Biodiversity

Tuesday, May 09, 2006

MORPHOLOGICAL DIFFERENCES BETWEEN CARTILAGINOUS AND BONY FISH


All fishes are classified as vertebrates organisms. Vertebrates organisms are organisms with the backbone. Fishes breathe in through their gills. Abedon (1997) also says that both cartilaginous and bony fishes belong to the kingdom animalia. Sharks, skates and rays are thought to be the examples of the cartilaginous fishes. They are termed cartilaginous because of the absence of the real bone, but their bodies consist of a cartilage. While on the other side bony fishes are thought to be real fish because they contain bones in their body.

Unlike other types of fishes, cartilaginous fishes have strong jaws. The mouth of the cartilaginous fish is found underside of the head, while the eyes are found on top of the head. Cartilaginous fishes also possess the ''two nostrils which are used for smelling'' (Abedon, 1997). As Shark is one example of the cartilaginous fish, they are unable to see the food while entering their mouth. The skin of the cartilaginous fishes such as the sharks, rays and skates is also compared with the sandpaper, because of its roughness. Five to seven pairs of the external gill openings are also found in the cartilaginous fishes. But ghost sharks have the skin which is smooth and one pair of the external gill openings. Fertilization in cartilaginous fishes is internally.

While on the other side bony fishes are termed true fishes. This is because we are familiar with this type of fish. An example of these fishes includes groper, gurnard and snapper. Unlike cartilaginous fishes, bony fishes have bones and one pair of the external gill openings. Its mouth is also found in the front of the head. Bony fishes also possess a tail fin which is equal in both bottom and top portions.

The brain of the ghost sharks is closely related to that of the birds and mammals (Wikipedia contributors). As compared to that of the bony fish, the brain of the cartilaginous is ten times to that of the bony fish. While the brain size of the bony fish is thought to closely relate to that of the human beings, the reason of having such a big brain is attributed to the much usage of energy.

In conclusion, one can say that both fishes, cartilaginous and bony indicate a huge morphological variety. This is because their structural body is totally different, as one considers that the mouth of the cartilaginous fish is under the head while that of the bony fish is in front of the head the head. Even the cover of their body is different; the cartilaginous fish is covered with a rough skin while on the other side the bony fish is covered with the rough skin but not like the one in the cartilaginous fish.

References:
Abedon, T. S. 1997. Ascent of mammals. [Online]. Available from:
Wikipedia contributors. Chondrichthyes [Internet]. Wikipedia, The Free Encyclopaedia; 2006 May 05, 13:15 UTC [cited May 08]. Available from: http://en.wikipedia.org/wiki/Cartilaginous

Wikipedia contributors. Bony Fish [Internet]. Wikipedia, The Free Encyclopaedia; 2006 May 06, 13: 23 UTC [cited May 08]. Available from:
http://en.wikipedia.org/wiki/Bone


Peter Muvhali
CSIR PTA
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SIGNALS USED BY INSECTS TO ATTRACT A MATE FOR SEXUAL REPRODUCTION

Most of the species have males and females, that mate and reproduce sexually. They reproduce by laying eggs, while in some insects they reproduce by developing embryo which devolop inside the female and are born after a short gestation. And for those species to do reproduction they have to underwent mating period which is different depending on the type of insect’s species. (2)

"During the mating period for many insect they underwent Courtship ritual. Which they perform to show that they are ready for mating, while on the other insect there did not show any sign or attract male,they are often stroked by males. Males use legs or antennae to stroke females for sex".(2)

There is different method that the insect use to attract mating; it can be regarded as mating calls or courtship. Some insects release gland known as pheromones mostly it happens on intraspecific interaction, while intraspecific interaction species release allelochemicals.all this chemical are known as semiochemicals it is used for attraction, repellents and stimulants of male insects species for mating.(1)

These pheromones are unique for each species to know that there is an insect of the same species which is ready for mating, and it is simple for male species to follow the scent trail. Insect can detect the smell from distance. It was suggested that moth insect can detect the scent close to eleven kilometres. (1)

In some species during the arrival at the female territory male secrete the scent for courtship, and it helps females to access the quality and quantity of the male. And most of the scent or pheromones that the male release are the scent from the flowers.

Insect like butterflies use colours and movement for attraction, male butterflies will be attracted by the coloured imitation of females, while other flies also forms a compact swarms that attract the females.(1)

Other species uses sound for attraction, frogs croak and chucks to attract male frogs for mating and bird sing a song for mating calls. Some insect that use sound for attracting males for mating , are Female grasshoppers, crickets and cicadas males.

Envious, happens in every species, most of the organisms that use signals for mating they have different method to protect their sperms from other male some stay with their mated females to guard them preventing her for mating again. They also extend copulation which prevents other males to mate with her in that period. There is completion for mating in species so they have to prevent other to mate with the species that they mate. some species produce chemicals that plugs the vagina of the female after mating and this give her opportunity for her to mate once while other have genital apparatus that push the arriving sperms back out of the way in the female spermathecae. Because most of the species like to have their own product some have the apparatus that they use to remove the sperms of previous males from females. (1)

In general most of the species that cannot undergo courtship they use pheromones and allelochemicals to attract males for mating while other uses sound to indicate that they are ready for mating. So this method of mating call or signals that they use helps the male insect to identify the insect which is ready for mating, different species know signs and smell the scent for attraction of the species of the same group.


Reference

1. Entomology [Internet] updated 2004 [cited 2006- 05- 08] Available from: http://bugs.bio.usyd.edu.au/Entomology/InternalAnatomy/reproduction.html

2. Encyclopedia Smithsonian; Mating Insects, [internet] [cited 2006-05-08] Available from: http://www.si.edu/RESOURCE/FAQ/nmnh/buginfo/mating.htm

Mr Elelwani Muanalo
NISL- Ecological Informatics Student
CSIR Pretoria
Tel: +27 12 841 2133
Fax: +27 12 842 7024.
Email: http://www.blogger.com/emuanalo@csir.co.za
My bloger URL: http://www.emuanalo.blogspot.com/

HOW THE FIRST PLANTS AND ANIMALS EVOLVED AND BECAME DEPENDENT ON EACH OTHER

Plants are the living organisms that grow in the earth and have a stem, leaves and roots. They play an important role in the cycle of nature and without them; there could be no life on the earth. Plants are the primary producers that maintain all life forms or other living organisms on earth. They manufacture their own food during the process of photosynthesis.

Animals refer to any living organisms that are not plant including people. Animals cannot manufacture their own food; they depend on plants both directly and indirectly for their survival, meaning that in order for them to get their food; they have to depend on plants. All animals and the food that they eat can be traced back to plants ( Kazlev, 2002).

During the process of photosynthesis, "plants take energy from the sun and carbon dioxide from the air". They also take water and minerals from the soil and give off water and oxygen. Human beings or animals breathe the oxygen which comes from the plants. Animals and other non producers take part in the process of respiration. Respiration is "the process whereby oxygen is used by organisms to release energy from the food and carbon dioxide is taken out". The process of photosynthesis and respiration help to maintain the natural balance of oxygen, carbon dioxide and water from the earth (Kazlev, 2002).

The leaves of the plants absorb energy from the sun and turn water and carbon dioxide into sugar and starch. "Sugar and Starch provide plants with energy to grow and they also reduce flowers and seed and carry on their other life processes". Most of the animals prefer the leaves of the plants. Plants and animals are complex organisms made up of cells. Plant cells have "thick, rigid walls that consist of cellulose and cells of animals do not have thick as well as rigid walls". Plants need heat from the sun to grow and the climate of the area also plays an important role in the growth or survival of the plants (Kazlev, 2002).

Prokaryotic are the plant fossils known as bacteria. They feed themselves on "the chemicals which are found inside of the water and they are heterotrophy meaning that they do not use sunlight to manufacture their own food, so they eat their food rather than producing the food". They convert food such as sugar into alcohol to get their energy. There is no nucleus inside the cell of prokaryotic organism. Animal fossils are known as a eukaryotic, which means that their cells do not have nucleus (Kazlev, 2002).

Blue green algae are the plants that are found inside the water or ocean. They use sunlight to manufacture their own food and they also create oxygen. They fill the atmosphere with oxygen. Other organisms need oxygen to carry out their life process of growing, feeding, responding, reproducing and they also produce carbon dioxide and the algae also need carbon dioxide to perform their life processes (Kazlev, 2002).

Living organisms are classified as consumers which are animals, producers which are plants or decomposers which are fungi, depending on how they get food. Animals that feed on plants are known as herbivores such as goats and they are called primary consumers. Carnivores like lion are animals that feed on meat and omnivores are animals that feed on both plants and animals, e.g.: human and baboons (Kazlev, 2002).

Environmental limiting factors such as temperature, water, light, competition and soil contribute on the survival of both plants and animals. So every organism needs certain requirements for their survival. Sunlight and rainfall affect plant growth. These two limiting factors can help the plant to grow well and animals leave the habitat where there are a lot of plants so that they can hide themselves from their energy.

Reference:

1. Kohler, S. Plants, [Internet] 2006 May 8, 14:30. UTC [cited 2006 May 07]. Available from: http://www.blueplanetbiomes.org/plants.htm

2. Kazlev.A.M. 2002, PLANT,(land plants) [Internet] 2006 May o8, 14:00.UTC [Cited 2006 May 07, 10:12]. Available from:
http://www.plalaeos.com/plant/default.htm



Lizzy Maluleke
CSIR PTA
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Cell number 072 351 8488
Tell [012] 841 2133
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SIGNALS USED BY INSECTS TO ATTRACT A MATE FOR SEXUAL REPRODUCTION

Insects have both male and female species that mate and reproduce sexually. Some insects reproduce by lying eggs while in some the egg hatches inside the female. During other seasons of the year the males are not available to mate with the female but species like aphids still reproduced.

Different insects use different strategies to to attract their mating partners. All these srategies mostly work only where they are reguired, meaning that if the signal is from the female butterfly it will be heard only by male butterflies.Semiochemicals are chemicals that causes interaction between organisms of different sexes. All these semiochemicals serve one purpose, to complete the life cycles of insects. "These chemicals are divided into allelochemicals and pheromones depending on the nature of interactions because the interaction can be either interspecific or intraspecific"(1).

"Allelochemicals are those chemicals that are important to individuals of a species that are different from the source species. These chemicals are also subdivided into different groups depending on whether the respond of the receiver is comfortable with the emitter not the receiver or the chemical is favourable with the receiver not the emitter or is favourable to both emitter and the receiver. Both allelochemicals and pheromones it is always useful to refer to chemicals as arrestants, attractants, repellents, deterrents, stimulants or other descriptive terms. These terms can indicate what behaviour is involved in the response such as a feeding stimulant or flight arrestant. Pheromones are released by a certain species with the effect of having the attraction to the same kind of species" (1).

Insects have different ways they use to attract each other like in the case of the moths. "The female moths have scent glands on the abdomen that secrete pheromones. These chemicals are secreted to attract the male moth. The male moth can detect these chemicals at a distance of four to eleven kilometres. Sometimes the males secrete pheromone just to induce the females so that they mate. Insects like butterflies use colour and movement. The males will be attracted by the coloured imitations of females and in the same time they will be chasing the other male away. Male flies also form a compact swarms that attracts the female" (4).

Sound is also used as a way to attract each other sexually. "The male mosquitoes are attracted to the note or sound produced by the wing vibration of the wing. Female grasshoppers, crickets and cicadas are attracted by the sound produced by their males. Crickets use the burrows to resonate the sound, the cicadas use their large empty space in their abdomen and the substrate vibration helps the leafhoppers to communicate"(4). It is very interesting to see how clever insects are. Especially looking at the different ways the male insects use to protect thier sperms. Some protect them by guarding the female everytime. Some have some chemicals which they put on the female so that she does not mate again until she give birth. Other males use the scoop to sweep other sperms away before they mate.

Reference

1. Nordlund, D. A. 1981. Semiochemicals their role in pest control. [Internet] 2006 May 08; 15:05 UTC [Cited 2006 May 08] Available From: http://ipmworld.umn.edu/chapters/flint.htm

2. Wikipedia contributors. Insects [Internet] Wikipedia, The free encyclopedia; 2006 May 08; 10:23 UTC [cited 2006 05 08] Available from: http://www.ivyhall.district96.k12.il.us/4th/KKhp/1insects/buginfo.html

3. Wikipedia contributors. Neuroendocrine [Internet] Wikipedia, The free encyclopedia; 2006 May 08; 11:15 UTC [cited 2006-05-08] Available From:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7186527&dopt=Abstract

4. Wikipedia contributors. Reproduction [Internet] Wikipedia, The free encyclopedia; 2006 May 08; 14:35 UTC [Cited 2006 May 08] Available From: http://bugs.bio.usyd.edu.au/Entomology/InternalAnatomy/reproduction.html

Dianah Nangammbi
CILLA CSIR
P.O BOX 395
PRETORIA
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Tel: +27 12 841 2133
Cell: +27 73 121 3589
Email: dnangammbi@csir.co.za
http://wwwdianah.blogspot.com/

THE DIVERSITY OF FLYING INSECT LIFE THAT HAS EVOLVED

Insects are “invertebrate animals which belong to the group of class insecta” (2). They are the largest and most widely distributed taxon with the phylum anthropoda. There are “about 925 000 known insect species” (1). For example the dragonfly species, praying mantis, grasshopper, butterfly and moth, fly, tree bug, beetle, bees and ant species.

These insects are categorised into flying insects and non-flying insects. The flying insects such as bees, butterflies, grasshopper and dragon flies have developed their own different characteristics. Their characteristics are seen on the arrangement patterns of wings and their flying pattern. The grasshoppers characterised by two pairs of wing i.e. the inner wings which are very-very soft and the hard outer wings. The wings are attached to their abdomen.

The diversity of flying insects is seen with the example of dragon flies characterised by two pairs of wings which flap up and down synchronously. These two pairs of wings is a special characteristic for this insect because it can fly for long distance at a very high speed. The bees which are characterised by fore and hind wings linked together with hooks. Some of the flying insects have wings that can be folded over their back meaning that they can only spread them when in use. The indirect-flight muscle plays an important role in powering the wings for flying.

The flying ability by insects enable them diversify throughout the world. They gained the ability to explore more territory and find new kinds of food giving rise to more species. Insects easily produce large number of off-springs hence they need only small amount of food. This is another thing which able them to be more than other animals.

These flying insects are also ecologically essential. They play a vital role and they are beneficial to the environment and to humans. Ecologically “they facilitate the pollination process for plants that need to reproduce” (2) for example bees; butterflies receive rewards of nectar and pollen. They play a role in seed dispersal from one point to another. The evolution of different flying insects is very crucial because they produce useful substances such honey, wax and silk. Many insects have been cultured by humans for many years. For example, Locusts serve as food for human.
Insects serve as food for other animals that are feed on insects thus insects are important in the food chain cycle.

Although the flying insects are diversified, they are facing threats. Through pesticides large numbers of insects are killed, although most tend to have some forms of resistance. These flying insects like locust are diversified in such a way that it is possible for them to invade a large portion of land.

Flying insects are very important to other plants and animals. In plants, this is seen during the process of pollination. Some plants cannot reproduce without the aid of the insects. Insects serve as food for other animals for survival.



References

1. A pair of wings took evolving insects on a non-stop flight to domination; [internet] [cited 2006 may 8]. Available from:
http://www.universityscience.ie/pages/scimat_evolving_insects.php
2. Wikipedia contributors. Insects [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 17, 05:19 [cited 2006 May 8]. Available from:http://en.wikipedia.org/wiki/Insects

Mr Lufuno Mukwevho
CSIR Pretoria
P.O. Box 395
Pretoria,
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Tel: (012) 841 2133
Fax: 012 842 7024.
Cell: 0723175626
E-mail: lmukwevho@csir.co.za
My blog URL: http://mukwevholufuno.blogspot.com

HOW THE FIRST PLANTS AND ANIMALS EVOLVED AND BECAME DEPENDANT ON EACH OTHER.

During the period of Cenozoic era, "co-evolution between plants and animals species occur"(4). It has been profound that certain plants and insects influence another in evolution, in a process known as mutualism where all organisms benefit from each other. They firstly evolve in the aquatic environment before they evolve on land.

Species that co- evolve were single cell plant and multicelled eukaryote organism, "the blue-green algae was the single cell plant which evolve on the sea"(2). It was the first species to generate its own food in a process known as photosynthesis where sunlight and water are used; during this process oxygen is also generated. While animal cannot produce its own food," they depend direct or indirectly on plants for its survival, and for animal to be evolved on earth it is traced back to plant this show dependency of animal to plant". (2)

"The oxygen that the algae produce spread all over the aquatic environment, it began to fill the atmosphere and this made it possible for other organism to develop".(2) Because of high concentration of oxygen produced by algae in the atmosphere, it tends to give access to animal species to evolve on land. Oxygen form part of ozone layer in the upper atmosphere which tends to block the dangerous ultraviolet rays of the sun, these rays was making it impossible for organism to live out of water. But it was simple for plant to survive on land because they can utilise the ultra violet rays into food.

Simplicity of plant to convert sunlight into food made it possible for plant to evolve on land, and the first plant to evolve on land was Mosses. This made it possible for other animal to evolve on land, because of the oxygen generated by plant which forms the ozone layer that block the ultraviolet which restrict life of organisms to exist on land.

Mutualisation which has develop between plant and animal species during co evolution influenced by the resource that they need to survive on, during pollination plant depend on animal or insect.while insect or animals depend on plant for oxygen and plant depend on carbon dioxide which is released by organism as by product which is used to generate food in the process of photosynthesis. For each species to survive it have to depend on the other directly or indirectly. (4)

This dependency between plant and animal species can be seen during reproduction, where plant depends on organism to transfer pollen grains to the female flowers. This helps the plant to reproduce and increase plant population, which is simple method to transfer pollen than wind pollination which need quality seed to be dispersed. While organisms benefit from plant through food and habitant for reproduction that the plant provides, mostly this happens to insects such as moth and bees. (4)

Sometimes plant and organisms become total depend on each other, this happen when one insect only function to pollinate their pollen grains only and it find habitant on the same type of plant ‘s flower. Some become specific to that species only and they protect that species from herbivores. For example, species such as "Yucca (Plant) and Moth(organism) they depend on each other yucca provide habitant for moth and allows it to reproduce on its flower where its larvae (caterpillar) live in developing ovary and eat yucca seeds,(4) while moth function as the pollinator". (3)

"This mutualism can also be seen in the acacia trees and acacia ants, these ants are specifically depends on the acacia tree for foods. They tend to protect the acacia tree from the herbivores which feed on it and also prune the seeds of any plants that found under acacia tree. This ants sting the animal that feed on acacia or scratch on it, and the ants benefit from the substance that the acacia produce as a food". (4)

In conclusion, plants and organisms depend on each other in a process known as mutualism where all benefit. plant play a role in bring life on earth as the primary producer of factors that sustain life, while animals generate carbon dioxide that sustain plants and also increase the population of plants in the process of reproduction, organisms function as the pollinator.
All in all most of the species in the environment depend directly or indirectly to the other.

References:

1. Kazlev.A.M. 2002, Plants, (Land plants) [Internet] 2003 April 28 [cited 2006 May 08].Available from: http://www.palaeos.com/Plants/default.htm

2. Kohler, S. Plants, [Internet] 2006 May 8, 14:30. UTC [cited 2006 May 07]. Available from: http://www.blueplanetbiomes.org/plants.htm

3. Mrs.Ramsay.M. (et al).1995[internet]the Yucca Plant and the Yucca Moth.[cited 2006-May-08]Available from:http://www.emporia.edu/ksn/v41n2-june1995/introduction.htm

4.Mr.Carter J.S.1999.Coevolution and Pollination.[Internet]cited 2006-May-08]Available from:http://biology.clc.uc.edu/courses/bio303/coevolution.htm



Mr Elelwani Muanalo
NISL- Ecological Informatics Student
CSIR Pretoria
Tel: +27 12 841 2133
Fax: +27 12 842 7024.
Email: http://www.blogger.com/emuanalo@csir.co.za
My bloger URL: http://www.emuanalo.blogspot.com/

THE DIVERSITY OF FLYING INSECT LIFE THAT HAS EVOLVED

Insects are small animals around us. They are regarded as invertebrate animals. They are grouped in the class Insecta. The insects are the largest and “most widely distributed taxon in the phylum Arthropoda” (3). They seem to be consisting of six legs and the three body parts. Their body parts are namely; the head, thorax and abdomen. Some of the insects are having one pair of wings, others are having two while some are having three pairs of wings (3).


Ancient types of insects were seen since the early dinosaur days. It seems as if these types of insects evolved for flying long time ago before some of the birds could fly. The class insecta is divided in to two subclasses, which are further divided into orders. The sub class Apterygota is divided into two orders, the microcoryphia known as “dragonflies, damselflies and the zygentoma known as silverfish, fibre brats” (3). These insects were known to be jumping insects, because they did not have wings. It seems as if they were indoors types of insects, spending much of their time under the sinks, bookshelves, etc (2).


The dragonflies and the damselflies are the insects of the subclass Apterygota. These insects evolved into the subclass zygentoma. According to the Insecta the insects in the sub class Apterygota are wingless. The lack of wings of these insects resulted as their disadvantage of being diverse. “After the insects gained the ability to explore more territory, they found new type of food which increased more species” (2). This resulted when they evolved the ability to fly. For example: the insects from the microcoryphia order evolved into the Odonato order (2).


The Odonato insects had about two pairs of wings. They were regarded as the best fliers. These insects were eating other insects caught on fight (1). The early flying insects seem to have expanded wings that stuck straight. It really shows that insects did not only develop for flight, in the past 300 million years ago, some of the insects had evolved folding wings. This modernism really gave the diversity of insect’s improvement. Those insects can keep their wings safely tucked away as “they move slowly through leaf litter, squeezed under tree bark or even dived into water” (3).


The evolution of insects became successful because of the plants. The insects depend on the plants for their survival. It seems as if plants play important role to insects, for example, by providing large amount of food for the insects. The insects evolved “defences against the sophisticated chemical weapons in plants”. There are some of the insects that are able to recycle the poisons from the plants, for example monarch butterflies (1).


Evolution happens every where, even in insects evolution took place. Some of the insects descended from other insects, for example fleas descend from mosquito. Fleas are just like the scorpion flies, “they have long wings and powerful eyes, aiding them in finding insect carcasses for food” (3). The boreids are known to be the flea’s closet relatives alive. The boreids seems to have the knowledge on how the scorpion flies evolved. “These 24 species walk across snow in late winter to feed on moss. Unlike other scorpion flies, snow fleas have tiny wings that are useless for flying. They don't have the keen eyesight of other scorpion flies, probably because they need their eyes only to detect predators” (3).



References:


[1]. [http://www.universityscience.ie/pages/scimat_evolving_insects.php, accessed on 07/05/2006: 09:00].


[2]. The family tree, [http://www.insecta.com/insecta/tree.htm, accessed on 06/05/2006, 12:00].

[3]. Wikipedia contributors. Insect [Internet]. Wikipedia, The Free Encyclopedia; 2006 May 06, 12:59 UTC [cited 2006 May 23]. Available from: http://en.wikipedia.org/wiki/insects.



Ms Evelyn Maleka
CILLA CSIR
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Tel: (012) 841 2133
Fax: 012 842 7024.
Email: emaleka@csir.co.za
http://malekaevelyn.blogspot.com/

THE SIGNAL USED BY INSECTS TO ATTRACT FOR SEXUAL REPRODUCTION


The sexual reproduction of insects occurs in different ways. They are male and females insects that mate and reproduce sexually. Sometimes there is shortage of males then some female’s species may reproduce. In a few species females produce only females. Most female’s insects have one or more spermatozoa where sperm can be stored and can be support by secretions from the spermsthecal glands. Female’s reproductive organ consists of ovaries, bilateral Oviducts, a common Oviduct and a vaginal.
The male reproductive systems consists of paired testes, where the sperm produced, seminal vesicles and is where sperm are stored,, accessory glands and a common ejaculatory duct. Mating is important for sexual reproduction. After mating, female’s insects from many species become less attractive.

Different insects used different sign to attract others. Some of these insects release glands called pheromones. However male hide a pheromone to make the female to mate. Intraspecific interaction species release Allelochemical. All these chemicals are called semi chemicals which are used for attraction.
Some insects used sound to mate but others used visions to mate. However females’ scorpion flies require a marriage gift of food from the male before mating. Then the males’ mates with her while she eats, because of these male are selected by the size and quality of gift. Further more those females can enjoy to mate with male. This is done by scorpion flies insects.

Insects used displays or dancing as a sign to attract females to mate. This is some of the strategies that are used by insects. Male fight or decide the winner by comparing size. Remember that the scorpion flies insects did not use this strategies. Some female insects not mate unless the male is in possession of a suitable territory or food source, These is done by other insects. Although female moths have smell glands on the abdomen . These chemicals attract males.


Vision is another strategy that is used by insects such as Butterflies. Butterflies are one of the important types of insects. One can said that, butterflies used colour and movement to attract male to mate. Because of these colours that are used by butterflies, then the males will follow coloured imitation by females.
Some male’s flies form dense group, when the females see that group, then they are attracted by the sight of these groups and they start to enter and select mate. Male fireflies as an examples are attracted “by, and fly to, the light beat produce by the wingless females” (2). I is said that both sexes of butterflies are meet on hill tops or other geographical outcropping and is where they will select a mate, but other insects form a group as I indicated above.

Mating strategies through sound. These are some of the strategies that are used mostly by mosquitoes one can know that mosquitoes are one of the important types of insects, and the male mosquitoes are attracted by the message produced by the wing vibration of the female. But some grasshoppers and cicadas are attracted by the sound produced by their males. Crickets use their burrows to resonate the sound, but cicadas use the enlarge empty space in their abdomens. Some leafhoppers communicate by using substrate vibration.
Males are allow to leave females after mating, giving those males opportunity to increase their reproductive success by locating and inseminating additional females. In many insects’ species, seminal fluid received from fluids during mating mediate post mating behavioural and physiological changes in females. http://www.ivyhall.district96.k12.il.us/4th/KKhp/1insects/buginfo.html

Just conclude, insects use sight, smell, sound, pheromones, nibbling and waving of abdomen as a strategies or sign to attract mate for sexual reproduction. When we talk about sound, we are referring to the noises that are made by insects. Species that do not use courtship, they use pheromones and Allelochemical as a strategies to attract males for mating.


References

1. Hoffmann, M.P. and Frodsham, A.C. 1993 Insect Facts and Information. [Online]. Available from:
http://www.ivyhall.district96.k12.il.us/4th/KKhp/1insects/buginfo.html[2006, May 08 13:11]

2. Knight,R. bcb Biodiversity Chapter 2. The swaming Horders [Cited 2006, May 08]. Available from:http://planet.uwc.ac.za/nisl/biodiversity/Chapter2/page_40.htm

3. Nordlund, D,A, 1981. Semiochemicals their role in pest control. [Internet] [Cited 2006 May, 08]. Available from:http://ipmworld.umn.edu/chapters/flint.htm

Linette Netshiheni
CSIR
Pretoria
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