Worms may not have feet to travel with but they do know how to go around courtesy of a form of symbiosis they seem to have formed with fellow invertebrates, a new study says.
Scientists at the Christian-Albrechts-Universität in Germany have discovered how small worms called nematodes, or roundworms, are able to catch a ride within the bodies of larger organisms in search of their next meal. These millimeter-long worms are known to consume rotting fruit and other plant materials.
In a study featured in the open access BMC Ecology journal, zoologist Hinrich Schulenburg and his colleagues at the university collected more than 600 slugs and 400 other species of invertebrates, such as centipedes, locusts, beetles, spiders and flies, from various compost heaps and gardens. They then dissected these specimens and analyzed their anatomy on a microscopic level.
The researchers found that many of the centipedes, woodlice and slugs have the nematode worms living inside their digestive tract. They believe the tiny organisms may have found their way inside after having been swallowed by the larger invertebrates.
Upon further examinations, Schulenburg and his team confirmed that the nematode worms were able to survive and even thrive within the slugs' intestines, and the worms were then excreted alive along with the slugs' feces.
Schulenburg said that while nematode worms are one of the most studied species in almost every known field of biology, little is known about the invertebrates' own natural ecology.
He explained that their study sheds light on the mystery of the worms' lifestyle within the digestive tract of slugs, demonstrating how they were able to evolve in order to withstand the harsh environment of the slugs' intestines.
The findings, however, revealed that the worms could only persist in the intestines of the slugs for less than a day, suggesting that the nematode worms have to invade slugs repeatedly to travel for longer periods.
Other Unusual Symbiotic Relationships in the Animal Kingdom
The peculiar connection between nematode worms and slugs is just another example of a symbiotic relationship that is beneficial to different species of animals.
1. Sloths and Moths
The two-toed sloth's symbiosis with sloth moths centers on the way the animal chooses to defecate. Whenever a sloth needs to poop, it simply releases its waste while staying in its canopy. This is often done to avoid potential predators that could be waiting to snag the animals from below.
The sloth moths living on the animal's back would then fly down and lay their eggs on the sloth's feces. Once these eggs hatch, the moth larvae would use the poop as a source of food, and by the time they have reach maturity, they would fly to where the sloths are and nestle on their fur.
2. Crocodiles and Egyptian Plovers
Another unusual symbiosis is between crocodiles and Egyptian plovers, wherein the tiny birds would often fly down to the mouth of these large reptiles in order to pick the bits of meat that get stuck between their teeth.
The crocodiles appear to understand the benefits of having the plover clean their teeth as they keep their mouth open while the birds do their job. This symbiosis helps prevent the reptiles from contracting infections from the raw meat they feast on.
3. Ratels and Honey Guides
The seemingly mutual agreement between honey guide birds and ratels, or honey badgers, relates to how both animals search for food.
Whenever a honey guide spots a beehive, it would call on ratels on the ground by producing unique chirping sounds and showing off its white-feathered tail. The prospective ratel would then respond by grunting and growling at the bird.
The honey guide would proceed to lead the ratel to where the beehive is located and allow the animal to ransack it for its honey. After the ratel leaves, the honey guide would swoop in and eat the leftover wax.