What Are the Adaptations of a Silverfish?

Silverfish like moisture; a good plumber is their worst enemy

A silverfish is not a fish at all, but a remarkable -- some may say disgusting -- insect. The number of insect species exceeds that of all other animal species combined. The variety is simply astounding, but every one of these types of insects has adapted uniquely to its environment. Silverfish display a fascinating array of adaptations that have allowed them to thrive, prosper, and occasionally give humans the willies.

Digesting Cellulose

One of the principal evolutionary adaptations of the silverfish is its ability to digest cellulose. Cellulose is a complex organic molecule, the major component of the cell wall in plant cells, and thus present in almost all plants and many plant-derived products. Very few insects are capable of digesting cellulose. The silverfish is one of the few that can, with assistance from symbiotic microorganisms that live in its digestive system and produce the enzymes necessary to break down the cellulose molecule. This adaptation allows silverfish to exploit food sources unavailable to most other organisms. Most notable among these is wallpaper paste, which silverfish seem to consider an exquisite delicacy. Irregular patches of ruined wallpaper are characteristic of a silverfish infestation.

Survival without Food

While their ability to digest cellulose gives the silverfish a notable advantage, perhaps even more remarkable is its capacity to go for long periods without food. Silverfish have been known to survive for over a year with no food at all. By comparison, the cockroach can only survive from one to three months without food.

Skin Shedding

The silverfish is one of the only types of insects to shed its skin continually through its adult life. This has proven to be evolutionarily adaptive in evading predators. Silverfish have been observed to slip out of their skin to escape from spider's webs. Skin shedding also allows silverfish to grow. Unlike most other insects, silverfish do not undergo metamorphosis, a process in which the insects sequentially go through a larval, pupal and adult stage. A newly hatched silverfish looks like a smaller version of an adult; it sheds its old skin throughout its life as it grows in size.

Living with People

Silverfish thrive in areas of relatively high temperature and moisture. Not surprisingly, they are believed to have originally evolved in tropical regions, and would not likely have successfully colonized the cooler and dryer parts of North America, where they are now commonly found, were it not for another species: Homo sapiens. Homes and other buildings provide the warmth and moisture silverfish need, and they are often found in the warmest and moistest areas of the house. They have adapted well to exploiting the micro-climates created by humans. If you have silverfish in your home and want to get rid of them, the first step is eliminating their water supply. Take care of any leaky pipes and put in a dehumidifier.

References

• Science Daily
• Vancouver Courier; January 16, 2008
• National Pest Management Association Inc
• Texas A&M University
• University of California Statewide Integrated Pest Management Program
• Philosophical Transactions: Biological Sciences Vol. 333, No. 1267, Aug. 29, 1991 The Evolutionary Interaction of Animals and Plants