The largest earthworms in Britain have been discovered on the Isle of Rum by researchers from the University of Central Lancashire. Located just off the coast of Scotland, the Isle of Rum contains conditions that are perfect for giving rise to invertebrate species up to three times the average weight and length. The earthworms, Lumbricus terrestris, weigh up to 12.7 grams and measure approximately 40 cm in length.
Described as an "outdoor laboratory," the Isle of Rum is known for its high quality of nature and is frequently studied due to this fact. The current study took place during the years 2006 and 2011 after the team of researchers discovered unusually large worm burrows. After discovering the giant earthworms, they began to examine the surrounding ecosystem to uncover the factors behind their size.
"I first noticed the large worm burrows in 2005, so I had my suspicions that there may be some pretty big worms in the area," Kevin Butt, who led the study, said in a press release. "We went back out to investigate the following year and finding worms of this size was very exciting, especially when the Natural History Museum team confirmed that they had no specimens like this."
The team found that due to the absence of predators and high fertility of the soil, the worms experienced optimal living conditions and were thus able to grow much larger than the average earthworm, who experiences poorer soil conditions and must face predation. Although the average life span of an earthworm is just a few years, the scientists believe that these large earthworms could live to up to 10 years old.
"There are still unanswered questions and we plan to continue our research to find out as much as possible about these creatures," Butt said. "We're also looking forward to exploring more rural areas in the U.K. and abroad, in the hope that we will make more exciting discoveries of this nature."
The findings were published in The Glasgow Naturalist.
