Let It Be Dark! Appreciating nighttime foragers

Insects that forage on night-blooming flowers in Maine include sphinx moths. Photo by Wildreturn, Creative Commons 

By Linda Ray

Growing up in our neighborhood, we would venture out into the safety of our backyard on warm, clear summer nights and chase fireflies with a kind of free abandon. Gardens and green spaces at night remain a kind of unknown world for most of us. Nocturnal life carries on in our absence, but, by listening, we may hear screeching, rustling, yipping, and hooting, among other sounds. The night also brings silent insect pollinators that do their work when the evening comes alive.

The group of insects that forage on night-blooming flowers in Maine includes various species of moths, such as sphinx moths, beetles like fireflies, some sweat bees, and thrips. Several nocturnal moths, such as the luna and cecropia moths, are active at night but have no mouthparts. These moths are not after nectar; they are seeking mates and laying eggs.

Insects and plants have co-evolved, producing mutual advantages that make their interactions successful; this is also true for nocturnal insects and plants. Night pollinators are attracted to blooms with clustered, easy landing spots, pale or white blossoms that open in the late afternoon or evening, ample nectar, and strong fragrances. Some plants take advantage of nighttime foragers by producing both diurnal and nocturnal blossoms, allowing them to potentially be pollinated 24 hours a day. This increases seed production, pollen dispersal, and  enhances gene flow and diversity.

Native common primrose, whose shape, color, and aroma attract nocturnal pollinators. Photo by Linda Ray

Plants such as evening primrose (Oenothera biennis), trumpet honeysuckle (Lonicera sempervirens), and moonflowers (Ipomoea alba) grow in Maine and fulfill all of these requirements. Nocturnal moths such as some sphinx moths (Sphingidae) are generalist feeders and visit a wide range of blossoms, including those that daytime pollinators might overlook.

What are the advantages of being a nighttime forager? There are several:

• There is less competition for available nectar. The diurnal crowds thin, and the nocturnal blossoms are available for a smaller population.

• There are fewer predators at night.

• The heat of the summer day is avoided, which decreases water loss for both insects and plants.

• Studies have shown that nocturnal moths can fly longer distances than bees in search of food, thus increasing pollen dispersal range.

Though not as well studied as daytime pollinators, partly because of  the challenges of standard field study methods, the importance of nocturnal pollinators should not be underestimated. They are essential for pollinating many crops and wild plants and are vital for maintaining biodiversity and healthy ecosystems. 

So, the next time you settle into bed after a long day in your garden, know that the all-important work of pollination continues while you sleep. 

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Sources:

• The Night Shift: Moths as Nocturnal Pollinators | Xerces Society

•  Moth Pollination

• Yong, Ed. An Immense World. Random House, NY, 2022

• Lees, David C., and Zilli, Alberto. Moths: A Complete Guide to Biology and Behavior. Smithsonian Books, Washington, DC, 2024