Why do mosquitoes bite? - Male mosquitoes are harmless vegetarians which feed solely on plant nectar. They do not bite. Females, on the other hand, need blood meals to provide the vital protein that enables them to produce eggs: no blood-no reproduction.
Chemical substances that attract mosquitoes include variuos amino acids, ammonia, lactic acid, butyric acid and other substances excreted by human skin.
In order to find their host and "blood donor" mosquitos are equipped with a complex sensory system allowing them visual orientation and piloting by other stimulants. The most important are: heat, humidity, carbon dioxide and chemical attractants.
In simple terms, mosquitoes are attracted by the odor of their host and can locate him or her by following concentration gradients in the air. They always fly in the direction in which they perceive the host's odor to be the strongest. As soon as the insect finds an attractive area of skin, it starts feeding. It pierces the skin with its proboscis - a combined saliva and feeding tube equipped with small teeth. The host generally fails to notice the bite because the proboscis does not normally come into contact with any nerve endings. The mosquito then injects a secretion into the wound that widens the blood vessels to increase the blood flow. At the same time, this secretion prevents the host's blood from coagulating and blocking the proboscis. The host will now notice the bite, but it is better to allow the mosquito to finish extracting blood to ensure that none of the proboscis is left in the skin.
Once the insect has sucked enough blood, it leaves the host. It does not attack another victim but lays its eggs, and another reproductive cycle begins.
Avoiding mosquito bites is a reliable way of preventing diseases such as malaria, dengue fever, west-nile virus and yellow fever.
True flies (Muscidae): The Muscidae are a large family of flies typified by three individuals; the house fly, Musca domestica, which breeds in decaying substances and excrement; the little house fly, Fannia canicularis, most commonly found inside buildings; and the stable fly, Stomoxys calcitrans. There is one major difference between the first two and the stable fly: they do not bite, and represent more of a hygiene problem and a nuisance. Stable flies do not require animals to breed; they also bite humans. They only land on their host to suck blood, and they cover great distances in the search for hosts and breeding places.
In contrast to other flies, the mouth part of the male and female flies in this family are largely identical and both genders bite. Their mouth parts are also constructed using a completely different principle. They push their entire proboscis into the skin like a needle. Small barbs on the end of the proboscis are moved from side to side to gouge a hole so that the proboscis can be pulled further into the host's skin, and this procedure is very painful for the host.
The larvae of horseflies develop in animal excrement or decaying plant matter such as grass cuttings, waste from packaging plants and aquatic vegetation washed up on shore. Stable flies develop rapidly, and several generations can be produced during a single summer. In contrast to the members of the families mentioned above, the pupae of stable flies hibernate. Stable flies can transmit bacteria with their mouth parts, causing diseases such as tularaemia (rabbit fever) and anthrax. Like the horseflies (Tabanidae), stable flies are very cautious blood-suckers and can bite several animals many times before they are replete.
Black Flies (Simuliidae): There are no biting flies which are feared as much as black flies and anyone who walks through a Canadian forest in June and July will find out how justified this fear is. Black flies of the species complex Simulium venustum may be so numerous, and their attacks may be so unrelenting, that it is practically impossible to go outside during the daytime without protection.
Black flies often land repeatedly and fly away again without biting. Their frequency and their readiness to bite both increase as sunset approaches. But even when they are not biting, their constant buzzing and crawling over the skin is as much of a nuisance as their bites. Victims have to wait until darkness falls to find relief from these flies; unlike mosquitoes and midges (Culicoides species) black flies do not attack at night.
Black flies can't bite through clothing, but they commonly crawl into people's hair or under their clothes and bite accessible places such as the ankles and waistline. Black flies are heavily influenced by colour: they find dark shades more attractive than light ones, and blue, purple, brown and black more attractive than white or yellow. For this reason, a light-coloured shirt is a far more sensible choice than a dark-blue one.
Black flies are more selective in their choice of host than mosquitoes, and relatively few species suck human blood. Most general appear to feed only on bird blood, and many of them evidently do not suck blood at all since their mouth parts are underdeveloped and apparently unsuitable for feeding in this way. However, black flies that bite birds may also be attracted to humans, and in large numbers they can be a real nuisance even if they don't bite.
In North America and Europe the tick season lasts from May to November. The risk of infection is especially high in May, June and September and in years with dry, hot weather. The risk is lowest in July and August.
Like mosquitoes, ticks transmit diseases when they suck the blood that they need for their development. But in contrast to mosquitoes, ticks generally require several blood meals. A tick often takes several weeks to find a host, waiting on stalks of grass or ferns, in bushes or on the underside of leaves until the right one comes along.
Sandflies (Phlebotomen): Leishmaniosis is a disease caused by parasites which is transmitted to humans and animals by sand flies.
The female sand fly stings a host or an alternate host, sucks its blood and then transmits the disease by stinging a human or animal.
The sand fly was almost exterminated during the fifties but has since made a comeback. The number of humans and animals infected with Leishmaniosis is therefore rising steadily.
More than 12 million people worldwide are currently infected with Leishmaniosis. While it occurs mainly in tropical and subtropical areas, Mediterranean countries such as Southern France and Spain are also affected. Cases of Leishmaniosis have also been found in Germany; sand flies were found in the South of Germany in 1999.
Some 350 million people worldwide risk being infected with Leishmaniosis. The number of people infected increases by more than 1.5 million every year.
Horseflies (Tabanidae): Horseflies are blood sucking insects and belong to a fly sub-species. They prefer bushy, woody surroundings which are humid or swampy. In most cases, the female horsefly feeds upon blood while the male horsefly feeds upon nectar. The sting of a horsefly is more painful when compared to that of a mosquito because the mouth of a horsefly is significantly larger than that of a normal mosquito. During the blood sucking process, the female horsefly injects an anticoagulant secretion into the bite wound. Because the wound is relatively large, secondary hemorrhaging usually occurs upon completion of the injection process. Horseflies are able to inject up to 0.02 ml of blood.
Diseases such as anthrax, leptospirosis, loa loa and tularemia are known to be transferable to humans by horseflies. The horsefly is also suspected of transmitting sleeping sickness to humans.
Horseflies are not, however, only irritating to humans. Horseflies are also troublesome for horses. Therfore products based on Saltidin® are developed to protect horses from this pest.
It is therefore very important to Saltidin® to protect oneself against all mentioned inscects.
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