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Spiny Orb-Weaver (Gasteracantha)

The spiny-orb weaver is an orb-weaving spider known for its unique spiny abdomen. Found across Asia, America, Africa, and Australia, this spider is recognized by its distinctive look. On this page, you’ll discover interesting facts about this fascinating creature.

Table Of Content hide

List of Spiders Belonging to the Genus

Physical Description and Identification

Are Spiny Orb-Weaver Spiders Venomous?

Can Spiny Orb-Weaver Spiders Bite?

Ecological Importance and Behavior of Spiny-Orb Weaver

Quick Facts

Did You Know

List of Spiders Belonging to the Genus

G. aciculata	G. clavatrix	G. diardi
G. acutispina	G. clavigera	G. doriae
G. audouini	G. crucigera	G. falcicornis
G. aureola	G. curvispina	G. fasciata
G. beccarii	G. curvistyla	G. flava
G. biloba	G. cuspidata	G. fornicata
G. cancriformis	G. dalyi	G. frontata
G. clarki	G. diadesmia	G. gambeyi
G. geminata	G. hasselti	G. hecata
G. interrupta	G. irradiata	G. janopol
G. kuhli	G. lepelletieri	G. lunata
G. martensi	G. mediofusca	G. mengei
G. metallica	G. milvoides	G. notata
G. panisicca	G. parangdiadesmia	G. pentagona
G. picta	G. quadrispinosa	G. recurva
G. regalis	G. remifera	G. rhomboidea
G. rubrospinis	G. rufithorax	G. sacerdotalis
G. sanguinea	G. sanguinolenta	G. sapperi
G. sauteri	G. scintillans	G. signifera
G. simoni	G. sororna	G. sturi
G. subaequispina	G. taeniata	G. theisi
G. thomasinsulae	G. thorelli	G. tondanae
G. transversa	G. unguifera	G. versicolor
G. westringi

Physical Description and Identification

Adults

Size: The females have a length and width of 5-9 mm and 10-13mm respectively. The males are smaller in size, being 2-3mm in length and a little more in terms of width.
Color: They are bright in color, having a yellow, white, or orange abdomen with markings of red. The spiny projections as mentioned below are red or orange, while those of the males are of a darker shade.
Other Characteristic Features: They have six spiny projections protruding at the backside of the abdomen. The large spiny projections are mainly present in the female spiders of this genus, while for the males they look like small humps, being five to six in number.

Eggs

The egg sac has about 100 to 260 eggs which hatch in 11 to 13 days. When laid on a silken sheet they are protected with a white or yellow spongy, tangled, loose mass.

Spiderlings

They remain in the silken case between two and five weeks and become dark in color on acquiring maturity.

The Web

They are known to build large-sized circular webs like most other orb-weavers for capturing prey.

Are Spiny Orb-Weaver Spiders Venomous?

Yes, spiny orb-weaver spiders are venomous, but their venom is not harmful to humans.

Can Spiny Orb-Weaver Spiders Bite?

Spiny orb-weaver spiders can bite, but it’s rare. If they do, it’s usually painless and not dangerous to people.

Ecological Importance and Behavior of Spiny-Orb Weaver

Spiny-orb weavers play a pivotal role in controlling insect populations, particularly moths, flies, mosquitoes, and beetles, aiding in the maintenance of ecological balance. Their complex webs not only serve as effective tools for capturing prey but also contribute to the aesthetic beauty of their natural habitats. During the day, these spiders tend to hide, showcasing nocturnal behavior as they engage in hunting and web maintenance.

Natural Predators and Prey-Predator Dynamics: Birds and larger insects often pose a threat to the spiny-orb weaver. Their webs, while delicate and beautiful, are also their line of defense, creating a complex dance between predator and prey in the wild.

Relationship with Humans: Commonly found in woodlands, shrubby gardens, nurseries, and citrus groves, the spiny-orb weaver is a familiar sight for many. Despite their venomous nature, they are harmless to humans, contributing positively to our environment by keeping insect populations in check.

Quick Facts

Other Names	Spiny-backed orb-weavers, star spider
Distribution	Parts of Asia (Indonesia, Malaysia, Thailand, Philippines, China, India, Sri Lanka); Africa, Australia and United States
Habitat	Woodlands, shrubby gardens, as well as nurseries, and citrus groves
Diet	Moths, flies, mosquitoes, and beetles

Did You Know

Swedish zoologist, Carl Jakob Sundevall was the first to have described this species in the year 1833.
Though their abdomen resembles a crab shell because of the spikes present in the abdomen, one should not confuse them with crab spiders.

In conclusion, the spiny-orb weaver is a mesmerizing specimen within the arachnid world, boasting unique physical characteristics, playing a crucial role in our ecosystems, and maintaining a generally benign relationship with humans.

Frequently Asked Questions

What does a female spiny orb-weaver look like?

A female spiny orb-weaver has a brightly colored abdomen, which can be yellow, white, or orange with red markings. Its most defining feature is the six prominent, sharp spines protruding from its back. The body is notably wide, measuring 10-13 mm across, giving it a distinct crab-like appearance.

How big do spiny orb-weaver spiders get?

Spiny orb-weaver spiders show significant size differences between sexes. A mature female measures 5-9 mm in length and 10-13 mm in width, making her appear broad. In contrast, the male is much smaller, typically only reaching 2-3 mm in length with a slightly greater width.

Are male and female spiny orb-weavers different?

Yes, male and female spiny orb-weavers are visually distinct, a trait known as sexual dimorphism. Females are larger, more brightly colored, and possess six large, sharp abdominal spines. Males are smaller, have darker coloration, and their abdominal projections are reduced to five or six small humps.

How many eggs does a spiny orb-weaver lay?

A female spiny orb-weaver typically lays between 100 and 260 eggs in a single egg sac. She constructs this sac from silk and often attaches it to the underside of a leaf near her web. This placement helps protect the developing eggs from predators and environmental exposure.

How long does it take for spiny orb-weaver eggs to hatch?

Spiny orb-weaver eggs hatch approximately 11 to 13 days after they are laid. However, the spiderlings usually remain inside the protective silken egg sac through the winter. They emerge in the spring when temperatures become more favorable for their survival and dispersal to build their own webs.

What colors are spiny orb-weaver spiders?

Spiny orb-weaver spiders are known for their vibrant and varied coloration. Their abdomens are typically a base of white, yellow, or orange and are often decorated with red markings. The characteristic spines that protrude from the abdomen are usually a contrasting red or orange, making them highly visible.

Why is it called a spiny orb-weaver?

The name spiny orb-weaver directly describes its two most notable features. The term “spiny” refers to the six hard, sharp projections on its abdomen, which are especially prominent on females. “Orb-weaver” describes its behavior of constructing the classic, round, wheel-shaped webs used to capture flying insects.

Spiny Orb-Weaver (Gasteracantha)

List of Spiders Belonging to the Genus