Red Back Spider - Bites & Control
Red Back Spiders and Spider Control Sydney
All Guard Pest Control
Specialising in termite control in Sydney, Australia. We also control all spiders, cockroaches, and termite inspections
We specialise in treatment of the Red Back Spider, and the treatment of their painful bites
Address: P.O. Box 281 Windsor 2756
Phone: 1800 333 337 Mobile: 0408 655 795 Facsimile: 02 45743099
Email: info@allguardpestcontrol.com.au
Free Call 1800 333 337
Manager: Rudy Tschaut
All Guard Pest Control services the Sydney Metro area. The services provided range from general pest treatments, termite management programs including termite inspection and pre-purchase inspections.
Red Back Spider Control
Red Back spiders and their control. All Guard Pest Control services the Sydney Metro area, the services provided range from general pest treatments in domestic and commercial premises, red back spiders, termite management programs including termite inspection and pre-purchase inspections.
Spider Control Information
(Latrodectus hasselti) Family Theridiidae
Redback spiders are prolific throughout Australia but are less common in colder
regions such as Melbourne. In Sydney, they are very common in populated areas, usually hiding in
rubbish, leaf litter and under pot plants. Hundreds of bites are reported each
year but less than 30 percent require antivenom treatment. Before the antivenom
was available, Red back spider bites caused about a dozen known deaths until Dr Straun
Sutherland discovered the cure.
In a 13 year period (1963-1976) over 2000 cases of Red Back Spider bite were
reported to the Commonwealth Serum Laboratories (Sutherland and Trinca 1978);
many more bites are reported to doctors, hospitals, and poison information
centres throughout Australia. Because the bite can be potentially dangerous it
is wise to be informed about the Redback Spider, its habits and behaviour.
Prior to the introduction of the specific antivenom in 1956, 13 deaths in
Australia were caused by its bite.
Only female Redbacks usually bite people - the males are too small. Redback
spiders are typically entirely black, except for a broad red band down the back
of the body and a red hourglass-shaped mark underneath. Large females may span a
50 cent coin, but males are much smaller. Immature spiders do not have the
typical colouring. They are not native to the area, but are common in Sydney and
are sometimes seen around houses on the range.
Redbacks build anywhere out of the direct effects of the weather - on buildings,
in parks, under steps, in corners, grass, junk piles,, under window sills,
around pot plants. They are generally timid except when an object is placed in
the web, or when tending young or eggs in the nest. Only the female is large
enough to effectively bite people. They are highly venomous.
Redback Spiders belong to the genus Latrodectus or widow spiders. Australia has
another widow spider, the Brown Widow Spider (L. geometricus), a circum-tropical
species that is found in northern Australia. Its bites are not frequent or
severe. There are many widow spider species worldwide including the infamous
Black Widow Spider, L. mactans, of America.
No deaths have occurred since its introduction almost 50 years ago, although a
small child was bitten in Melbourne a few years ago although was not fatally
injured, she was on the critical list for a few days.
First aid for bites
Pressure bandaging is not recommended for Redback bite as this can aggravate the
pain. Because the venom molecules are large, they can take some hours to be
transported from the bitten area via the lymphatic system and into the blood
stream. Medical attention should be sought if a bite is suspected. Cold packs or
cold water may help relieve pain.
They also known as jockey spiders, are members of the widely
distributed Latrodectus genus. Other members include the black
widow (L. mactans) and brown widow (L. indistinctus) of North America, the
thirteen-spotted spider (L. tredecimguttatus) of Europe and the katipo (L.
katipo) of New Zealand. Redback spiders are distributed throughout Australia,
and have adapted well to an urban environment. They are common in sheds and
garages, under houses, in industrial areas and in outside toilets. The venom
acts directly on the nerves, resulting in release and subsequent depletion of
neurotransmitters.
Bites by this spider represent the commonest envenomation requiring treatment in
Australia, particularly over the summer months. More than 250 cases receive
antivenom each year. Perhaps ten times as many cases are mild or unrecognized
and do not receive antivenom. Males appear to be more frequently affected than
females, probably in relation to occupational exposure. The spider is usually
easily identified by the presence of a red, orange or brownish stripe on its
abdomen. Only the female is considered dangerous, and it is generally a retiring
spider, biting only defensively. Bites are typically sustained when the spider
is disturbed in the garden or shed, in clothing (especially footwear) or even
when it is sat upon. Bites to the limbs comprise approximately 75% of cases. The
male is very small, only about 3 mm in diameter, and his fangs are unable to
penetrate the skin.
Symptoms and Signs of Bites
The time course and the actual symptoms are highly variable, but progression of
the illness is generally slow, and symptoms may persist for weeks after an
untreated bite. The acute symptoms include:
- Immediate pain at the bite site +/- erythema and swelling .
- Pain progressing to involve the entire limb
- Painful or tender regional lymph nodes.
- Sweating, sometimes affecting only the bitten limb initially, and sometimes over bizarre distributions distal to the bite site
- Nausea, vomiting, abdominal pain
- Headache
- Migratory arthralgia
- Fever
- Restlessness and insomnia
- Hypertension
Treatment of Bites
Sutherland (1983) recommends that no special first aid be applied because as the
venom is slow acting and localising it may intensify the pain at the bite site.
Pest control firms now receive training in the treatment of the bites
as part of their modules for pest management. The best action is to transport the person immediately and without panic to
medical aid. Serious illness apparently does not develop for at least three
hours, so this is plenty of time in most cases to get the victim to hospital
where first aid may be administered. In 2144 cases surveyed from 1963-1976
(Sutherland and Trinca 1978), antivenom was administered in most cases.
The exact mechanism(s) by which the toxins produce the observed clinical effects
are poorly understood, as is the precise cause of death. No deaths have been
reported since 1955, a year before the introduction of redback spider antivenom
in Australia. Unusually, antivenom may be effective even if administered several
weeks after the bite.
The Red Back Spider is one of Australia's best known spiders; it
earned much of its reputation through `a large proportion of the recorded bites
having been sustained in outdoor privies' (Taylor and Murray 1946). That
activity, wrongly attributed to the male, was immortalised in Slim Newton's 1972
hit song, "The Redback on the toilet seat":
There was a Redback on the toilet seat when I was there last night.
I didn't see him in the dark but, boy, I felt his bite"
They occur throughout Australia but are most common where the natural
environment has been disturbed, such as settled or urban areas. Within natural
forest, they are rare to absent. These facts plus the spiders' ready
ability to invade and colonise newly settled suburbs imply that Redback Spiders
may not be native to Australia. They were first recorded in 1870, but by that
time about 200 other spider species had already been found. If Red-backs
were as common then as they are today, they should have been recorded sooner.
Very similar species of Latrodectus occur in the Pacific Islands, New Zealand,
Europe, and North and South America. Further, it was at the seaports of
Rockhampton and Bowen that the Redbacks were first collected and this adds
strength to the supposition that that a foreign spider may have been carried
here unwittingly by ship.
The initial bite is often felt but is apparently painless, although some victims
have reported burning sensations (Taylor and Murray 1946). Puncture marks are
not always evident. In the majority of bites intense local pain is experienced
about five minutes after the bite (Sutherland 1983). According to Weiner (1961),
in about 40 percent of bites the symptoms included sweating and/or some
neuromuscular activity such as muscular weakness, paralysis, stiffness, loss of
coordination, tremors, and paresthesiae; and in about 10 percent, muscular
weakness, nausea, vomiting, local swelling, dizziness or fainting, local
redness, tachycardia, palpitations, insomnia, rigors, fever, and muscle spasms
were also recorded. Some reactions can be quite unusual (Sutherland 1983):
tetanic spasms, tingling in the teeth, swelling of the tongue, infection of the
bite site, convulsions, thirst, diarrhoea, shock, rashes, patches of sweating,
periorbital oedema, and others. However, the diagnostic indication of a Redback
Spider bite is localised sweating at the site of the bite.
Webs
The web of the Redback Spider is an irregular tangle of fine but strong silk.
The back portion of the web forms a funnel (visible from certain angles) where
strands of silk are more closely bound. It is here that the spider and egg sacs
are found. Many spiders that are similar in shape and colour to Redback Spiders
build similar tangled webs; however, those webs are generally weaker and usually
the spider rests centrally in the open web.
Location of habitat
They seem to prefer locations in which the outer portion of the web has some
exposure to sunlight, and the inner portion of the web is usually tucked away in
a cool dark recess. Occasionally, webs may be found on exposed walls with only a
narrow ledge as shelter. Along the outside of the house, they may be
found under window sills, under the guttering and eaves, in the corners of
windows and doors, amongst pot plants, under and on steps and verandas, and, of
course, under the seats of outdoor toilets. Melbourne pest control treatment for
these areas include direct removal of spiders and webbing. Inside houses, the possible
locations for webs are even more numerous but because the spiders tend to stay
near the sun they occur infrequently inside.
Away from houses, Redback Spiders seem more numerous because there are more
hiding places; piles of wood, iron, cans, and old machinery are ideal hiding
places. Such is the tenacity of the spiders that they build in grass tussocks
and the little shelters provided by sods of freshly ploughed fields. Frequently,
they are found on and within motor vehicles in use; locations
reported are in the handlebars of motorbikes, and on seatbelts and behind the
bumper bars of cars.
Life Cycle
A Redback spider may lay eggs every 25-30 days. In one group of about 9-12 egg
sacs (up to 29 have been recorded) a single female may lay up to 5000 eggs. The
eggs hatch 13-15 days after being laid (often near the onset of rain). Females
may mature in 60 to 325 days but average about 4 months. The smaller male
matures in 37-167 days; on average in about 90 days. Females live for between
two and three years; males live for up to 6 to 7 months. Without food, spiders
survived about 100 days on average; the first to die lived only 36 days but the
last lived 7 months.
Often, houses that are covered with the Black House Spider are free or almost
free of Redback Spiders.
Pest Control
This spider has established itself successfully in Australia. It is a
hardy spider than can stand high temperatures and prolonged dry periods; it is
completely indiscriminate about where it builds its web; and it constructs a
deep recluse to maintain its security. How, then, can the spider be controlled?
Spraying with insecticides is one possibility. However, like all spiders, they can close off its lung openings and exist for several hours using
very little air. Hence, a spray must be very long lasting, or used in such
volumes that the spider and all of its surroundings are drenched. Surface-acting
sprays seem to work reasonably well. However, even if a `total kill' is
achieved, the spraying must be repeated frequently, because one decent breeze
can carry in a new batch of young spiders that can quickly recolonise a `clear'
area. Sprays are typically delivered from positions higher than the nest and may
not actually affect the spider high up in the nest. Equally, the silk of the egg
sac is impervious to such lightly delivered sprays and the young continue to
develop within the sac. Hence, spraying must be repeated about 4 weeks, covering
all of the same areas.
The curiosity of children is often aroused when they see webs and spiders, so if
young children are in the area, it is important to pay careful attention to low
ledges which are best seen by getting down close to the ground and looking up.
Once an area has been thoroughly checked and the spiders and egg sacs destroyed,
a weekly casual check and eradication will substantially reduce the numbers of
young Redback Spiders establishing themselves.
Redback spiders are most vulnerable in the cool dry winter. Insect food is
scarce and the spider is forced to live on available reserves. Watch the sun.
Look for areas that are heated throughout the winter's day or a good part of it.
Those are most likely spots because Redbacks need to stay warm and dry. A
sustained attack on Redbacks during the winter will ensure a much quieter spring
and summer to follow.
Redbacks survive the winter only in areas which have sufficient sun on the web
or on the retreat to warm the spider up to about 15-20øC for about an hour or
so. Early onset of summer heat and dry conditions will allow early mating and
extra generations.
Redbacks are often absent in gardens that are well kept, moist, with much shade,
even in Sydney’s summer and are most common around houses that have few shrubs
or trees that provide shade.
Choose All Guard spider treatment! If spiders are a problem, call or email us at info@allguardpestcontrol.com.au for information on Red-Back spiders & pest control.
Phone: 1800 333 337 | Fax: 02 45743099
Email:
info@allguardpestcontrol.com.au
