The yellow sac spider indigenous to Americas was initially a part of the Clubionidae and Miturgidae groups but at present belongs to the Eutichuridae family.
Size: The females are 0.20 inches to 0.35 inches (5mm to 9 mm), while the males have a length of 0.15 inches to 0.31 inches (4mm to 8 mm).
Color: It has a pale yellow-beige body, while its palps, jaws and tip of the feet have markings of brown or black (which have earned it the name black-footed spider). There is also an orange brown stripe running through the top-centre part of its abdomen.
Females produce about two egg sacs in general that may even go up to five, with each sac containing approximately 30 to 50 eggs. Laid in small silk tubes, the eggs are small and round-shaped, covered in white silk, deposited at the bottom of the leaves or other foliage. The mother spider stays with the eggs and shields them against any predator.
Approximately 40 spiderlings hatch from a single sac mostly in spring. The juvenile spiders remain the silken sac for a while after birth before being on their own completely. The mother spider stays with the spiderlings for approximately seventeen days, till they complete the first molt.
The Yellow sac spider does not make webs, rather they build a sac or silken tube in protected places like beneath a leaf or at the meeting point of a ceiling and wall.
The yellow sac spiders are venomous and their bites are said to contain cytotoxin, resulting in necrosis (cell injury where the cells in the living tissues die prematurely). However, this necrotic nature of the bite of this spider has been a subject of dispute. In fact, in one study conducted in Australia and the United States, it was seen that out of the 20 people bitten by this species, none of the bites had been of a necrotic nature.
There have also not been any reports of fatalities in humans from the bites of these spiders. Besides moderate pain, other common symptoms that the victim might suffer from include localized swelling and itching, while some could also encounter feelings of nausea and dizziness.
The bite of these spiders look like a red welt and are often mistaken for that of a brown recluse, though the sting of the latter can be more painful and severe.
Though the symptoms go away between seven and ten days, in case of severity a medical practitioner’s help needs to be sought. Some normal home remedies people mention include applying an ice pack and hydrogen peroxide on the affected area.
| Other names | American yellow sac spider, Black-footed yellow sac spider, Northern Yellow sac spider |
| Lifespan | Males: 1 year; Females: 2 years or a little more |
| Distribution | Parts of the New World (Northern, Southern and Central America as well as the West Indies) |
| Habitat | Underground debris, forest floors, trees, fruit orchards as well as several manmade structures |
| Diet | Their own eggs, other spiders bigger than their own size as well as a variety of insects |
Image Credits: Cdn.securesyte.com, Farm3.static.flickr.com, Forestryimages.org, Bugguide.net, Taeniatec.com, Creationwiki.org,
Farm5.staticflickr.com, Usaspiders.com
The yellow sac spider indigenous to Americas was initially a part of the Clubionidae and Miturgidae groups but at present belongs to the Eutichuridae family.
Size: The females are 0.20 inches to 0.35 inches (5mm to 9 mm), while the males have a length of 0.15 inches to 0.31 inches (4mm to 8 mm).
Color: It has a pale yellow-beige body, while its palps, jaws and tip of the feet have markings of brown or black (which have earned it the name black-footed spider). There is also an orange brown stripe running through the top-centre part of its abdomen.
Females produce about two egg sacs in general that may even go up to five, with each sac containing approximately 30 to 50 eggs. Laid in small silk tubes, the eggs are small and round-shaped, covered in white silk, deposited at the bottom of the leaves or other foliage. The mother spider stays with the eggs and shields them against any predator.
Approximately 40 spiderlings hatch from a single sac mostly in spring. The juvenile spiders remain the silken sac for a while after birth before being on their own completely. The mother spider stays with the spiderlings for approximately seventeen days, till they complete the first molt.
The Yellow sac spider does not make webs, rather they build a sac or silken tube in protected places like beneath a leaf or at the meeting point of a ceiling and wall.
The yellow sac spiders are venomous and their bites are said to contain cytotoxin, resulting in necrosis (cell injury where the cells in the living tissues die prematurely). However, this necrotic nature of the bite of this spider has been a subject of dispute. In fact, in one study conducted in Australia and the United States, it was seen that out of the 20 people bitten by this species, none of the bites had been of a necrotic nature.
There have also not been any reports of fatalities in humans from the bites of these spiders. Besides moderate pain, other common symptoms that the victim might suffer from include localized swelling and itching, while some could also encounter feelings of nausea and dizziness.
The bite of these spiders look like a red welt and are often mistaken for that of a brown recluse, though the sting of the latter can be more painful and severe.
Though the symptoms go away between seven and ten days, in case of severity a medical practitioner’s help needs to be sought. Some normal home remedies people mention include applying an ice pack and hydrogen peroxide on the affected area.
| Other names | American yellow sac spider, Black-footed yellow sac spider, Northern Yellow sac spider |
| Lifespan | Males: 1 year; Females: 2 years or a little more |
| Distribution | Parts of the New World (Northern, Southern and Central America as well as the West Indies) |
| Habitat | Underground debris, forest floors, trees, fruit orchards as well as several manmade structures |
| Diet | Their own eggs, other spiders bigger than their own size as well as a variety of insects |
Image Credits: Cdn.securesyte.com, Farm3.static.flickr.com, Forestryimages.org, Bugguide.net, Taeniatec.com, Creationwiki.org,
Farm5.staticflickr.com, Usaspiders.com
James Lambrou on February 22, 2019.
Dr. Watuwa James
© 2023 (Spider Identifications). All rights reserved. Reproduction in whole or in part without permission is prohibited.
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