Spiders are not insects but invertebrate predators arthropod class Arachnida as scorpions, pseudo- scorpions and mites. There are approximately 40,000 species of spiders in the world, with nearly 700 in Quebec.
These arthropods do not undergo metamorphosis. That is to say that young people , also called juvenile resembles adults smaller. Growing up, spiders change when the exoskeleton becomes too small.
Spiders have a very important ecological role because they are voracious predators and consume large quantities of insects . In feeding , they regulate populations and provide a form of biological control in many natural environments. Certain agricultural use them to control pests in the fields.
The main predators of spiders found in nature are :
- Wasps are predatory spiders, they paralyze the sting in the stomach takes them to the nest to feed their larvae.
- Many reptiles and some amphibians.
- The so-called insectivorous birds ( thrush, wagtails , robin , wren, etc.).
- Some mammals such as bats, hedgehogs , foxes .
Spiders are found everywhere in nature. However, several species live indoors or on buildings, they weave their habitat with the silk is also used to put their eggs.
It is imperative to realize that 80% of suspected symptoms attributed to spider bites in Quebec are not . Other invertebrates are responsible as bedbugs , fleas or ticks .
Most spiders do not bite humans , and if it happens, it causes a slight skin reaction like a little minor swelling, inflammation or itching . Except in the case of venomous spiders that can cause serious local and systemic reactions can sometimes be fatal.
The Canadian Food Inspection Agency (CFIA) has found that grapes imported from the United States contain more frequently than before the mid- venomous spiders fruits , especially because U.S. producers replace pesticides by insects.
FEW POISONOUS SPIDERS IN NORTH AMERICA ARE :
- black widow found in the United States and southern Canada
These spiders are not very large , the size of the body is about 1 cm and about 5 cm their paws. She bites especially in summer and early autumn when provoked . These spiders spin their webs in plants , rocks or in garages and roofs .
The venom of the black widow affects the nervous system . The bite of this spider to feel a pinprick . Some people feel nothing at all. However, others may have severe pain and cramps that spread from the site of the bite to the large muscles of the arms , legs and abdomen . This usually occurs within 30 to 60 minutes after the bite . In addition to these reactions , other symptoms are observed as salivation, increased blood pressure, blood vessel constriction , fast heart rate , headache , nausea, vomiting. The venom can even be fatal for children or the elderly
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- brown recluse spiders (found in the southern United States);
This spider is brown and has a small dark shape violin shape on the back. Its body measures 1.5 cm , legs can reach 4 cm. They hide under rocks and logs and emerge at night to hunt. They often enter homes and hide in dark, quiet places . The bite of a brown recluse spider is painless, but it causes painful itching after a few hours , and affects the skin and surrounding tissues , forming a bluish around the bite white circle and sometimes swelling accompanied by the occasional destruction of cells skin . After 2 to 3 days, the toxin can cause in some people , fever , vomiting and headache .
- Tarantulas or spiders ( they are found in the southern United States)
Tarantulas are large, hairy spiders with a leg span can reach 25 cm. Once they feel threatened , tarantulas eject thousands of small hairs on his hind legs that are capable of penetrating human skin and which contain a toxin causing a severe rash . " .
Engineering extermination favors the use of environmentally friendly methods and biological products with low impact
