Why Monitor Spiders?

  Spiders are a fascinating, yet surprisingly misunderstood group of arthropods. They belong to the Phylum Arthropoda, Subphylum Chelicerata, Class Arachnida, and the Order Araneae. They are related to mites and ticks (Order Acari), scorpions (Order Scorpionida), harvestmen or daddy-longlegs (Order Opiliones), among other eight-legged animals (Tree of Life Web Project, 2006). Spiders are not insects because they have two body segments, eight legs, and never possess chewing mouthparts or wings. The study of arachnids is known as arachnology and that of spiders, araneology. All spiders produce silk, although there are many species that hunt freely. Only about 200 of the approximately 40,000 known species (Platnick, 2007) have bites that can pose health problems to humans (Diaz, 2004) and what are commonly thought to be spider bites are usually a result of some other cause (Bennett & Vetter, 2004). When startled, they can move very quickly but their presence in basements and other dark and damp places in human habitations is an indication not of a "spider problem" but of other problems. They're most likely doing you a favor by consuming household pests!

Spiderban & Spider Blaster
Unnecessary & potentially damaging
products best avoided

  Spiders are all predators and sit at the top of their food chains. They are excellent study organisms and are often used in ecological research because they can be easily collected in astounding numbers, making them useful organisms to compare habitats. In particular, spiders show rapid and dramatic numerical responses to changes in the structure of their habitats. They are also one of the first animals to appear after major disturbances such as volcanic eruptions (Crawford et al., 1995) and forest clear-cutting and wildfire (Larrivée et al., 2005). Unfortunately, our knowledge of many species of spiders captured in these ecological works is limited to scientific names and taxonomic drawings. In invertebrate museums, spiders are swamped by the volume of insect specimens, which traditionally receive more attention in biodiversity monitoring programs. However, databases (Shorthouse, 2007; Proszynski, 2007; Wang, 2007) that feature images, geo-referenced collections, and also attempt to assemble what is known about spiders are starting to flourish. There is a common misconception among taxonomists that spiders are difficult to identify. With more and more guides and keys available (e.g. Ubick et al., 2005), this misconception is evaporating and spiders are becoming popular study organisms.

  But, the habits, preferred habitats, seasonal activity, and geographic location of most species, even the visually identifiable species, are still unknown. In fact, we simply haven't a clue if most species in North America are native to this region of the world or what may happen to their distributions in the face of changing global weather patterns. Unlike the attention birds and butterflies receive from well-organized bird and butterfly counts, there has never been an attempt to coordinate citizen science spider observations. That is, until now.


Bennett, Robert G. and Richard S. Vetter. 2004. An approach to spider bites: Erroneous attribution of dermonecrotic lesions to brown recluse or hobo spider bites in Canada. Can. Fam. Physician 50: 1098-1101. PDF reprint

Crawford, R. L., P. M. Sugg, and J. S. Edwards. 1995. Spider arrival and primary establishment on terrain depopulated by volcanic eruption at Mount St. Helens, Washington. American Midland Naturalist 133:60-75. PDF reprint

Diaz, James H. 2004. The global epidemiology, syndromic classification, management, and prevention of spider bites. American Journal of Tropical Medicine and Hygiene 71 (2): 239-250. PDF reprint

Larrivée, Maxim, Lenore Fahrig, and Pierre Drapeau. 2005. Effects of a recent wildfire and clearcuts on ground-dwelling boreal forest spider assemblages. Canadian Journal of Forest Research 35 (11): 2575-2588. PDF reprint

Platnick, N. I. 2007. The world spider catalog, version 7.5. American Museum of Natural History, online at

Proszynski, Jerzy. 2007. Global species database of Salticidae (Araneae). Online at

Shorthouse, David P. 2007. The Nearctic Spider Database. World Wide Web electronic publication.

Tree of Life Web Project. 2006. Araneae. Spiders. Version 07 December 2006 (temporary). in The Tree of Life Web Project,

Ubick, Darrell, Pierre Paquin, Paula E. Cushing, and Vince Roth (eds.). 2005. Spiders of North America: an identification manual. American Arachnological Society. 377 pages. (Available at:

Wang, X. P. 2007. Online Coelotinae, version 2.0. Online at