Are Spiny Orb-Weaver Spiders Poisonous?

The Gasteracantha (a.k.a spiny spiders, spiny orb-weavers, or spiny-backed orb-weavers) are in the orb-weaver genus of spiders. The spiders have unique spikes on their backs. Are Spiny Orb-Weaver Spiders Poisonous?

The female Gasteracantha have brightly-colored spines on their shell-like, hardened, and broad abdomens. However, are spiny orb-weaver spiders poisonous? 

The simple answer is, NO, Spiny Orb-Weaver Spiders are not poisonous. While these Gasteracantha spiny spiders can bite, they aren’t aggressive or poisonous spider species and they won’t trigger any grave symptoms on humans. 

Detailed: Are Spiny Orb-Weaver Spiders Poisonous?

Spiny Orb-Weaver Spiders measure about 1/4″ – 1/2″, have 8 legs and are yellow, orange, black, or white in color with red markings. If you notice the colorful spiders and some large spun webs, then it may be a sure sign that your yard has been infested by spiny orb-weaver.

The spiny orb-weaver will mainly make their nests on shrubs, citrus trees, or around the sides of your house. In addition, these insects will mainly be active from October to January where they’ll produce oval egg sacs under man-made structures and tree leaves too – interestingly they do this next to the webs by their females counterparts.

Each eggs sack of this Spiny Orb-Weaver Spiders will hold roughly 100 – 300 eggs, and thus its presence will definitely signify a massive infestation in your yard. Sadly, the eggs will hatch within 2 weeks and hence you must control the bugs before the begin their hatching and reproduction.

How to identify the Spiny Orb-Weaver

The bug’s body color is the surest way to distinguish between the spiny-back species – particularly in this case the orb-weaver spiders.

The male orb-weaver spiders are largely smaller compared to their female counterparts – their body length ranges from 2 – 3 millimeters but slightly longer in body width. On the other hand the female orb-weaver spiders measure 5 – 9 millimeters in body length and their body width is 10 – 13 millimeters.

Source: Wikipedia

The spiny spiders, just like name mentions, have 6 ‘spines’ or projections protruding from the rear of their abdomen. You’ll find bright color on the dosaum or top of the spiny spiders’ abdomen – these will be red spines plus black spots on the white background.

However, some of the spiny spiders, may be yellow but have black spikes. But other may also be completely black in color. The male bugs will have 4-5 small humps while their females come with large spines sitting on their back of their body.

Special Behaviors by the Spiny Orb-Weaver

The Micrathena and Gasteracantha genus are the most prevalent among these spiders – particularly considering their body patterns, shape and colors. The Gasteracantha cancriformis males are tinier while the female adults are about half an inch. 

With their spine-like spines, crab-shaped and compact bodies makes these Spiny Orb-Weaver Spiders look very distinctive. Geographically, the color of the female Spiny Orb-Weaver Spiders is different because the black-spot abdomens could be yellow or white.

Further, the spines or projections might be black or red. Further, their male counterparts may have abdomens that are gray, small spines, and white spots. However, these spiders look like they’re dwarfed by their circular and spreading snares. So, simply spot any spider webs at your eye-level and above particularly on shrubs, trees, and buildings.

One unique characteristic of the Spiny Orb-Weaver Spiders is that you’ll note some silk tufts around the house – especially around its foundation lines. The silk turfs act to protect the spider’s eggs and babies from humans, other animals and birds. However, the silk tufts may also attract some prey or even caution lizards.

Generally, the female Spiny Orb-Weaver Spiders in the Araneidae family are considered web builders. Further, the females will mainly work to rebuild and repair the spider webs – they’ll do this in a single location if they won’t be disturbed. The remaining time, the females will sit waiting for any predator from which they’ll such the animal’s bodily fluids. 

Habitat and Food: Spiny Orb-Weaver Spiders live?

Habitat: You’l mainly find these bugs in southern states particularly Florida or southern California but they’ll also inhabit different regions in the world.

As noted earlier, you’ll mainly find these Spiny Orb-Weaver Spiders in residential places plus citrus groves, around houses, shrubs and trees near your house. You’ll notice them from their color and the webs they create plus you might notice their eggs sacs.

Food: On diet, the Spiny Orb-Weaver Spiders mainly feed on small insects that they’ll capture using their intricately made webs.  Specifically, the bugs will feed on small insects such as flies, mosquitoes, beetles, and moths. The spiders will bite and paralyze the insects as they feed on their ovals.

Controlling Spiny Orb-Weaver Spiders

Since the spiders mainly feed on insects, it makes sense to reduce the amount of light that’s particularly outside your house – this will keep the spiders away plus also discourage their small insects from coming near your yard and house too.

Therefore, I suggest you change the exterior lights and install ‘bug lights’ that are particularity yellow in color as this will reduce the amount of light and hence the number of small insects that’ll be flying near your yard or house in the evenings and at night.

Further, ensure that you clean and clear all the webs that are around the house as this will discourage the spiders from creating their webs. You might require to undertake more aggressive bugs control measure if you’re having a massive Spiny Orb-Weaver Spiders  infestation – this may include finding the eggs sacs and bug webs.

For this, I would recommend using ‘de-webbing’ substances – particularly those that are organic as these will help prevent the spider webs from easily attaching on the house or bushes around the yard or lawn. This ensure that the spiders won’t get a habitat from where they’d hatch a re-infestation in your residence.

However, on the extreme case of infestation by the Spiny Orb-Weaver Spiders, simply hire the services of a professional exterminator to control the bugs. Such services might be costly but its definitely worth it as it immidietly takes the burden off your shoulders.


So, are Spiny Orb-Weaver Spiders Poisonous? Well, as I’ve outlined above, these spiders can bite humans but they aren’t aggressive or poisonous. However, the spiders will only bite when they’re provoked as these are generally beneficial bugs in your farm or yard.

Definitely, the bites from these Spiny Orb-Weaver Spiders won’t be poisonous as won’t also cause any grave or dangerous symptoms on you body.

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