The spider family Clubionidae (sac spiders) includes around 581 described species (Platnick 2013). Around 58 of these occur in North America north of Mexico (Bradley 2013). Clubionids are wandering hunters and do not build webs to capture prey, although they do make sac-like silken retreats, often in rolled leaves, for molting and for depositing egg sacs. Clubionids are mostly medium-sized, light-colored spiders that are active at night. They occur on foliage, beneath loose bark, in leaf litter, and under rocks (Edwards 1958). The common name "sac spider" is derived from the fact that they build a compact silk retreat each morning before becoming inactive until the evening (Bradley 2013). Like most spiders, clubionids have eight eyes.
Historically, a broad range of spiders with two tarsal claws have been included in the Clubionidae. A number of families formerly treated as subfamilies within Clubionidae are now treated as distinct families and several genera formerly included in the Clubionidae are now placed in families that were always considered distinct from the Clubionidae. Some issues related to the delineation of this family remain, however, such as whether Cheiracanthium is a clubionid or, instead, belongs in the family Miturgidae (Richman and Ubick 2005 and references therein). The Nearctic clubionids were revised by Edwards (1958) although there have been a number of additions since then (see Richman and Ubick 2005 and references therein). Clubionids can be distinguished from similar-looking spiders in the family Gnaphosidae by their conical spinnerets. In clubionids, these are arranged in a compact cluster that rarely extends beyond the end of the abdomen. In contrast, gnaphosids have conspicuous cylindrical spinnerets, which are often visible from above. (Bradley 2013)
- Bradley, R.A. 2013. Common Spiders of North America. University of California Press, Berkeley.
- Edwards, R.J. 1958. The spider subfamily Clubioninae of the United States, Canada and Alaska (Araneae: Clubionidae). Bulletin of the Museum of Comparative Zoology 118(6): 363-436.
- Platnick, N. I. 2013. The world spider catalog, version 14.0. American Museum of Natural History, online at http://research.amnh.org/entomology/spiders/catalog/index.html
- Richman, D.B. and D. Ubick. 2005. Clubionidae. Pp. 77-78 in D. Ubick, P. Paquin, P.E. Cushing, and V. Roth (eds.) Spiders of North America: an Identification Manual. American Arachnological Society.
This family of spiders is found all around the world, and about 540 species are known. Only about 30 species are found in Michigan.
Biogeographic Regions: nearctic (Native ); palearctic (Native ); oriental (Native ); ethiopian (Native ); neotropical (Native )
Sac spiders are medium sized (5-12 mm body length) pale spiders. Like all spiders they have two body-segments, a cephalothorax in front and an abdomen behind. They have eight legs, all attached to the cephalothorax. The legs are fairly long in this family, often twice as long as the body.
On the front of the cephalothorax they have two small "mini-legs" called pedipalps. These are used to grab prey, and they are used in mating. Pedipalps are much bigger in male spiders than in females. In this family all species have eight eyes in two rows of four. Their eyes are small and all the same size, though back row eyes are sometimes oval-shaped and longer than the front row. These spiders have strong mouthparts and their fangs are sometimes a bit longer than other spiders of the same size. All sac spiders have venom glands.
Sac spiders are often rather pale: a common house species is yellowish white, some are even lighter and others are light brown. No matter how pale they are, their mouth parts and the area near their eyes is much darker, usually dark brown.
Range length: 5.0 to 12.0 mm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
These spiders climb around on vegetation looking for prey. They can be found in most habitats that have lots of plants. A few species in this family are often found in houses and other buildings.
Habitat Regions: temperate ; tropical ; terrestrial
Terrestrial Biomes: taiga ; chaparral ; forest ; rainforest ; scrub forest
Wetlands: swamp ; bog
Other Habitat Features: urban ; suburban ; agricultural
Sac spiders are aggressive hunters. They search vegetation at night, grabbing, biting, and eating the Insecta and other invertebrates they find there.
Sac spiders spin a little silken room to hide in during the day. Sometimes they fold a leaf over and spin in there, sometimes they hide under a stick or a stone. They are only active at night, so they are hard to see. They will bite to defend themselves if they can.
- other Araneae
Life History and Behavior
Communication and Perception
Since they are active in the dark, these spiders mostly rely on smell, touch, and taste for communication. They can see, but not very well.
Spiders hatch from eggs. The hatchlings look more or less like grown-up spiders, though sometimes their colors change as they age. To grow they have to shed their exoskeleton, which they do many times during their lives.
Most spiders in this family live for about a year. Females might live longer. Males often die soon after mating.
Breeding season: Spring to Fall, different for different species.
Key Reproductive Features: sexual ; fertilization (Internal ); oviparous
Female sac spiders keep their eggs in the same silken sac that they make to hide in. They guard the eggs until they hatch.
Parental Investment: female parental care
Molecular Biology and Genetics
Statistics of barcoding coverage
|Specimen Records:||1,275||Public Records:||300|
|Specimens with Sequences:||1,229||Public Species:||36|
|Specimens with Barcodes:||1,205||Public BINs:||46|
|Species With Barcodes:||68|
No sac spider species are known to be endangered or in need of protection.
Relevance to Humans and Ecosystems
Economic Importance for Humans: Negative
Though not very dangerous, some species in this family can give a painful bite.
Negative Impacts: injures humans (bites or stings)
Economic Importance for Humans: Positive
Sac spiders are important enemies of many insect pests.
Positive Impacts: controls pest population
|Wikispecies has information related to: Clubionidae|
The sac spiders of the family Clubionidae have a very confusing taxonomic history. Once this family was a large catch-all taxon for a disparate collection of spiders, similar only in that they had eight eyes arranged in two rows, conical anterior spinnerets that touched and were wandering predators that built silken retreats, or sacs, usually on plant terminals, between leaves, under bark or under rocks. These are now recognized to include several families, some of which are more closely related to the three-clawed spiders, like lynx and wolf spiders, than to true "clubionoids."
Among the families formerly classified as sac spiders, some of which have common names including the words "sac spider", include:
- Anyphaenidae (anyphaenid sac spider)
- Tengellidae (tengellid spider)
- Zorocratidae (zorocratid spider)
- Miturgidae (long-legged sac spider)
- Corinnidae (corinnid sac spider)
- Liocranidae (liocranid sac spider)
|This section does not cite any references or sources. (August 2009)|
- Abliguritor Petrunkevitch, 1942 † (fossil)
- Carteroniella Strand, 1907 (South Africa)
- Carteronius Simon, 1897 (Madagascar, Mauritius, Sierra Leone)
- Clubiona Latreille, 1804 (America, Africa, Europe, Asia, Australia, Oceania) (429 recent species)
- Concursator nudipes Petrunkevitch, 1958 †
- Cryptoplanus Petrunkevitch, 1958 † (fossil)
- Cryptoplanus paradoxus Petrunkevitch, 1958 †
- Dorymetaecus Rainbow, 1920 (Lord Howe Island)
- Elaver O. P-Cambridge, 1898 (America, Philippines)
- Eobumbatrix Petrunkevitch, 1922 † (fossil, oligocene)
- Eobumbatrix latebrosa (Scudder, 1890) †
- Eodeter Petrunkevitch, 1958 † (fossil)
- Eodeter magnificus Petrunkevitch, 1958 †
- Eomazax Petrunkevitch, 1958 † (fossil)
- Eomazax pulcher Petrunkevitch, 1958 †
- Eostentatrix Petrunkevitch, 1922 † (fossil, oligocene)
- Eostentatrix eversa Petrunkevitch, 1922 †
- Eoversatrix Petrunkevitch, 1922 † (fossil, oligocene)
- Eoversatrix eversa (Scudder, 1890) †
- Machilla Petrunkevitch, 1958 † (fossil)
- Machilla setosa Petrunkevitch, 1958 †
- Malamatidia Deeleman-Reinhold, 2001 (Malaysia, Indonesia)
- Matidia Thorell, 1878 (South Asia, Oceania)
- Nusatidia Deeleman-Reinhold, 2001 (South Asia)
- Pristidia Deeleman-Reinhold, 2001 (South Asia)
- Pteroneta Deeleman-Reinhold, 2001 (South Asia, Australia)
- Scopalio Deeleman-Reinhold, 2001 (Borneo)
- Simalio Simon, 1897 (India, Sri Lanka, Philippines, Trinidad)
- Tixcocoba Gertsch, 1977 (Mexico)
- Tixcocoda Gertsch, 2011 (Baton Rouge, LA)
- Platnick, N. I. (2010). Clubionidae. The world spider catalog, version 11.0. American Museum of Natural History.
- Tree of Life Web Project. 2006. Clubionidae. Version 25 March 2006 (temporary). http://tolweb.org/Clubionidae/2675/2006.03.25 in The Tree of Life Web Project, http://tolweb.org/