most wanted: Araneaeology

By |  April 17, 2014

Araneaeology is the study of spiders. As araneaeologists, pest management professionals (PMPs) investigate offenses of our sensibilities. Through their mere presence, spiders can offend customers visually and psychologically.

The commonly encountered American house spider (Parasteatoda tepidariorum) invades numerous construction types. Using silk (spun fiber proteins), the American house spider, which can live longer than a year, constructs asymmetrical webs in corners and angular spaces. Each female averages about seven oval, parchment-like brown egg sacks — about 250 eggs per sack, producing about 3,760 eggs in her lifetime. The sacks can be found in the webbing. Soon after, second-instar spiderlings balloon and produce independent webs.

Adult females are shorter than 1/4 in. long, and males are about 1/6 in. long. With eight eyes and two proximal pairs, the female is yellowish-brown on the carapace (upper exoskeleton) with a dingy-white to brown abdomen. Her legs are yellowish and pale ringed, as opposed to the male’s legs, which are jailhouse orange. Pale chevrons are on the back.

The American house spider produces sticky silk stand webs to capture insect victims. The comb-clawed spider waits within an extra-silky area of the web. Larger victims become entangled, and more aggressively battered, with additional silk and torque. Silks serve various functions:

  • Ampullate (minor) – temporary scaffolding during construction;
  • Ampullate (major) – dragline for the outer rim, spokes and lifeline;
  • Piriform – forms bonds between separate threads (attachment points);
  • Aggregate – glue of sticky globules;
  • Flagelliform – capturing lines;
  • Tubuliform – egg cocoon for protecting eggs; and
  • Aciniform – wraps and secures freshly captured prey and male sperm webs (stabilimenta). pmp
This article is tagged with and posted in Most Wanted, Spiders, Technical

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