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Sewer Lice

Background

Lice (singular: louse) is the common name for over 3000 species of wingless insects of the order Phthiraptera; three of which are classified as human disease agents. [1] Most lice are scavengers, feeding on skin and other debris found on a host's body, but some species feed on sebaceous secretions and blood. A louse's color varies from pale beige to dark gray; however, if feeding on blood, it may become considerably darker.[2]

Novel Species
A little more than a decade ago, some workers involved in a sewer reconstruction project in Maryland discovered a previously unknown insect. Scientists have since identified the creatures as Pediculus humanus vastus (Sewer Lice), a mutated form of the more common human parasite. [3] They are as much as 100 times larger than the average louse. Young sewer lice appear identical to adults, only smaller. Strikingly, sewer lice are no longer parasitic—they have adapted to life away from a host by feeding on human waste found in sewage water. These insects are now considered to be an integral part of biological wastewater treatment.[4]

Behavior
Sewer lice spend the majority of their time feeding near the bottom of the sewer, where debris collects, or swimming to the surface to obtain oxygen. As they spend nearly all their time in an aqueous environment, their preferred method of locomotion is swimming, rather than walking. They expel carbon dioxide gas as a byproduct of their metabolism.

Sewer lice demonstrate a sensitivity to bright light and appear more active in dark environments. As they are ectothermic, they also prefer to be kept at slightly cool to room temperatures. However, they are otherwise quite hardy creatures and non-pathogenic, which makes them an excellent live specimen for middle school and high school science classrooms. [5][6][7]

Habitat
Sewer lice can be found throughout North America. They are not endangered so it is possible to collect large quantities of specimens directly.

[1] [2] [3] [4] [5] [6] [7]

References

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  1. ^ a b http://extension.usu.edu/files/publications/factsheet/human-lice'08.pdf
  2. ^ a b http://tolweb.org/Phthiraptera
  3. ^ a b Copyright 2010, Flinn Scientific BioFax, http://www.flinnsci.com/Documents/demoPDFs/Biology/BF10054.pdf
  4. ^ a b Henze, M. et al. (2008). "Biological Wastewater Treatment: Principles, Modelling and Design", London: Cambridge University Press.
  5. ^ a b Hassard, J. (2000). "Science As Inquiry", Parsippany: Good Year Books.
  6. ^ a b Jorgeson, O. et al. (2004). "Doing good science in Middle School: A Practical Guide to Inquiry Based Instruction", NSTA Press.
  7. ^ a b http://go.hrw.com/resources/go_sc/gen/HSTPR060.PDF
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