The dense webs form a sheet that narrows to a tube or funnel where the spider hides awaiting prey on its web. Grass spider webs are ubiquitous on evergreen shrubs and tall grass. Neriene digna (photo of courting pair, male on left) is particularly common in the Bay Area in the spring. Linyphiid webs are usually flat sheets under which the spider hangs upside-down. There are lots of linyphiids, and the taxonomy is a real mess. Neriene digna (Linyphiidae) – “money spider” Zygiella x-notata (Araneidae) – “missing sector orb weaver”Īnother common invasive, this spider makes a vertical orb web with two sectors missing, looking like a pizza with a single slice missing. (Araneidae) – “silver garden spider”, “yellow garden spider”, “banded garden spider”Ĭommon in gardens, makes an orb web with conspicuous, shiny, radiating “stabilimenta”. This orbweaver decorates its vertical orb web with a line of debris, in which are hidden the spider and egg sacs. Ĭyclosa conica (Araneidae) – “trashline orbweaver” Īraneus diadematus (Araneidae) – “cross orbweaver”, “European garden spider”Īnother European invasive, this spider can become quite imposing in size and density in the late fall. Parasteatoda tepediorum (Theridiidae) – “American house spider”Ī common invasive, believed to be from South America. Left: Steatoda grossa, Right: Steatoda nobilis. These spiders are roughly the same size and shape as a black widow, but are brown with a faint purple sheen. Two other European invasives, these spider seems to be displacing our native black widows in urban areas. Steatoda grossa & Steatoda nobilis (Theridiidae) – “false widow” Males and immature females are not solid black, and have attractive marble-like patterns on their abdomens. The red hourglass may be yellow or orange, and may not actually be shaped like an hourglass. This is the only spider that you are likely to encounter in California whose venom is medically significant. Latrodectus herperus (Theridiidae) – “black widow” When disturbed the spiders often gyrate in their webs. Pholcus can be distinguished from Holocnemus (“marbled cell spider) by the grey/brown concolorous abdomen. Sometimes confused with “daddy long-legs”, which are not spiders, but rather Opiliones (“harvestment”). The common synanthropic cellar spiders in California are European invasives, native pholcids are much smaller. Pholcus phalangioides & Holocnemus pluchei (Pholcidae) – “cellar spider” ĭysdera crocata (Dysderidae) – “Sow-bug killer”Ī mediterranean invasive, this spider is usually found under wood or bark. As with tarantulas, the spiders are usually safely hidden in their burrows, and wandering males are the most likely to be encountered. The similar Calisoga thevenetti is less frequently seen. There is considerable variation in color and form. Very frequently encountered in the Oakland hills. “I can’t believe it’s not a tarantula!” Often mistaken for a tarantula, Calisoga is smaller and unable to climb smooth surfaces. Ĭalisoga longitarsus ( Nemesiidae) – “Calisoga spider,” “False tarantula.” Males are often seen wandering in search of females in the fall. The females live in burrows and are occasionally dug up in gardens. (Theraphosidae) – “Tarantula”Īll of California’s native tarantulas are in the genus Aphonopelma. How to identify and misidentify a brown recluse spiderĪphonopelma spp. Spiders also are accused of biting people (or worse), but very rarely has this ever been witnessed. Note that to the untrained eye many spiders look similar – having a spider in hand will be much easier to identify than a fuzzy cell phone photo and trying to remember what it looked like running away. A collection of commonly encountered spiders in the Bay Area, assembled by Dr.
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