Micro Predators – Golden Orb Spiders

Most southern African Safaris focus on game viewing of the African 'Big Five'

For the majority of visitors to South Africa going on their first safari, most would like to tick off the ‘Big Five’ on their checklist. Next on the list would be to watch the hunt and kill by a feline predator. While these are awesome sightings, they do however detract from the sheer diversity of natural wonders easily seen throughout the country.

A stroll through the fynbos can reveal some amazing micro predators displaying their agility while securing a meal.

Golden Orb Spiders are renowned for their distinctive webs.

The Golden Orb Spiders are worth watching. Spinning webs with silk that is included in the category of the top three strongest biomaterials (Limpet ‘teeth’ and Mussels byssus fibers are the other two), their webs are a distinctive yellow to golden colour. It is while watching a Golden Orb secure her prey after it gets caught in her web that the precision of web spider’s hunting is fully appreciated.

First the spider 'casts' a silk net to secure the preys legs to reduce the chance of injury.

Rushing in to secure a grasshopper, a Golden Orb approaches to within 2cm of the grasshopper, points her spinnerets at it and fires three steams of multi strand web like a cast net. The silk immobilizes the grasshopper legs and the spider moves in closer to wrap up her meal.

Once the preys legs are secured the spider moves in closer and uses her rear legs to comprehensively cloak it in a cocoon of silk.

Still secreting silk, she uses her back legs to wrap up the prey. She then moves back and waits till the preys struggles reduce.

Delivering the final toxin filled bite.

When the struggling vibrations calm down she approaches again and bites the prey, injecting a concoction of neuro, cyto and heamo toxins.

As part of their survival strategies, spiders have a prey size recognition pattern which prevents them from worrying about very small prey (too small and they are unable to recoup the energy required to wrap and kill it) and avoiding large prey, the latter of which could injure the spider.

In this sequence of photos the Golden Orb secured the grasshopper without injury, but when attacking a second grasshopper, it managed to kick her and break her left rear leg. She secured it before retreating to lick her wounds.

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