Is a Brown Widow an orb weaver?

Answered by John Hunt

A Brown Widow is not an orb weaver. While both Brown Widows and orb weavers are spiders, they belong to different genera and have distinct characteristics that set them apart. In this answer, I will provide a detailed comparison between the two species to highlight their differences.

1. Appearance:
– Brown Widow: The Brown Widow spider (Latrodectus geometricus) is typically dark brown or tan in color, with a distinctive hourglass-shaped orange or yellow marking on the underside of the abdomen. The abdomen may also have various patterns of spots or stripes.
– Orb Weavers: Orb weavers, including species from the genera Neoscona and Araneus, come in a wide range of colors, such as yellow, brown, black, and even vibrant combinations. They have a round abdomen and often display intricate patterns or designs on their bodies. Some orb weavers have a cross-shaped marking on the top side of their abdomen.

2. Web Structure:
– Brown Widow: Brown Widows build irregular, tangled webs that are not classic orb-shaped. Their webs are usually found in secluded areas such as under eaves, in tree branches, or within cluttered spaces. These webs lack the typical radial pattern seen in orb weavers.
– Orb Weavers: Orb weavers are known for their large, circular, and symmetrical webs with a distinct spiral pattern created by the spider’s silk. These webs are often constructed in open spaces, such as between trees or in gardens, to capture flying insects.

3. Leg Spines:
– Brown Widow: Brown Widows have relatively smooth legs without any prominent spines. Their legs appear sleek and lack the bristly or spiky texture seen in some spider species.
– Orb Weavers: Orb weavers, as the name suggests, have spines on their legs. These spines aid in capturing and securing prey caught in their orb-shaped webs. The spines give their legs a bristly or thorny appearance.

4. Venom:
– Brown Widow: Brown Widows possess venom that is similar to Black Widow spiders but is generally considered to be less potent. While their bite can cause mild to moderate symptoms like localized pain, swelling, and redness, severe reactions are uncommon.
– Orb Weavers: Orb weavers, in general, are not known to have venom that poses a significant threat to humans. Their bites may cause minor local reactions, such as itching or redness, but serious complications are rare.

5. Geographic Distribution:
– Brown Widow: Brown Widows are native to Africa but have spread to various parts of the world, including North and South America, Asia, and Australia. They are particularly prevalent in warmer regions.
– Orb Weavers: Orb weavers are a diverse family of spiders found globally, with numerous species inhabiting different regions and ecosystems. They can be found in various climates and habitats, including forests, gardens, and grasslands.

While both Brown Widows and orb weavers are spiders, they belong to different genera and exhibit distinct characteristics. Brown Widows have a unique appearance, build irregular webs, lack leg spines, and possess venom that is generally considered less potent. In contrast, orb weavers come in various colors, build classic orb-shaped webs with leg spines, and generally have venom that is not a major concern for humans. It is essential to differentiate between these species to ensure accurate identification and appropriate response if encountered.