From the cute to the colossal: Plant-dwelling spiders of Renosterveld

From the cute to the colossal: Plant-dwelling spiders of Renosterveld

Above: Crab Spider on a Moraea inconspicua

Some plant-dwelling spiders are only 3mm in size, and are considered the ‘cuties’ of the spider world. Take a close look at their very endearing eyes, which make them particularly gorgeous subjects for macro-photography.

Above: Crab Spider with fly prey

Other plant dwellers include the Rain Spiders, the large spiders that often creep into your house before it rains. Despite their size, don’t be frightened of this species: they are shy, and would much rather run away than hurt you. Join me in getting to know some of the plant-dwelling spiders of Renosterveld.

PLANT DWELLERS

Oxyopidae: Lynx Spiders

This is a small genus with a global distribution. They do not make use of webs or retreats, although some species will hang from a dragline attached to the underside of a leaf. These beautiful spiders received their common name because of the way they hunt: they often catch prey with their legs by jumping into the air and catching insects in full flight.

Some genera are limited to living on a single plant species, others may have adaptations, such as long hairs (setae) on their legs, to enable them to blend in with the spikey grasses on which they hide in wait of passing prey. The female does not carry her egg sac around, but instead fastens it to a twig or leaf, where she guards and defends it.

Above: Lynx Spider, Oxyopes sp.

Above: Lynx Spider

Salticidae: Jumping Spiders

Some of my favourites, the ‘cuties’ of the spider world, are the Jumping Spiders, belonging to the family Salticidae (hence known affectionately as ‘Saltis’ by spider fans), the largest family of spiders in the world, with over 350 species (and counting!) known from South Africa. They vary in size from 3 to 17mm and are active hunters. Some have particularly noticeable bristles in the eye region, giving the impression that they have long ‘eye-lashes’, thus making them extremely endearing. They often move fast and can be difficult to photograph but make beautiful subjects for macro-photography.

Above: Jumping Spider or ‘Salti’ Thyene inflata eating eggs, mostly likely belonging to an insect. 

Above: Jumping Spider, Baryphas ahenus

Above: Jumping Spider, Rhene konradi

They do not make webs, but they do build nests in which to moult or lay eggs. They may even make use of such nests to mate or simply as a retreat during times of inactivity. The Jumping Spiders are in fact divided into three groups: hoppers, runners and intermediates. They are diurnal hunters with two noticeably large eyes (the other six are smaller) with complex retina which gives these incredible creatures unique resolution abilities found in no other animal of equivalent size. They detect and capture prey by means of stalking, chasing, leaping and lunging (or a combination of these methods).

Above: Jumping Spider Langelurillus namibicus, a very rare and poorly documented species in SA. 

Above: Jumping Spider, Evarcha denticulata

Above: Jumping Spider, Dendryphantes sp.

Above: Jumping Spider, Heliophanus sp.

Above: Jumping Spider, Menemerus sp

Sparassidae: Huntsman & Rain Spiders

This is a family of free-living spiders, most of which are found on foliage, while a smaller proportion of them live on the ground. They do not make webs, but some make use of a silk-lined retreat or burrow in which to hide when not active. Most of the species in this group are active, nocturnal hunters. The ‘Rain Spiders’ Palystes spp. are the most encountered in houses, where they often appear a day or two before it rains (hence their common name); they come inside to hunt by making use of the lights which attract insects. They are one of our largest spiders and are well-known for the large, cocoon-like egg sacs which they construct amongst the vegetation.

These spiders tend to strike fear into people, mostly because of their size, but like all spiders, these are shy and do not want to bite. They will, however, raise their front legs in warning if they feel threatened and if taunted further, may bite (their bite is painful, but not medically significant). The smaller and very beautifully marked Arid Rain Spiders Parapalystes sp. are the most commonly-encountered in Renosterveld.

Top left: Typical rain spider nest. Top right and above: Palystes or Parapalystes sp.

Above: Palystes sp., gravid female

Thomisidae: Crab Spiders

This large and diverse family is made up of free-living spiders, most of whom are found on plants, with only a small number living on the ground. These attractive spiders come in a variety of patterns and colours (from bright colours such as pinks, green and yellows to white, dark brown or grey). They do not make webs or retreats but hide under vegetation or debris when not active.

Above: Crab Spider, Oxytate sp.

Crab Spider, left: Monaeses cf.pustulosus, right: Thomisus citrinellus with bee prey

They have evolved as expert ambushers and as a result have lost their agility and become sedentary, mostly moving with a sideways gait. This gait, combined with their two longer sets of front legs and their almost comical stance is responsible for them receiving their common name ‘Crab Spider’. The most frequently encountered genus in Renosterveld is Thomisus, the brightly coloured Crab Spiders which can change their colour to that of the flower from which they are ambushing prey, enabling them to surprise and capture unsuspecting flies and bees which visit the flowers.

Above: African Mask Crab Spider, possibly Synema sp.

Trochanteriidae: Scorpion Spiders

These spiders look a lot scarier than they are; they are free-living wanderers, found under bark or stones. They do not build webs or retreats. Very little is known about these unusual spiders whose flattened bodies are an adaptation to living in narrow crevices. As intimidating as they might appear, Scorpion Spiders are not medically significant.

Above: Scorpion Spider, Platyoides sp.

ACKNOWLEDGEMENTS

I would like to thank you National Lotteries Commission of South Africa for their assistance with the purchase of additional camera equipment to support the ORCT’s photographic work. A big thank you to Astri Leroy for checking this piece for correctness and teaching me a lot! My sincerest thanks to the Spider Club of South Africa for their fantastic Facebook page, led by a group of passionate spider experts and members who are only too willing to give of their time to identify photographs and answer peoples’ questions. I highly recommend joining this club and / or following them on Facebook: www.spiderclub.co.za or Facebook: @theSpiderClubOfSouthernAfrica.

Visit the National Lotteries Commission (NLC) website to find out about other projects supported by the NLC.