Environment & Climate
Unusual dragonfly swarms sweep across California after warm spring rains
Experts attribute the rise of the migratory insects to monsoonal weather, providing natural pest control for local farms and parks.
The short version
- Californians in the San Francisco Bay Area and Fresno County have reported unusually large groups of dragonflies starting in July.
- Experts believe the spike in population is due to warm late-spring and early-summer monsoon storms creating ideal conditions for migratory wandering gliders.
- The surge is benefiting local agriculture, as dragonflies are highly effective predators that consume major crop pests and mosquitoes.
Key facts
- Residents and farmers in regions such as the San Francisco Bay Area and Fresno County reported spotting unusually large numbers of dragonflies starting in July.[ABC News]
- Dragonfly expert Kathy Biggs attributes the swarms to warm monsoon storms in late spring and early summer, identifying the insects as likely being wandering gliders.[ABC News]
- Wandering gliders are a highly migratory species that travel long distances by utilizing changes in atmospheric pressure.[ABC News]
- California is home to about 70 dragonfly species, though most are non-migratory and remain near their local freshwater emergence points.[ABC News]
- According to entomologist Chris Grinter, dragonflies are exceptionally successful predators with a hunt success rate exceeding 90%, allowing them to consume hundreds of mosquitoes daily.[ABC News]
- Farmers have welcomed the swarms because the insects naturally suppress agricultural pests such as aphids, whiteflies, and fruit flies.[ABC News]
Sources
- Unusual dragonfly swarms sweep across California after warm spring rainsABC News - US News