the female

burrows into the skin of the fowl, usually on the comb and wattles of birds, resulting in the

formation of nodules in which the eggs are laid. Hatching occurs within the nodules, and the

larvae drop to the ground to complete development. The skin over the nodules often

becomes ulcerated, and young birds may be killed by heavy infections. Echidnophadga also

attacks mammals, principally dogs, the nodules being for-med around the eyes and between

the toes.

The order Hemiptera includes all of the insects known as true bugs. Hemiptera are

characterized as soft-bodied insects with piercing and sucking mouthparts and, usually, two

pairs of wings. Cimex causes annoyance in human dwellings, severe irritation and anaemia in

poultry. The female lays eggs in the dark crevices and the larvae hatch after 3-14 days at

favourable conditions. Then after the five nymphal stages, adult develop within 8-13 weeks at

favourable conditions. Drugs such as lindane chlordane and dieldrin are effective in bedbug

control by spraying and dusting. Triatomidae in which Triatoma infestans belongs transmits

Trypanosoma cruzi, the cause of human trypanosomiasis in South America. Control of

Triatoma is difficult because these bugs fly long distances.

The order Phthiraptera are lice. These are a menace to humans, pets, and livestock, not only

because of their blood-feeding or chewing habits, but also because of their ability to transmit

pathogens. The chicken body louse, Menacanthus stramineus often causes significant skin

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irritation and reddening through its persistent feeding. Occasionally the skin or soft quills

bleed from their gnawing and scraping action, with the lice readily imbibing the resultant

blood. Large infestations of chicken body lice, shaft lice, and other poultry lice may be

injurious to the host by causing feather loss, lameness, low weight gains, inferior laying

capacity, or even death (Mullen and Durden, 2002). Pediculosis is the infections caused by lice

infestations. Organophosphates insecticides are used for treatment and control. Pour-on or

spot on synthetic Pyrethroids, such as Cypermethrin, or parenteral Ivermectin are used.

Ivermectin is ideal and more effective against sucking lice.

CONCLUSION

Mosquitoes (adult, larvae and pupae) in the suborder Nematocera, Tabanus spp in the

suborder Brachycera, Musca domestica, Glossina spp and Stomoxys spp in the suborder

Cyclorrhapha; true bugs (e.g. Triatoma infestans) and Cimex spp of the Hemiptera;

Echidinophaga gallinacean, Tunga penetrans, Ctenocephalide felis & Ctenocephalide canis in the

order Siphonaptera and Haematopinus suis and Menacanthus spp in order Phthiraptera were

identified.

REFERENCES

Mullen G. & Durden L. (2002), Medical and Veterinary Entomology, Academic press,

Elsevier, San Diego, California, USA.

Wall R. Shearer D., (1997) Veterinary Entomology, 1st edition, chapman & hall press, New

York, USA.

Whitlock J.H, (1960), Diagnosis of veterinary parasitism, lea & febiger press, Philadelphia,

USA.

http://www.cals.ncsu.edu/course/ent425/library/compendium/siphonaptera.html