Are Black Worms Sensitive to Light?

The blackworm ̵1; also known as the California blackworm or mudworm ̵1; thrives within shallow waters edging ponds or rivers. They are native to the United States and breed in habitats worldwide. Their genus of Annelida and class of Oligochaeta make the blackworm a relative to the common earthworm. And, like worms worldwide, the blackworm is highly sensitive to light, particularly direct sunlight.

  1. Natural Habitat

    • The blackworm seeks only oxygen, moisture and a food source in its environment. Like most worms, it lives in darkness; the blackworm lacks true eyes but senses light via photoreceptor cells in its tail. Typical of most worm species, the segmented, bristled blackworm also has no skeleton, breathing through its skin and moving via muscles attached to a body-length nerve cord that propel it through water or on moist land.

    Home Cultivation

    • People typically buy blackworms at pet stores to use as fish food. Cultivating the creatures at home involves keeping a closed container filled with water and rinsing the worms regularly. The container̵7;s top both shields the worms from light and prevents them from escaping. AquariumFish.net gives an example of a container stored underneath a bench on the southwest side of a house, where direct sunlight will not reach the sensitive worms.

    Effects of Light and Heat

    • The most immediate effect of light and heat on a blackworm is to dry out the exoskeleton. Anne P. Mitchell of All About Worms notes that a worm can become paralyzed within an hour̵7;s exposure to the sun. ̶0;Simply put,̶1; says Mitchell, ̶0;the sun dries out the skin, resulting in paralyzation and suffocation.̶1; The signs of a dehydrating blackworm include the creature appearing to struggle towards a dark enclave. The worm may also feel dry to the touch.

    Other Considerations

    • AquariumFish.net notes that blackworms are also highly sensitive to chlorine and chloramine. The site advises worm cultivators not to use tap water to rinse the worms, but to pour pond water on them instead. The species is also a target for parasites. Frank Indiviglio, writing in NetPlaces, advises: ̶0;Next time you purchase black worms as food for your fish, look closely for a small type of leech that usually lives with them ̵1; their ability to quickly suck down black worms is quite interesting.̶1;