jib 116 animal diversity assignment

Debbra Marcel JP/8544/13

JIB 116 Animal Diversity: Assignment 1 1/12

MEDICAL IMPORTANCE OF HEXAPODS TO MAN

A. Overview

The use of animal products for medicinal purposes has been well established

since early human history. There have been many studies of animals carried out by the

scientific community around the world. Even though the therapeutic usage of animals

especially the insects and insect products were widely known since early human

civilization, the studies of plants had predominated these highly resourceful groups of

organisms. Nowadays, zootherapists, entomologists and many other scientists are

making more researches & discoveries on animal and the animal based products after

realizing that these groups of organisms contribute a lot in human lives including

traditional and the modern medical applications. This assignment will review some of

the hexapods that medically important to man.

B. Introduction

Hexapods are the arthropod animals which belong to the subphylum of

Hexapoda and phylum of Arthropoda. Placed together with crustaceans in clade

Pancrustacea, hexapods are mainly characterized by the body structure with distinct

head, thorax and abdomen which is called as 3 tagmata body parts. This group of

invertebrates have uniramous appendages with six jointed legs; a pair of antennae;

mouthparts modified for different food habits; head of six fused segments; thorax of

three segments & two pairs of wings (sometimes one pair or none); abdomen with

variable separate sexes, usually oviparous (laying eggs); one pair of mandibles, unique



tracheal system and Malphigian tubules. Traditionally, there are two classes belong to

the subphylum of Hexapoda, namely Entognatha and Ectognatha (or Insecta).

Entognatha (Gr. entos, within, inside + gnathous, jaws) means the base of the

animal mouthparts lies within the head capsules, and mandibles have only one

articulation. There are three orders of arthropods belong to the class of Entognatha

namely Collembola, Protura and Diplura. Entognathans are mainly characterized by

their tiny size and commonly inhabit soils or dark/damp places. These arthropods are

wingless; legs have been lost from the abdomen and undergo direct development.

Ectognatha (Gr. ecto, outside + gnathous, jaws) or Insecta (L. insectus, cut into)

means the base of the mouthparts exposed and exiting the head capsule, and

mandibles usually have two regions of articulation. There are two subclasses of insects

namely Apterygota and Pterygota. The order of Thysanura placed under the subclass

of Apterygota. Meanwhile, there are two infraclasses namely Paleoptera and Neoptera

placed under the subclass of Pterygota and more than twenty orders of insects

described under them. Insects are the most diverse and abundant of all groups of

arthropods and other animals combined. They can be found almost everywhere in the

world due to their highly adaptable nature and power of flight. Insects’ features and

characteristics are also very diverse. This group of arthropods mainly bears two pairs of

wings on their thorax although some have one pair; and some are wingless. Their

feeding habits include herbivorous, saprophagous, predaceous and parasitic. Almost all

insects undergo metamorphosis and the growth processes are hormonally controlled.



C. Discussion: The medical importance of hexapods to man

Since ancient times, animals have been used as medical sources to

human. The World Health Organization (WHO) estimated about 80% of the world’s

population which is more than six billion of people rely primarily on animal and plant-

based medicines (WHO, 1986). Different places in the world have their own way of

applying animals and animal based products to treat diseases and improve health.

Hexapods particularly insects are the most common animals used in the traditional

medication. Medically, the entognathans have less known for their importance due to

their miniature sizes and rarely encountered by human. On the other hand, insects play

important roles to human welfare, particularly in crops pollination. In medical term,

insects and insect based products have been used by many societies throughout

histories from traditional to the modern applications. Thus, with the technology

expansion, these types of organisms continue to be studied and applied in modern

science.

Following are some of the hexapods that medically important to man;

Honey Bee

Honey bees are a type of hexapods that belong to the order of Hymenoptera,

under the infraclass of Neoptera. These hymenopterans have two pairs of membranous

wings; mobile head; chewing or suckling mouthparts; posterior stinging on females;

undergo complete metamorphosis; and are very social in nature. Among the most well

known worldwide distributed honey bees in beekeeping field are Apis mellifera, Apis

cerana, Apis indica and Apis dorsata due to their contributions and high quality

products. Honey bees are mainly recognized by golden and black stripes on their body.



There are three main categories of bees namely drone (male), worker (sexually

undeveloped female) and queen (egg producer/manufacturer). Basically, there is only

one queen in a bee hive which can lay about 1000 of eggs per day. The male bees are

mainly to mate with queen to produce offspring and workers are the most productive

and beneficial honey bees. According to U. Arı Drg. Kasım (2012), the uses of honey

bee products of all honey bee species for therapeutic purposes (Apitherapy) is well

established since ancient Egyptian times and are effective against wide range of

ailments, from arthritis and chronic pain to multiple sclerosis and cancer.

Honey is a liquid substance produced by the worker bees to feed on the larvae in

the bee hive. Famously known as natural taste enhancer, honey is also contains

multiple chemical compounds that are capable of enhancing the immune system. This

tasty liquid is rich with antioxidant, antibacterial, antiviral and antifungal properties.

Recent research found that the use of multi-floral wild honey obtained from the

Malaysian jungle called Tualang Honey has the potential to prevent the acute

respiratory symptoms such as cough, rhinitis, sore throat and fever besides soothing

external sores and gastric inflammation just like the widely known manuka honey.

Propolis is the sticky resinous product collected by honey bees from plants and

has been used as folk medicine since ancient times. In the past ten years, the

immunoregulatory and anti-inflammatory properties of propolis have been published in

many scientific journals. The active compounds in propolis exhibit variable biological

activities include antibacterial, antiviral, fungicidal, antioxidant, anti-inflammatory,

antitumor, antihelmintic, antifungal and painkilling activity. It is also frequently used for

toothache and gum disease, sore throats, chest infections and also stimulating the



immune system. The polyphenol compounds of propolis are also capable of inhibiting

lipoprotein oxidation thus might be an important step in preventing atherosclerosis.

Bee pollen is one of the richest and purest natural foods ever discovered. This

natural product from flowering plants has incredible nutritional and medicinal values.

The type of plants where the workers gathered the pollen from determined the chemical

composition of bee pollen. This natural elixir rejuvenates human body, stimulates the

organ and gland system, enhance vitality and promote a longer lifespan. Taken orally

as a protein rich nutritional supplement, bee pollen also used to enhance energy,

memory and performance; prevent hay fever; stimulate metabolic functions and

strengthens the cardiovascular and respiratory systems.

Royal jelly is a whitish liquid secreted from the salivary glands of worker bees.

This highly nutritious product is serves as food for the young larvae and as the only food

for the larvae that will develop into queen bees. For human, it can be taken extensively

to promote energy and good health; and improve skin complexion by promoting the

collagen production. It contains mixture of vitamins, minerals, proteins and fatty acids

and known to have various pharmacological effects include antimicrobial, antitumor,

antihypertensive and several more. This heat stable product also has insulin-like action;

neurological and estrogenic effects on the lipid profile; antifatigue effect; exhibit

immunomodulatory and contains globulinic acid which increase resistance bacteria and

viruses. Scientists also suggest that royal jelly can be used as ointment in the treatment

for diabetic patients.

Bee venom which can only be found in the workers’ ovipositor, can treat a

number of ailments. At least 18 pharmacologically active components have been

described in venom and some people claimed this venom able to relief rheumatism and



arthritis. However, it must be used in small/appropriate dose as honeybee venom is

lethal to humans in high doses (around 600 stings for an adult or 90 for a child) while for

those who are allergic to bee stings even a single sting can be fatal.

Other bee product such as beeswax also has unique characteristics as an inert

coating for certain pharmaceutical preparations or as an ingredient to stabilize

ointments and creams. In addition to that, the honey from stingless bees is also of high

medicinal value.

Picture source: http://en.wikipedia.org/wiki/Honey Picture source: http://linuxfocus.org/~guido/med/propolis/

Pis. source: http://keepingbee.org/bee-pollen-

supplements/bee-pollen-supplements2/ Pic. source: http://en.wikipedia.org/wiki/Royal_jelly

Figure 3: Bee carrying pollen Figure 4: Developing queen

larvae in royal jelly

Figure 1: Honey in honey comb Figure 2: Raw propolis



Silkworm

Like honey bees, the moths have separate sexes and undergo complete

metamorphosis. Moth belongs to the order of Lepidoptera, family of Bombycidae and

species of Bombyx mori Linnaeus. Silkworm is a larva of the domesticated moth which

have chewing mandibles for plant eating purpose. The adult stage of this hexapod has

two pairs of membranous wings covered with overlapping scale and a suckling tube

which coiled when not in use. Interestingly, the substrate of mulberry tree leaves which

are the main diet of the silkworms enables these organisms produce a high value

protein product, silk. A silkworm has two specialized glands that produce liquid silk and

constitute about a quarter of the worm mass.

Silkworms have been used extensively as natural medicine in the traditional

Chinese medical system. Bombyx Batryticatus which is derived from a larva of Bombyx

mori L. silkworm that infected with Beauveria bassiana (Bals.) Vuillant. (parasitic fungus

that infect arthropod) is used as one of the liver calming and wind-extinguishing herbs.

The extract of Bombyx Batryticatus is well-known for its anti-hyperglycemic effect and

perform therapeutic actions by extinguishing winds; dispels phlegm; stop tremors and

convulsion; stops pain (headache, red eyes, sore and swollen throat and toothache);

eliminate toxins and dissipates nodules; and relieve itching. A study by W.L. Li et al.

(2004) found the numerous bioactive compounds in Chinese medicinal herbs which

include Bombyx Batryticatus, performed a good clinical practice and is showing a bright

future in the therapy of diabetes mellitus and its complications. The conjugated linoleic

acid (CLA) obtained from this worm may have a biological activity for anti-diabetes and



some alkaloid were also reported to have the possibility of preventing the onset of

diabetes and obesity.

The silk thread that produced by silkworm consists of two types of proteins, silk

sericin and fibroin. Sericin is a protective cover of silk and this protein absorbs and

release moisture easily besides inhibit the activity of tyrosine kinase (an enzyme that

involves in many cellular functions). Sericin has been widely applied in pharmaceuticals

and cosmetics such as wound healing, bio-adhesive moisturizing, anti-wrinkle, anti-

aging, antioxidant, antibacterial and UV resistant. For the sericin-free silk fibre,

modification with gelatin and cross-linking agent demonstrated by Liu et al. (2007)

shows superior mechanical properties and lower inflammatory potential which make

them a promising candidate for ligament tissue engineering applications.

Fibroin, which is another protein content of silk, is a structural polymer

possessing unique physical properties including good biocompatibility and has been

established to be precious material for skin and vascular graft biomedical engineering. It

is known for wound dressing by providing moist environment; facilitate re-

epitheliazation; re-modeling of connective tissues and collagenization.

Picture source:http://www.hiroshima-.ac.jp/en/

top/ kenkyu/now/no18/

Pic. source: http://thewormlady.ca/silkworm-life-

cycle.php

Figure 5: The cross section of silk

thread

Figure 6: Bombyx mori from larva

to adult



Flies

Other medically important hexapods listed here are flies (plural; fly singular).

Flies belong to the order of Diptera. These type of arthropod have single pair of

membranous and narrow wings, where the hind wings reduced to inconspicuous

balancers; suckling mouthparts or adapted for sponging, lapping, or piercing; legless

larvae (maggots). Dipterans include crane flies, mosquitos, moth flies, midges, fruit

flies, flesh flies, house flies, blow flies and many more. Like honey bees and moths, flies

undergo complete metamorphosis.

Flies have been widely used in Maggot Debridement Therapy (MDT) in the USA

since 1930 and Malaysia is the first to conduct MDT research in South East Asia region.

Maggot debridement therapy (MDT) is a form of therapeutic wound treatment utilizing

maggots of certain blowfly species to remove non-vitalized tissue, pus, slough and

metabolic wastes on the wound (Hebda & Lo, 2001). The core beneficial effects of

maggot therapy on wound are; debridement, cleansing, disinfection and enhance

healing of indolent wounds, many of which have previously failed to respond in

conventional treatment. The maggot (larva of fly) of Lucilia cuprina, secrete a rich soup

of digestive enzymes while feeding on the necrotic tissues. Maggots also possess a

pair mandible which assists the larva locomotion and attachment to tissue. Thus, the

secretion of powerful proteolytic enzymes and the mechanical actions of the mandibles

may be the secret of the tissue debridement.

Like other related insects, flies also have been used as genetic models for

several human diseases and aging research since few decades ago. Fruit flies for

instance, used as a genetic organism due to the dipteran’s short life cycle (about two

weeks), very prolific and have four pairs of chromosomes. Drosophila melanogaster



(fruit fly) is one of the most common genetic model organism used to examine complex

biological engineering. Interestingly, 75% of known human disease genes (e.g

Parkinson's, Huntington's, spinocerebellar ataxia and Alzheimer's disease) have a

recognizable match in the genome of fruit flies and the protein sequences of fly have

50% mammalian homologs. With this respect, flies like Drosophila sp. suitable to be

used as tools to study several human diseases; mechanisms underlying aging and

oxidative stress, environmental and genetic manipulations that alter life span; immunity;

diabetes and cancer; as well as drug abuse.

Flies also play an important role in forensic entomology (the application and

study of insects and other arthropods for the use of criminal investigation to determine

the post mortem interval i.e the time of death). A review of forensic specimens received

by Institute for Medical Research (IMR) from 1972-2002 found eighteen species of

cyclorrphaga flies predominated by Chrysomya sp. as the most common dipterans

found on human cadavers. This analysis revealed several important observations

which include a large number of flies attracted to human cadavers under tropical

condition, reflected the diversity of carrion in Malaysia; and the presence of a particular

fly species revealed information on the ecology of the crime scene.

Pic. source: http://en.wikipedia.org/wiki/Maggot_therapy

Pic. source: http://en. wikipedia. org/wiki/Drosophila_melanogaster

Figure 7: A wound cleaned by maggot

(myasis)

Figure 8: Drosophila melanogaster,

useful model for human genetic studies



D. Conclusion

The full impacts of insects and other hexapods on human health and welfare are

almost impossible to be measured. Studies have found that the three insects listed in

this assignment are proven to be medically important to man. However, as many other

insects may treat wide range of illnesses and injuries, some others may also be harmful

to man. Therefore, the continuation of study about medical as well as other benefits of

hexapods is crucial in order to make us more understand and appreciate these six-

legged arthropods. As a result, these efforts will certainly promote the sustainability

and well-being of man.

E. References

Campbell, N.A., & Reece, J.B. 2008. Biology. 6th ed. San Francisco (CA): Benjamin

Cummings. pp. 662-670

Chen, J.K., Chen, T.T. 2004. Chinese Medical Herbology and Pharmacology. City of

Industry, CA USA. Art of Medicine Press, Inc. p. 1336.

Hebda, P.A. & Lo, C.Y. 2001. The effect of acrive ingredients of standard debriding

agents – Papain and collagenase – on digestion of native and denatured

collagenous substrates, fibrin and elastin. Wounds 13(5): 190-19

Hickman, C.P., Robert, L.S., Keen, S.L., Eisenhour, D.J., Larson, A., I’Anson, H. 2013.

Integrated Principles of Zoology. 15th ed. Singapore: McGraw-Hill Education,

International Edition. pp. 444-471



Lee, H.L., Krishnasamy, M., Abdullah, A.G., Jeffery, J. 2004. Review of forensically

important entomological specimens in the period of 1972 - 2002. Tropical

Biomedicine. 21(2): 69-75.

Liu, H., Ge, z., Wang, Y., Toh, S.L., Sutthikhum, V., Goh, James C. H. 2007.

Modification of sericin-free silk fibers for ligament tissue engineering application.

Journal of Biomedical Materials Research Part B: Applied Biomaterials. Vol. 82B,

Issue 1. pp. 129–138.

Uludağ Arıcılık Dergisi Kasım. 2012. Medical Importance of Bee Products. Uludag Bee

Journal November. 12 (4): pp. 136-146

WHO/ IUCN/ WWF. 1986. Guidelines on Conservation of Medicinal Plants. WWF,

Switzerland. Available from:

http://www.ncarboretum.org/assets/File/PDFs/Research/s7150e.pdf

W.L. Li., H.C. Zheng, J. Bukuru, N. De Kimpe. 2004. Natural medicines used in the

traditional Chinese medical system for therapy of diabetes mellitus. Journal of

Ethnopharmacology. 92 (2004): pp. 1–21

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PUSAT PENGAJIAN JARAK JAUH,

UNIVERSITI SAINS MALAYSIA (USM),

11800 PULAU PINANG

(U/P: BAHAGIAN PENERIMAAN TUGASAN)

DEBBRA MARCEL,

VETERINARY RESEARCH INSTITUTE,

59, JLN SULTAN AZLAN SHAH,

31400 IPOH, PERAK