The segmented worm is a common sight, whether it is on a wet pavement, in a compost bin, or on the end of a fishhook. But what about all the other worms out there?
The phylum Nemertea, which contains more than 1,000 species of tapeworms, is diverse in terms of size and way of life. The majority of these species are found in the ocean. The proboscis, a peculiar muscle structure in the worm’s body, is one of tapeworms’ distinguishing characteristics. They exert pressure on their bodies to force their proboscis out of their bodies in order to attack prey.
Proboscis of a ribbon worm
The laceworm Lineus longissimus, which squirms between rocks in North Sea waters, is the largest species of tapeworm. It’s not just the biggest nematode; it might also be the longest! Confusion persists since it is challenging to measure these stretchy worms precisely, but they are longer than 30 meters (98 feet) and may even reach 60 meters (197 feet), which is longer than a blue whale! They are less than an inch tall despite being quite long.
The shortest species of tapeworm, less than an inch long, resembles a thread more than a worm, contrary to popular belief.
When threatened, tapeworms may shrink to one-tenth of their extended length thanks to highly developed muscles in their bodies. Speaking of stretching, certain species of tapeworm may consume prey that is twice as wide as themselves, including different kinds of worms, fish, crabs, snails, and mussels.
The proboscis differs between species. Some species, like those of Hoplonemertea, even stick prey on their proboscis with sharp spines called stylets. Others are sticky or have suckers to grab prey.
Worms continually create and use replacement stilettos that they store in their inner pouch because they are frequently lost during raids.
Many tapeworms are toxic and have a foul taste, which acts as a secondary defense. Tetrodotoxin, the infamous poison known to cause paralysis and death by suffocation, is present in several species of puffer fish. Although it is unknown how the toxins are made, they may be left behind in the worm by bacteria that have been ingested. These toxins may serve as a deterrent to predators. Even some of them expel poison from their proboscises.
