# Spinybacked Orbweaver (*gasteracantha cancriformis*) The Spinybacked Orbweaver is a fascinating and highly recognizable spider known for its distinct, crab-like appearance and colorful abdomen. Found throughout warmer regions of the Americas, this small arachnid is a welcome addition to gardens, where it acts as a natural pest controller by weaving complex, sticky webs to snare flying insects. Despite its intimidating spines, this spider is entirely harmless to humans and rarely bites unless severely provoked. Observing a Spinybacked Orbweaver in its web provides a wonderful glimpse into the intricate engineering of nature. They are particularly active during the day, making them an excellent subject for nature enthusiasts and photographers looking to spot unique wildlife. Their geometric webs are often adorned with small silk tufts, adding to their visual charm. - **Category:** [Invertebrate](https://www.snappit.app/explore/categories/invertebrate) - **Rarity:** Common - **Danger:** 1/5 · Very low - **Snaps:** 3 - **Habitat:** Found in citrus groves, hardwood forests, suburban gardens, and forest edges where they spin webs between trees and shrubs. ![Spinybacked Orbweaver](https://inaturalist-open-data.s3.amazonaws.com/photos/10541003/medium.jpg) Photo: Meghan Cassidy, CC BY-SA 4.0 · [iNaturalist](https://www.inaturalist.org/photos/10541003) ## Appearance This spider is easily identified by its broad, hardened abdomen featuring six prominent spines, typically red or black, projecting from the sides and rear. Females measure about 5 to 10 millimeters in length and 10 to 13 millimeters in width, showcasing vibrant colors like bright white, yellow, or orange on their upper abdominal surface, speckled with black spots. In contrast, males are significantly smaller, measuring only 2 to 3 millimeters, and are a drab gray or brown color without the prominent spines or bright coloration of their female counterparts. ## Taxonomy - **Kingdom:** Animalia - **Phylum:** Arthropoda - **Class:** Arachnida - **Order:** Araneae - **Family:** Araneidae - **Genus:** Gasteracantha ## Interesting facts - After mating, the male often dies shortly after, and the female dies soon after producing her single, carefully wrapped egg sac. - Only the female Spinybacked Orbweaver possesses the large, colorful abdomen with prominent spines; the males are tiny, drab, and lack notable spines. - They construct a distinctive tufted web, adding small white silk dots along the support lines to make the web visible to birds so they do not fly through it. ## Special abilities - **Aposematic Shield:** The bright coloration and sharp spines on the female's abdomen serve as a physical and visual deterrent to potential predators like birds. - **Web Vibration Sensing:** Using highly sensitive slit sensilla, the spider detects subtle vibrations in its web to pinpoint the exact location of trapped prey. - **Silk Tuft Signaling:** Adds visible tufts of white silk along its web lines to prevent birds from accidentally flying through and destroying the web. ## Measurements & details - **Length:** 0-1 cm - **Weight:** 0.00005-0.0003 kg - **Lifespan:** 0-1 years - **Clutch Size:** 100-260 - **Incubation:** 14-35 days ## Diet & Feeding Captures and feeds on small flying insects that become entangled in its strong, vertical orb web. - **Age differences:** Spiderlings consume smaller insects such as midges, while mature females target larger flies and beetles. - **Primary Foods:** Fruit flies, Mosquitoes, Moths, Beetles - **Foraging Method:** Ambush ## Ecological connections - **Eaten by:** Blue mud dauber wasp (*Chalybion californicum*) — Wasp captures this spider to provision its mud nests for its larvae. - **Hunts:** House fly (*Musca domestica*) — The spider preys on house flies that fly into its sticky web. - **Eaten by:** [Carolina Chickadee](https://www.snappit.app/explore/carolina-chickadee) (*Poecile carolinensis*) — Preys on the spider, though it may avoid larger, spiny females. ## Safety **Danger:** 1/5 · Very low No special safety notes yet. ## Frequently Asked Questions ### How to identify Spinybacked Orbweaver? Compare body proportions, leg shape, abdomen markings and the web, if there is one. Eye arrangement can be decisive but rarely shows up in a casual phone photo. A web is a supporting clue, not proof of who built it. Spider Identifier: upload a photo and compare the visible details. ### How long is Spinybacked Orbweaver? 0-1 cm ### How much does Spinybacked Orbweaver weigh? 0.00005-0.0003 kg ### How long does Spinybacked Orbweaver live? 0-1 years ### What does Spinybacked Orbweaver eat? Captures and feeds on small flying insects that become entangled in its strong, vertical orb web. ### Where is Spinybacked Orbweaver usually found? Found in citrus groves, hardwood forests, suburban gardens, and forest edges where they spin webs between trees and shrubs. ### How does Spinybacked Orbweaver hunt? Ambush ### How many eggs does Spinybacked Orbweaver lay? 100-260 ## Where to spot - [Anderson University](https://www.snappit.app/guides/places/anderson-university) — South Carolina, US · Campus - [Bok Tower Gardens](https://www.snappit.app/guides/places/bok-tower-gardens) — Florida, US · Botanical Garden - [San Antonio Missions National Historical Park](https://www.snappit.app/guides/places/san-antonio-missions-national-historical-park) — Texas, US · National Park - [Secessionville Historic District](https://www.snappit.app/guides/places/secessionville-historic-district) — South Carolina, US · Historic District - [Key West Tropical Forest & Botanical Garden](https://www.snappit.app/guides/places/key-west-tropical-forest-and-botanical-garden) — Florida, US · Botanical Garden [View all places to see Spinybacked Orbweaver](https://www.snappit.app/guides/where-to-see/spinybacked-orbweaver) ## More Invertebrate - [Coral](https://www.snappit.app/explore/coral) - [Crab Spider](https://www.snappit.app/explore/crab-spider) (*Mecaphesa asperata*) - [Garden Spider](https://www.snappit.app/explore/garden-spider) (*Araneus diadematus*) - [Brown Recluse Spider](https://www.snappit.app/explore/brown-recluse-spider) (*Loxosceles reclusa*) --- Source: [Spinybacked Orbweaver: Facts & Places to See — Snappit](https://www.snappit.app/explore/spinybacked-orbweaver)