There are over 1,300 species of mistletoe throughout the world; the species most commonly associated with our Yuletide custom in the US is the native American or Oak mistletoe (Phoradendron leucarpum).
All mistletoe species are parasitic, eventually causing the death of their host. The sticky seeds typically reach their host thanks to a bird that has eaten a berry, which deposits the seed onto the tree or shrub (0ften with fertilizer included!). Though mistletoe might seem like an undesirable plant because it kills its host trees, some are important keystone species in their habitats.
Three species of hairstreak butterflies (great purple hairstreak, thicket hairstreak, and Johnson’s hairstreak) in the United States depend on mistletoe as a host plant. Females lay their eggs on the leaves; when the caterpillars hatch, they feed on the leaves. The adult butterflies feed on mistletoe nectar, as do honeybees and other native bees; indeed, mistletoe flowers provide one of the earliest available nectar sources for bees.
In addition to butterflies, birds and bees, deer, elk, squirrels and porcupines seek mistletoe berries during the late fall when other food sources become scarce. Mistletoe also provides important winter cover and nesting sites for many birds.
Author: Lisa Schneider
Photo Credit Anthony Valois, and the National Park Service, found at smmflowers.org.