05 Aug Eight-legged wonders
Spiders. Painted as the freakish fanged eight-legged beasts spinning webs to ensnare unsuspecting victims, these arachnids really do get a bad rap. Whether its giant spiders in Harry Potter and Lord of the Rings or their eerie Halloween associations, mankind generally finds spiders fit only for a good stomping on. So scared are we that up to 6% of the global human population has arachnophobia, a debilitating fear of spiders, and in 2019 it was listed as the number one phobia globally. The truth is spiders are misunderstood and learning about them is key to facing these fears!
Lucky for us in 2016 our very own Gregory Canning, the Welgevonden Volunteer Research Coordinator, undertook to study Welgevonden spiders, particularly the impact of fire on spider communities, for his PhD. Greg, with help from research assistants and volunteers, sampled spiders across the Reserve by setting pitfall traps, beating trees and sweep netting in grass to make sure they covered all habitat types and collected a whopping 4816 spider specimens! After a painstakingly long sorting and identification process, 345 species from 43 different families were identified and recorded on the Reserve. Twenty-three of these were new species recorded for the Waterberg region. Here are some interesting things we learned about the families and species that occur here.
Greg and team found three species of spiders from the Uloboridae family. This is one of only two families in the entire world that do not have venom or venom glands which makes them quite unique. Spitting spiders also occur here and are the only spiders known to possess glands in their carapace that produce venom and a gluey silk which is mixed together and squirted over their prey from their chelicerae (mouthparts), rather than their abdomen. Once a spitting spider locates its prey, it will tap on the ground and manoeuvre around the target to get an idea of its position (they have poor eyesight) before unleashing the sticky concoction from alternating fangs in a zig-zag pattern, pinning the prey in a sturdy net to the surface. In the words of the Terminator, “Hasta la vista, baby!”
The most diverse group of spiders on Welgevonden, which reflects their status in South Africa, is the jumping spider family with 61 species, all of which are harmless to humans. Baboon spiders, or tarantulas as they are called in other parts of the world, are found here and are all protected species. Surprisingly, very little is known about South Africa’s baboon spiders as they are very seldom seen, usually only in late summer, when the males leave their burrows in search of females. They are long-lived spiders (some females live up to 15 years!) and are under threat from habitat destruction and over-harvesting for the illegal pet trade. If you happen to see one, take a photo and submit it to the baboon spider atlas here, to help scientists learn more about their distribution.
At lodges, you should look out for flower crab spiders, these sit-and-wait predators lurk amongst the petals waiting for a chance to pounce on unsuspecting insect pollinators. These well camouflaged, harmless spiders range from white to bright yellow and pink, and various patterns thereof. Certain species can even change colour! You should also keep your eyes peeled for hairy field spiders making their webs in the evenings between branches or walls, only to remove the web in the morning, hide for the day and emerge at dusk to start all over again. These spiders resemble bark spiders, which may also be found around homes, and display the same web building behaviour.
Although most spiders envenomate their prey, because of their small size most spider venom has little effect on humans. So, while they might be deadly killers in their small-scaled world, to us they just cause skin irritations or mild allergic reactions. Very few spiders in South Africa are considered of medical significance to people. Both brown and black button spiders occur here on the Reserve and despite their fearsome reputation they are extremely reluctant to bite, are very inoffensive and often play dead when threatened. Violin and six-eyed sand spiders belong to the same family and are rare, free roaming spiders. Violin spiders are occasionally found in homes, but the sand spiders are generally only encountered when actively looking for them. They regularly bury themselves under sand where they can spend long periods of time. No bites from sand spiders have been confirmed but laboratory tests indicate their venom is possibly medically significant.
These are just a few of the fascinating species we share the Reserve with, there are many more (access the spider list here). Perhaps, instead of worrying about how many spiders we swallow in our sleep, we should take a deep breath in, let go of our fear and learn more about our eight-legged friends and the amazing lives they lead. Better yet, when you visit us, ask your guides about them – they are after all just little lions.
If anybody would like spiders identified or just any general information please contact Greg at gregory@welgevonden.org
Photos Top – Bottom: Common garden orb spider, Banded legged golden orb spider, Green pea spider, Decorated nursery web spider (©Margerie Aucamp & ©Carmen Warmenhove)
