Observations by yhameenhamid

Spiders are one of the most diverse set of organisms on the planet, with approximately 42,000 known species as well as a predicted 100,000 unknown number of species yet to be discovered (Barrett & Hebert, 2005). The species of spider in which Canadians will interact the most with during their lifespan is the American House Spider or more commonly known as the Common House Spider. Cobweb Spider, Comb-footed Spider and simply House Spider are all other common names the species is known as(Bucle, Dondale, Dupérré & Paquin, 2010). The common name(s) of the species are used around the world for a wide variety of spider species, depending on geographical location and as such is highly discouraged to be used as a method of identification (Bucle et al., 2010). The scientific name for the species is Parasteatoda tepidariorum and this is the name preferably used for identification (Barrett & Hebert, 2005).
Parasteatoda tepidariorum has a rather large geographical range that covers most of North America. The species is found in all 50 US States as well all 10 Canadian Provinces (Damen, Hilbrant & McGregor, 2012). Researchers believed the common ancestors of all house spiders originated in Germany but genetic analysis would suggest the most recent starting point of the species was actually in South America (Damen, 2012). Common House Spiders are found commonly in homes as the name would suggest but they actually prefer to be outside but are still very closely associated with human built structures such as buildings, houses and bridges. Parasteatoda tepidariorum have no issues living or surviving indoors as they are commonly and often found in garages, basements, sheds and houses (Damen, Hilbrant & McGregor, 2012). Such spiders can also be found away from human made structures if similar environmental conditions are obtained such as in tree holes, on woodpiles or on natural rock walls (Damen, Hilbrant & McGregor, 2012). Common House Spiders who live outdoors are easily able to migrate indoors and adopt with very little issues however such spiders that are forced to go outside will have decreased fitness and rarely survive beyond a few days (Tanaka & Takasuka, 2013). Female spiders will always be found on their webs whereas males who travel a lot can be found all over the place (Bucle et al., 2010).
Parasteatoda tepidariorum vary greatly in appearance between the two sexes. The female is much larger, which has a body length of 5-9 mm whereas the males range from 4-5 mm (body length excludes leg length) (Eberhard, 1988). The weight of such spiders varies greatly between the sexes and varies throughout the year. However, males tend to weigh around 0.1 g whereas females can be in the range of 0.8 g – 1.0 g but spiders as well as most bugs and insects will only have their size measured to avoid inaccuracy (Eberhard, 1988). The life expectancy of house spiders is very interesting. Females on average live for 1 year after reaching maturity but can live for several years if they can avoid harsh winters (Tanaka & Takasuka, 2013). Most females will die after all her eggs hatch and the produced juveniles disperse from the home web. The process of mating and taking care of the upwards of 15 egg sacs (hundreds of eggs) takes a lot out of the female (Mittmann & Wolff, 2012). A single harsh cold day kills virtually all common house spiders expect those living in warmed housing (Damen, 2012). Such spiders can live upwards of 2-3 years if they survive each mating process (Tanaka & Takasuka, 2013). Males on the other hand only live a few months at best and die shortly after mating (Tanaka & Takasuka, 2013). Males have a significantly shorter time span for a variety of reasons. They move a lot more than females (in search of mate) and as such are exposed to more predation or accidental death (stepped on) (Tanaka & Takasuka, 2013). Males also eat very little once they mature as all time and resources are spent looking for a mate and once a mate is found any remaining energy/resources are used in the process (Bucle et al., 2010). If a male survive through the mating process the female well consume the male as he is vulnerable, useless in helping in egg sac care and due to large size difference and close proximity little energy is required by the female to eat him (Bucle et al., 2010) .
The diet of Parasteatoda tepidariorum mainly includes pests found inside or near houses, buildings, etc. Such pests include flies, ants, wasps and mosquitos make up the large portion of their diets (Barrett & Hebert, 2005). However, such spiders can consume larger prey such as butterflies, grasshoppers, cockroaches and even other spiders (same species or not) (Barrett & Hebert, 2005). The females usually just eat whatever gets caught in her web but when food becomes scarce will attack distant prey by shooting webs at it (Eberhard, 1988). Males tend to consume very little food during maturity and will leech off the female’s resources during mating until his death (Eberhard, 1988). Females will also consume her mate as well as a few of her offspring in order to stay alive and insure a large portion of her eggs can hatch (Mittmann & Wolff, 2012). In order for the young to grow the female will intentionally leave some of her eggs infertile so the fertile offspring that hatch can use those infertile eggs as a source of early food (Mittmann & Wolff, 2012).
Females almost never leave their initial webs and it is the more motor males that look around for females (Mittmann & Wolff, 2012). The males identify themselves to the females by species-specific dancing and rhythmic vibrations (Mittmann & Wolff, 2012). Although such vibrations and dances are used as identification, researchers have observed that spiders will ignore each other if they are unable to see each other (unable to see how healthy they are) (Mittmann & Wolff, 2012). Females also prefer smaller males as they are easier to mate with as well as easier to consume post mating which increases her fitness and her offspring’s fitness (Mittmann & Wolff, 2012). The male then inserts his pedipalp (which has his sperm on it after placing a sample on the tip) into the female’s epigynum (Mittmann & Wolff, 2012) . The two fit perfectly like a lock and key and this mechanism prevents cross-breeding between species (Mittmann & Wolff, 2012). Upon completion the male may leave a portion of his pedipalp inside the woman to prevent further mating from other males (Mittmann & Wolff, 2012). Females can mate with numerous males as well as the same one multiple times (Mittmann & Wolff, 2012). The female then is able to choose which sperm to use and has its own mechanism to choose the better sperm from the better male (Mittmann & Wolff, 2012). The female is then able to fertilize which eggs she wants and usually consumes the male as a food source. Males can court premature females and then waits along their sides until ready in which the female will signal to the male she is matured through vibrations (Mittmann & Wolff, 2012). Males will also spend time afterwards with the female until he is eventually eaten or dies (Mittmann & Wolff, 2012). Spider’s main method of communication is seismic communication with other spiders (Mittmann & Wolff, 2012). Different species go about it differently but house spiders project the vibrations only from the rubbing of their legs (Mittmann & Wolff, 2012).
Parasteatoda tepidariorum have very few predators as most would get caught in its trap or are unable to locate them as they live in dark or covered locations (Bucle et al., 2010). Spiders of the genus Mimetus as well as 2 species of jumping spiders, named Phidippus variegatus and Metacyrba undata also prey on house spiders but may become the prey if get caught in their webs. Stenolemus lanipes known as the assassin bug feed only on spider-lings but themselves are pray to female house spiders (Bucle et al., 2010). Parasteatoda tepidariorum are very aggressive towards any other species in order to protect their webs outsides of humans which they will allow to get very close to their webs, a behaviour heavily being studied today (Bucle et al., 2010). If the spiders are fearful they will hide, play dead or in extreme cases bite with moderate toxicity (Damen et al., 2012). The bite resembles a bee sting; cause pain and inflammation but no medical attention is required. This bite is poisonous to some predator species outside of the home such as some breeds of lizards (Damen et al., 2012).
No conservation action has been conducted nor has the common house spider been targeted for any conservation action (Damen et al., 2012). Common House Spiders are considered as “Low Risk” and fall under the category of ‘Least Concerned’ which is the lowest possible level when enough information is provided (Damen et al., 2012). Having very little predators, a variety of food sources as well as having high reproduction rates (lots of offspring per mate) there is little reason to believe the population will be at risk any time soon.
Did You Know that the most common location to find spiders outside of the basement is the bathroom and no they did not come through the pipes as most would falsely believe. They just wanted some water and enter drains only to find out it isn’t very easy to get back out (Brown, 1981).

References
Barrett, R.D.H. & P.D.N. Hebert, (2005). Identifying spiders through DNA barcodes.
Canadian Journal of Zoology, 83: 481-491. doi: 10.1139/Z05-024
Brown, K.M. (1981). Foraging ecology and niche partitioning in orb-weaving spiders. Oecologia, 50: 380-285. doi:10.1007/BF00344980
Bucle, N., Dondale, C. D., Dupérré D. J. Paquin, P. (2010). Checklist of the spiders (Araneae) of Canada and Alaska. . Zootaxa, 2461: 1–170. Retrieved from http://www.agr.gc.ca/eng/abstract/?id=20295000020295
Damen, G. M., Hilbrant, M. & McGregor P. A. (2012). Evolutionary crossroads in developmental biology: the spider Parasteatoda tepidariorum. Development,139:2655-2662.
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Eberhard, W. (1988). Behavioral Flexibility in Orb Web Construction: Effects of Supplies in Different Silk Glands and Spider Size and Weight. The Journal of Arachnology, 16(3), 295-302. Retrieved from http://www.jstor.org/stable/3705916
Mittmann, B. & Wolff, C. (2012). Embryonic development and staging of the cobweb spider Parasteatoda tepidariorum C. L. Koch, 1841. Development Genes and Evolution, 222(4):189-216. doi:10.1007/s00427-012-0401-0
Tanaka, K. & Takasuka, K. (2013). Seasonal Life Cycle of Zatypota albicoxa (Hymenoptera: Ichneumonidae), an Ectoparasitoid of Parasteatoda tepidariorum (Araneae: Theridiidae), in Southwestern Japan. Pacific Science, 67(1):105-111. doi: http://dx.doi.org/10.2984/67.1.7