earthworm
蚯 refers specifically to an earthworm, a creature associated with soil and burrowing.
蚯 is a phono-semantic compound: the insect radical 虫 indicates a creature, and 丘 (キュウ) provides the sound. Together they represent the earthworm.
An insect 虫 that lives in mounds 丘 of soil: that's an earthworm.
For キュウ, imagine a cute earthworm named 'Q' (kyuu) wriggling in the dirt: Q -> キュウ.
Iberian worm lizard (Blanus cinereus); European worm lizard
Marphysa sanguinea (species of eunicid worm)
Epimenia verrucosa (mollusc)
eunicid (any worm of family Eunicidae)
earthworm
worm lizard; amphisbaenian
flat-headed goby (Luciogobius guttatus)
cry of earthworms (heard on autumn nights and rainy days)