Californians are observing uncommonly large swarms of dragonflies across the state, a phenomenon experts suggest is linked to unusually warm spring rains. The dragonflies have been seen in parks, near ponds, and in agricultural areas.
Peter Veilleux, a nursery owner in Oakland, reported seeing groups of about 100 dragonflies flying together in local parks and around Lake Merritt in July. His social media posts about the sightings prompted numerous comments from other Californians who had observed similar swarms in the San Francisco Bay Area and beyond.
While dragonflies typically emerge in the summer months, Kathy Biggs, a dragonfly expert and co-author of “Dragonflies of California,” noted that this year's substantial numbers are likely a result of warm monsoon storms that occurred in late spring and early summer. She identified many of the insects as wandering gliders, a migratory species known to appear in large numbers when environmental conditions are favorable. These dragonflies can reach speeds of up to 35 mph and utilize air pressure changes for long-distance travel.
In Fresno County, farmer Joe Del Bosque observed swarms flying at heights of 10 to 20 feet. While dragonflies are a regular presence on his farm, he noted their numbers were higher than usual this year. Del Bosque welcomed the insects, as they act as natural pest control by consuming aphids, whiteflies, and fruit flies that threaten his crops.
Dragonflies undergo a significant life cycle, beginning as eggs laid in freshwater. The immature stage, known as nymphs, live underwater for at least six months and up to five years, feeding on mosquito larvae, tadpoles, and other nymphs. Upon emerging from the water, they transform into winged insects capable of complex aerial maneuvers, including hovering and flying backward.
Their adult lifespan is relatively short, lasting only a few weeks or months. During this period, they focus on hunting smaller insects and reproducing. Chris Grinter, senior collection manager of entomology at the California Academy of Science in San Francisco, described dragonflies as highly agile and powerful predators with excellent vision, capable of consuming hundreds of mosquitoes daily. He noted that over 90% of their hunts are successful.
Historically, dragonflies have held symbolic meanings across various cultures. In Native American traditions, they represent purity and happiness, while in Japan, they symbolize power and victory. Conversely, some European folklore has associated them with evil or bad luck.
To encourage dragonflies in garden settings, Biggs suggests avoiding pesticides and creating habitats such as fishless ponds and sunny areas with perches. California is home to approximately 70 dragonfly species, though most are not migratory and remain in their emergence locations. Some species are active as early as spring, even during snowmelt, while others inhabit arid regions like the Mojave Desert. The migratory species, as Biggs explained, travel by