Unseen but on the job: The Vibrant Working World of Nocturnal Pollinators
Tamra Boyce, Anoka County Master Gardener Volunteer
After the sun sets, the moon awakens revealing shadows gliding and swooping, seeking and hovering, drawn to gleaming leaves and luminous flowers. These unique plants invite nocturnal insects and animals to collect and harvest their pollen and nectar.
Plants and flowers attractive to nocturnal pollinators already grow in local prairie meadows and woodlands. During an evening stroll you can see Silvery Sedge (Carex argyrantha) or Night-Flowering Catchfly (Silene noctiflora) reflecting the moonlight. Incorporate night-blooming plants into existing gardens spaces or showcase them in a moon garden. Moon gardens feature plants that shine after the sun sets. Examples include Dusty Miller (Jacobaea maritima), which has a silvery look, and Night-Blooming Jasmine (Cestrum nocturnum), which has a powerful scent.
Coexisting with nocturnal plants are nocturnal insect pollinators, such as beetles, which have provided pollination services since the Cretaceous period, long before bees and butterflies. The night foraging Click (Elaterids), and Darkling (Tenebrionids) beetles are accidental pollinators. As these insects search among plants for edible flower parts, they collect pollen unintentionally, transferring it from blossom to blossom as they travel across flowers.
Fireflies or Lightening Bugs (Lampyridae) are also beetles active in low-light environments. How fireflies pollinate is not well understood; it is believed they pick up pollen on their bodies then transfer it to flowers they visit. Mice, voles, and other small animals also provide accidental pollination services as they move through and between plants.
Moths are responsible for a large percentage of pollination services, deserving a share of the pollination limelight dominated by bees. There are more than 11,000 moth species in the U.S., and Minnesota hosts at least 800 species. Moths collect nectar like bees, but unlike bees, they do not store nectar in their bodies or transport it to a hive. Moths visit more flowers on a single night than do bees, even visiting flowers that bees avoid. As Moths consume nectar, their bodies collect pollen dust that is transferred to flowers during their wide-ranging feeding route.
One notable moth species is the Five-Spotted Hawk Moth (Manduca quinquemaculata). Like hummingbirds, these Hawk Moths hover motionless in mid-air to extract nectar from flowers with their long proboscis. They depend on scent cues and flower brightness to locate blooms such as the spectacular Moonflower Vine (Ipomoea alba) enticing the hawk moth to its delicate bell-shaped white flowers glowing under the moonlight. Ironically, while the five-spotted Hawk Moth is an important pollinator, its larva is a familiar garden pest: the tomato hornworm caterpillar is a ravenous consumer of tomatoes and peppers.
Moth populations are declining due to pesticide use and light pollution. Artificial lights interfere with their navigation and ability to find mates and food. Applying pesticides during evening hours to protect bees can harm nocturnal pollinators so use integrated pest management techniques whenever possible.
Consider adding native night-blooming plants to your next garden upgrade. Including white Alyssum or a few Night Phlox flowers helps support nocturnal pollinator populations.