Special in the CRR

Whether it makes you skin crawl or delights you it plays an important role in the biodiversity of any ecosystem and is deserving of our respect and admiration.

Although the bite of some spiders can be nasty their intent is not malicious, they are merely reacting to a potential threat. For something the size of a spider just about everything that moves is substantially larger than they are and must seem pretty threatening if approaching them. Some spiders cannot harm us, others cause minimal damage, and a surprisingly low number of spiders are that dangerous that we should see them as life-threatening. 

Of the 106 spider families worldwide 64 are found in the Southern African region. This is thanks to the diversity of the regions and climate. The oldest fossilized spider in South Africa (Triassaraneus andersonorum) was found in the Drakensberg and dates back to about 225 million years ago but spiders have shown up in fossil records as far back as 390 and 360 million years ago. This was before the existence of flying insects, amphibians or even flowering plants. 

Here are some interesting facts about spiders:

They are not insects, but Arachnida. Insects have 6 legs and spiders have 8. Hairs on their body, particularly their legs are vibration receptors which help spiders to ‘hear’ since they don’t have external ears but there are also hollow ‘taste hairs’ found mostly on their legs that enable spiders to taste. Perhaps we are starting to understand why a spider needs eight legs!

Juvenile spiders must moult in order to grow, and this process enables them to grow new legs they may have lost. After each moult the newly forming leg will regenerate a little bit more. They can moult between five to nine times before becoming adults. If a leg suffers a particularly bad injury the spider can detach the leg at a particular joint and in some cases may eat the injured leg rather than detach it!

Some male spiders, like button spiders for instance are clearly determined not to share their female ‘mate’ with other male spiders. After mating they will leave a part of their palp in the female spider’s genital opening to stop other males from being able to transfer their sperm from their palpal organ which they would need to insert into the genital opening of the female. 

Not all spiders build webs. Baboon spiders for instance live in burrows lined with silk. They are nocturnal hunters and ambush their prey, often near their burrow entrance. Orb spiders on the other hand build mostly one-dimensional webs, usually in a wagon wheel design. Sitting at the hub of the web they wait for an unsuspecting insect to fly into their sticky trap. The vibrations felt through their legs let them know dinner has arrived.

Most spiders live for one to two years although some spiders reach the remarkable age of 20. 

Of course, everyone will also want to know what purpose they serve and how might their existence benefit us? You can thank them for keeping those pesky insects like mosquitos and flies at bay. Their venom however has been found through research to have great potential to develop medicines for humans, for everything from non-addictive pain medication to heart arrhythmia, neurodegenerative diseases, epilepsy and cancer. This kind of research may also produce alternatives for pest control. In short, don’t underestimate these creatures and their value to us and the natural world. 

Spiders are truly fascinating and it would be impossible to put even a fraction of what is known about them in this article, but I hope the little I have been able to share with you has made you see them in a positive light and possibly even encouraged you to pay a little more attention when you next cross a spider’s path – or web. If your curiosity has really been piqued, read Astri and John Leroy’s book on Spiders of Southern Africa, the source of most of my information, or look out for our next Scorpion and Spider Walk with Jonathan Leeming in September.