Spiders

Question 1

What are the symptoms of neurotoxic venom?

Answer 1

Immediate pain from the bite site. Followed by usual neurotoxic symptoms - Dizziness; shortness of breath; muscle cramps (abdominal muscles become rigid); skin flushed; sweaty and swelling of lips and face; sometimes causing feelings of anxiety and panic or terror; if death occurs it follows weakness; coma and breathing difficulty (no conclusive reports from S. Africa)

Question 2

Do all spiders in Southern Africa have venom?

Answer 2

All except the Lace Orb-web Spiders (Family Uloboridae)

Question 3

Which 2 species of Baboon spiders are most commonly encountered?

Answer 3

1. Horned Baboon Spider - Ceratogyrus - Prominent “horn” on centre of carapace - Burrow entrance flush with surrounding substrate 2. Golden-brown Baboon Spider – Pterinochilus (The family has changed to Augocephalus sp.) = Burrow entrance slightly raised above substrate with woven matter

Question 4

Which sex of Baboon spiders dig a burrow and how many can they dig in their lifetime?

Answer 4

Females and they can only dig one as they lose the “rastellum” on their chelicerae during their final moult so are unable to dig a new burrow.

Question 5

What are the symptoms of cytotoxic venom?

Answer 5

Little or no pain at bite site. Followed by usual cytotoxic symptoms - Itchy red raised area at the site of the bite (paired puncture marks may be visible); after some hours a painful blister with pussy fluid develops; this peels off leaving an ulcer; may take about 2 weeks to heal (depending on the degree of tissue damage); varying degrees of necrosis may result; depending upon the species responsible

Question 6

How do jumping spiders jump?

Answer 6

Jumping spiders are known to be able to jump by pumping haemolymph into their jumping legs - Hydraulic action of haemolymph

Question 7

What are the characteristics of the Araneomorph sub-order of spiders?

Answer 7

1. “Web bound”- not all build webs (“Jumping spiders”) 2. Diaxial Chelicerae 3. One pair of booklungs 4. Usually fairly short-lived (a year or less

Question 8

How many different types of silk do spiders produce?

Answer 8

Spiders can make as many as seven different types of silk; although most spiders are capable of making four or five different kinds. Making their intricate webs is the most well-known use of spider silk; but it’s far from the only one. Some spiders build nests and cocoons from their silk; and some use silk strands to wrap up their prey.

Question 9

What small kleptoparasitic spiders are often found on the webs of Golden Orb-Web spiders?

Answer 9

Dew-drop spiders

Question 10

What are the differences between Solifuges and Spiders?

Answer 10

Solifuges

1. “Sunspiders” / “Red Romans”
2. No silk glands
3. No venom glands
4. Appear to have 10 legs (“first pair” are sensory pedipalps)

Spiders

1. All have silk glands
2. All have venom (except a single genus Uloboridae – Lace orb-web spiders)

Question 11

Name 4 different types of spider webs

Answer 11

1. Orb-Webs
2. Sheet-Webs
3. Tunnel-Webs
4. Scaffold-Webs

Question 12

What type of venom does the Violin Spider have?

Answer 12

Cytotoxic

Question 13

What are the 2 sub-orders of spiders?

Answer 13

Mygalomoprhs and areaneomorphs

Question 14

What type of venom does the Black Button Spider have?

Answer 14

Neurotoxic

Question 15

How do spiders move around web without sticking to it?

Answer 15

In order that they are able to do this the following would need to apply:

• Many “hang” on their webs
• Feet (“tarsi”) have claws and stiff bristles which are kept extremely clean. Web is held between these structures, enabling the spider to move freely
• Some may make use of “access” strands that are non-viscid and enable free and easy manoeuvrability around the web.

Question 16

What is a stabilimentum and what spiders create these?

Answer 16

It is the “zig-zag” structure built into the webs of certain species of spider.

The reason for these is believed to be that of making the web visible to larger animals/birds so that they avoid it; helping to reduce irreparable damage to the web that would be caused if a large animal unintentionally breaks through it.

It has also been suggested that they assist in strengthening/tensioning the web; or luring insects via ultraviolet reflection. It is also suggested that it is used as camouflage to hide behind in their web e.g. Garden Orb Web Spider

Question 17

What type of venom does the Brown Button Spider have?

Answer 17

Neurotoxic

Question 18

Are Sac spiders diurnal or nocturnal?

Answer 18

Nocturnal

Question 19

What type of venom does the Six-eyed Crab Spider have?

Answer 19

Cytotoxic

Question 20

What features would you look for to identify a Sac spider?

Answer 20

Cheiracanthium have a black “face” & chelicerae and the first pair of legs is noticeably longer than the fourth pair

Question 21

What two types of venom are found in spiders?

Answer 21

Neurotoxic and cytotoxic venom

Question 22

What type of venom do Sac Spiders have have?

Answer 22

Cytotoxic

Question 23

Name 6 medically important spiders in Southern Africa

Answer 23

1. Six-eyed (Desert) Crab Spider (Sicarius spp)
2. Violin Spider (Loxosceles spp)
3. Sac Spider (Cheiracanthium spp)
4. Black Button Spider (Latrodectus indistinctus)
5. Brown Button Spider (Latrodectus geometricus)
6. *Small Baboon Spider (Harpactirella) But School is still out on this spider’s venom. There was a paper written many years ago that mentioned its toxicity; but since then (last 50 years) there has been no proof that this spider is any more medically important than any other Baboon spider)

Question 24

Where does the name Baboon spider come from?

Answer 24

Name derived from pads under the “feet” of these species being similar in colour and texture to the underside of a baboon’s foot (hairy bodies)

Question 25

What are paraxial chelicerae?

Answer 25

Question 26

What are setae on spiders?

Answer 26

They are very small bristle-like hairs on the feet of spiders

Question 27

How long do Baboon spiders live for?

Answer 27

Up to 20 years

Question 28

What do spiders use their palps for?

Answer 28

Males’ palps are specialised organs used during reproduction - “Lock and key system”: Male’s palp will only fit the epigynum of a female of the same species (“conspecific”)

Male deposits his sperm into a “sperm web” (spermatophore). He then “charges” his palps with this sperm and inserts it into females’ genital opening (epigynum) during copulation - In some species a section of the palp breaks off within female; ensuring no further chance of copulation with another male

Question 29

What spider is responsible for most spider bites in South Africa?

Answer 29

Long-legged Sac Spider is responsible for about 90% of all spider bites in South Africa

Question 30

What is a pedicel in spiders?

Answer 30

It connects the cephalothorax to the abdomen

Question 31

How much bigger is the female Golden Orb-Web spider than the male?

Answer 31

Up to 1000 times bigger!

Question 32

What are diaxial chelicerae?

Answer 32

Question 33

What are the characteristics of the Mygalmorph sub-order of spiders?

Answer 33

1. “Free roaming” (Which is a bit of a generalisation. Essentially they do not spin an orb web)
2. Paraxial Chelicerae
3. Two pairs of booklungs
4. Longer-lived (up to 30 years – female baboon spiders and tarantulas)

Question 34

What type of venom does the Small Baboon Spider have?

Answer 34

Neurotoxic

Question 35

What are the differences between Black and Brown Button spiders?

Answer 35

Black Button Spider

1. Red/orange marking on the dorsalside of the abdomen
2. Generally sits on top of its web
3. Has smooth; spherical egg sacs (about the size of a pea)
4. Usually black in colour (often shiny)

Brown Button Spider

1. Red/orange marking on the ventral side of abdomen
2. Generally hangs beneath its web
3. Has irregularly spiky egg sacs (similar in size to L.i.)
4. May display geometric patterns on the dorsal side of the abdomen

Question 36

How do spiders produce silk?

Answer 36

Spiders have silk-producing glands in their bodies, specifically in their abdomen. In these glands they have the chemical components already put together to produce silk, but it’s in a liquid form. When a spider wants to produce a strand of solid silk, they have to pull this strand of silk out of their bodies

Question 37

Explain the “standard” construction of a spider web?

Answer 37

There are anchor lines that do not use sticky silk. The spider will anchor these to different objects to secure the web. Sticky silk will then be spun in a circular shape around the centre of the web.

Question 38

How many baboon spiders occur in Southern Africa?

Answer 38

34 Species

Question 39

Why does the ‘daddy long legs’ vibrate when disturbed? With which venomous spider species might it be confused?

Answer 39

It’s believed that they vibrate to make their web vibrate making it more difficult for an intruder as well as it makes the spider harder to see.(???)

Question 40

What is a “Whipscorpion”?

Answer 40

A whipscorpion is an arachnid that has adapted front pair of legs that are used as sensory organs. They also have modified pedipalps used for capturing prey.

Question 41

Give another name for a Solifuge.

Answer 41

Sun Spider

Question 42

What are “spinnerets”?

Answer 42

Spinnerets are organs that spiders use to produce and spin silk into webs

Question 43

How do spiders mate?

Answer 43

The male spider will deposit some sperm on the web and will pick this up with his pedipalps and when the female is in position he will deposit the sperm in her genital opening.