They play an important role by transferring pollen between flowers and allowing plants to successfully produce seeds. These hard-working animals help pollinate more than 75 percent of flowering plants, and nearly 75 percent of our crops. An estimated 75 to 95 percent of all flowering plants in the world cannot self-pollinate (they need a pollinator’s help) so these species play an important role – not only do they help keep desert ecosystems healthy, they help pollinate the food humans depend upon. Hummingbirds (family Trochilidae): When visiting the refuge, you might be startled by a loud humming noise. The culprit is most likely the hummingbird, a small and colorful pollinator with a long, tapered bill and bristled tongue. The noise results from the flapping of its wings which beat up to 80 times per second. This adaptation, as well as the hummingbird’s ability to fly in any direction (including upside down and backward), makes it an excellent pollinator as it can hover in front of flowers when feeding. The hummingbird is generally attracted to long, tubular, and brightly colored flowers, though it will visit nearly any nectar-producing flower. When the hummingbird feeds on a flower's nectar, sticky pollen attaches to the bird’s bill or feathers. As the hummingbird flies from flower to flower, it spreads the pollen and fertilizes the plant. There are five species of hummingbirds found on Kofa National Wildlife Refuge, including Costa’s hummingbird, black-chinned hummingbird, Anna’s hummingbird, broad-tailed hummingbird, and rufous hummingbird.
White-winged dove (Zenaida asiatica): Named for the white stripe at the edge of its wing, the white-winged dove is another common bird pollinator on the refuge and is considered a saguaro specialist. It is almost exclusively dependent on saguaros for nutrients and water during the breeding season, eating pollen, fruits, nectar, and seeds of saguaros. While feeding on saguaro pollen, the white-winged dove inadvertently pollinates the cactus. It also helps disperse seeds contained within the saguaro fruit it eats, either through its feces or regurgitation to its young. The white-winged dove is so reliant on saguaros that its migration and breeding season matches the flowering of the saguaro, and the species’s distribution overlaps saguaro distribution in the Sonoran Desert.Tarantula Hawk (family Pompilidae): One of the most interesting insect pollinators on Kofa National Wildlife Refuge is the tarantula hawk, a large blue-black wasp with bright orange wings. While the tarantula hawk pollinates plants as it feeds on nectar from flowers, it is primarily known for its unique relationship to tarantulas. When a female tarantula hawk is ready to reproduce, she searches for a tarantula burrow. By touching and strumming the silk at the entrance, she entices the tarantula to leave the safety of its burrow. A battle then ensues, most often ending with the tarantula receiving a paralyzing sting to its underside. The tarantula hawk drags the tarantula into a pre-dug burrow, lays her eggs on the still living spider, and leaves. When the tarantula hawk eggs hatch, the larvae turn the tarantula into their first meal.
Cactus Bees (Diadasia spp.): The most diverse pollinators on earth, bees in the southwest region reach up to 1,000 different kinds of species. On Kofa National Wildlife Refuge, cactus bees are incredibly important as they favor the flowers of cacti. They are fuzzy-brown and about the size of a honey bee. The solitary ground nester is active primarily between April and June when many of the cacti are blooming on the refuge. The cactus bee crawls inside the flowers of saguaros, prickly pears, barrel cacti, teddybear chollas, and other cacti to feed on their nectar, gathering pollen on its hairy body all the while. As the bee flies flower to flower, the pollen is spread and the plant becomes fertilized.
To learn more about pollinators and how you can help encourage pollinator abundance and diversity, visit www.fws.gov/pollinators or www.pollinator.org.
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