Recent research has the oldest common ancestor of mites (arachnids) and insects as emerging on earth around 570 million years ago. The earliest insect and arachnid species that existed on earth are long gone, but numerous common and similar looking insect and arachnid species continue to inhabit the planet to this day. Fossil evidence suggests that arachnids emerged before insects, as the modern huntsman spider is believed to have emerged around 570 million years ago, and researchers believe that the first true insects emerged around 479 million years ago. Fossil evidence indicates that arachnids and insects evolved from sea-dwelling creatures, which should not be surprising considering the clear resemblance between crustaceans, like crabs and lobsters, and large arachnids, like huntsman spiders and scorpions. While cockroaches are often cited as being the oldest living group of insects, there is actually at least one modern insect species that emerged at least 200 million years earlier than roaches, and given this insect’s appearance, nobody would doubt its aquatic origin. This species, Lepisma saccharina, is a common house pest all over the world today, and most people know this species as the “silverfish.”

The ancestry of silverfish dates back 420 million years, and the modern silverfish we recognize today as unwanted house pests emerged around 270 million years ago. Cockroach ancestors date back 430 million years, and the first cockroach fossil ever found dates back 170 million years, but this fossilized species is now an extinct ancestor of the roaches that exist today. The silverfish, as its common name suggests, closely resembles a fish, as they possess a fairly flat and grey-colored scaly outer shield that obscures their six legs. Not only does this species look like a fish, but it even moves like one at extremely fast speeds, making them difficult to catch. Moist and dark indoor environments are ideal for silverfish, and they have no problem accessing homes through tiny cracks in a foundation, window screen or utility openings. Once indoors, female silverfish proceed to lay around 200 eggs per day while inhabiting areas like basements, cellars, bathrooms, kitchens or even behind furniture. As you can imagine, their rapid reproduction rate and fast speed allows these insects to establish indoor infestations rapidly. Pest control professionals are often called upon to remove silverfish from homes, and professional help is certainly necessary in these cases due to the insect’s nuisance presence, as well as their insatiable appetite for paper, books, soaps, garments, mold, dandruff, hair, glue, skin, beef pork, cereal, flour and cardboard boxes. Silverfish measure around three fourths of an inch in length and they commonly infest all types of indoor environments no matter the relative cleanliness of the conditions.

Have you ever spotted a silverfish in your home?