Rain Spiders and Rain Spider Wasps

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Rain Spiders (Palystes-species)

When first confronted with the monstrously-sized Rain Spider I don’t think any person could be blamed for flinching. These arachnids can attain a leg span of up to 11cm, with their bodies alone growing to 4cm in length, and unusually for spiders both sexes are about equal in size. Their sizable fangs easily pierce human skin, but while a bite is painful and could cause a bit of swelling and itching it is not venomous.

Rain Spiders are nocturnally active predators that by nature hide and hunt in vegetation but often enters into huts and houses to prey on insects attracted by lights. It’s believed, though not conclusively proven, that finding Rain Spiders indoors is a good omen for rainfall in the days ahead. Being such formidable hunters they not only prey on other invertebrates but will even catch reptiles and amphibians.

Females may lay up to 300 eggs in large egg sacs, roughly the size of a tennis ball or even larger and constructed from leaves, twigs and silk, during the summer months. The female protects both the egg sac and newly emerged spiderlings, which hatch around three weeks after laying, and as a result it is usually gardeners that fall foul of the protective mother’s fangs when they’re out enjoying their hobby. Rain Spiders usually live for about two years.

Spiders of the genus Palystes are found in Africa, Asia and Australia. We have twelve distinct species in South Africa, of which P. superciliosus and P. castaneus are the most commonly encountered (though not easily distinguished by an untrained eye like mine).

Rain Spider, the size of a cake plate!
Rain Spider escaping the Tupperware at Bontebok National Park
Rain Spider trying to hide among dead aloe leaves at Bontebok National Park
Large Rain Spider on a dustbin at Mission Rocks
A nasty surprise hiding in the bathroom at the uMthoma Aerial Boardwalk
Rain Spider egg sac
Rain Spider egg sac
Rain Spider egg sac
Rain Spider curled up in self-defense
Rain Spider curled up in self-defense

Rain Spider Wasp (Tachypompilus ignitus)

The Rain Spider Wasp is a specialist hunter of Rain Spiders occurring in South Africa and Zimbabwe. When hunting, the female wasp paralyses the spider with a sting and then carries it’s victim to its nest where an egg is laid on the spider before the nest is sealed up. When the wasp larvae hatches it feeds on the still living spider, keeping the vital organs for last so that the spider can be a source of fresh food as long as possible. Once its larder is used up, the larvae pupates and emerges as an adult wasp – which feeds innocently on nectar. Rain Spider Wasps themselves are quite large and adults measure almost 5cm in length.

Rain Spider Wasp (Tachypompilus ignitus)
Rain Spider Wasp (Tachypompilus ignitus) photographed by Joubert
Rain Spider Wasp (Tachypompilus ignitus)

28 thoughts on “Rain Spiders and Rain Spider Wasps”

    1. de Wets Wild Post author

      Amazing how the tables turn in this instance, John, that a spider the size of cake plate can fall prey to a wasp much, much smaller than itself when one would’ve expected the spider to snack on the wasp instead!

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    2. Andrea Jordaan

      I had the lucky experience of witnessing this process: I was in the pool nd spotted a smallish rain spider floating in the pool so I gathered all my guts (I am terrified of spiders) and scooped the poor thing out onto the bricks thinking it fell in by accident. To my surprise one of those wasps appeared stung the what I now realise was a paralysed spider again and dragged it back to the edge of the pool and dropped it in again! After a minute or two the wasp retrieved the spider and pulled it up out of the pool and proceeded to drag it off into the undergrowth in the flower bed. I unfortunately didn’t have my camera nearby so couldn’t film or capture the event but it is the first tme i have ever felt sorry for rain spider.

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  6. Writer Lori

    Wow, my skin crawled just reading this post. I am not a fan of spiders. We have something called a Wolf Spider here in Florida. Not venomous, thankfully, but quite large and hairy. Quite intimidating…

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  7. Anne

    We have had a large rain spider standing sentinel on a wall in our lounge for a few days – fine while it is visible; not so fine when it disappears – where will it turn up? They are fairly common here and I sometimes come across the skins they have shed – these can look fairly menacing until one realises they are empty 🙂

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  9. Ally's Bush Tales

    That was a very interesting read. I grew up terrified of spiders but spending long periods in the Bush is starting to cure me of my horror. Slowly 😊. Found the part about the wasps really fascinating. Felt sorry for the spiders actually!

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  10. H.J. for avian101

    When I was just a child, I used to avoid the arachnids but then later I lost the fear for them. I’ve seen plenty of them in the Amazon Rainforest. Have you noticed that even a small child that never saw one spider before when shown a live spider, the tot will fear it? I think they can signal the human with a fear alarm that triggers danger. Frogs have certain colors that mean poison. Just my idea. Thanks for the post, D. 🙂

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    1. de Wets Wild Post author

      I think you’re right, H.J. The instinct to fear spiders and snakes, especially, is probably something that evolved long before humans looked like we do today. Just think what could have lived in those caves we used to dwell in!!

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  12. sustainabilitea

    Hmmmm, very interesting, especially in the way the two interact. I’m not sure I’d like to run into a spider that size even knowing it’s not venomous. I do love spider webs, though, particularly when covered with dew or rain drops and backlit by sunshine. Can’t have those without spider, can I? 🙂

    janet

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    1. de Wets Wild Post author

      You’re quite right, Janet – a spider wen truly is one of the most splendidly beautiful things in nature, despite the intent behind it! These spiders won’t present you with a delightfully crafted piece of weaving though – they prowl on the hunt!

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