Symbolism, Imagery, Allegory
The only real mother we meet in this novel is Mrs. Westenra, Lucy's mother, and she dies pretty quickly. Mina takes over as everyone's mother, and boy is she good at it: Not five minutes after she meets Arthur Holmwood, she has him crying on her shoulder like a baby:
We women have something of the mother in us that makes us rise above smaller matters when the mother-spirit is invoked; I felt this big, sorrowing man's head resting on me, as though it were that of the baby that some day may lie on my bosom, and I stroked his hair as though he were my own child. (17.58-59)
Motherhood sounds almost holy here: It's an instinct, or a "spirit" that can be "invoked" and that helps women "rise above" everyday stuff. Contrast the passage about Mina, above, with this description of vampire-Lucy:
With a careless motion, she flung to the ground, callous as a devil, the child that up to now she had clutched strenuously to her breast, growling over it as a dog growls over a bone. The child gave a sharp cry, and lay there moaning. (16.19)
If vampirism and blood-sucking can be read as a twisted version of Holy Communion, female vampires can be read as twisted, diabolical, mean mamas. Instead of saint-like mothers, they get all voluptuous and scarily sexy. Instead of nurturing children against their breasts, they feed on children and chuck them onto the ground.