A woman in Maryland found this worm swimming in her mother-in-law’s toilet and hopes that we can help ID the critter. The worm in questions appears to be a mottled brown color, with a segmented body and a yellow band near its head, as well as a pair of eye spots just below the stripe.
Our reader claims that she cannot find anything similar online and that she is desperate to find out what this worm is and how she can prevent more of them from coming about. Firstly, we want to assure our reader that she needs not be worried about this caterpillar being a health or safety issue to herself, her mother-in-law, or anyone using that bathroom. Secondly, we also want to assure her that, unless some strange phenomenon is occurring, her mother-in-law should not worry about more of these worms crawling up her toilet. Thirdly, we can assure these things because we have identified this critter as an Eastern tiger swallowtail caterpillar.
Eastern tiger swallowtails are a species of butterfly that can be found across a vast portion of North America, from Ontario, Canada, to the Northern parts of Mexico. Their name originates from the pattern on their wings when the male butterflies are fully matured; their wings are yellow/orange in color, with black stripes. The female butterflies have a more varied range of colors they can take on. It was only because of our reader’s excellent pictures that we were able to identify this worm as a caterpillar of this butterfly, which tend to be green or brown in color, with the trademark yellow band by its head, and the two eye spots. However, these eye spots are not actually functional, but serve as a defense mechanism against predators, who will be tricked into thinking the caterpillar is larger than it actually is.
The caterpillars of the Eastern tiger swallowtails feed on the leaves of various plants and trees, while the butterflies feed on the nectar of flowers. In addition to this, Eastern tiger swallowtails tend to travel alone, because the female butterfly only lays one egg at a time. It is for these reasons that infestations of Eastern tiger swallowtails are very unlikely. Thereupon, we would conclude that the discovery of this caterpillar in our reader’s mother-in-law’s toilet was purely an accident on part of the caterpillar. It is possible it either wandered in through a hole in a window screen, or through an open door, and found its way into the toilet. This would make sense, given that the natural habitat of these creatures are in forests, specifically near bodies of water such as streams, swamps and rivers. Thus, the caterpillar was most likely attracted to the toilet water, as it reminded it of the environment in which it normally thrives.
Lastly, it is important to point out that these creatures, like all pollinating butterflies, are vital to our environment, so we advise not to kill them under any circumstance. In fact, many gardeners will purposefully try to attract them to their gardens to pollinate their gardens, or for aesthetic reasons. Although finding any worm in one’s toilet may not be a lovely experience in and of itself, these critters are normally welcome guests to one’s garden. We recommend that our reader places the caterpillar outside, near a tree if she can, so that the caterpillar can feed and maturate properly. In order to prevent more worms and caterpillars from wandering into her home, it might be worth checking any points of possible entry for small critters, such as holes in window screens, and gaps/cracks in the walls and floors, and sealing them.
To conclude, the creature our reader found in her mother-in-law’s toilet was an Eastern tiger swallowtail caterpillar! These harmless larvae belong in the outdoors, where they can eventually pollinate the flowers and help the environment, and should not be feared as they are completely harmless to humans.