Twelve-spotted Skimmer

The Twelve-spotted Skimmer is one of the largest and most recognizable skimmers in North America, named for the twelve dark spots spread across its four wings (three per wing). It belongs to the family Libellulidae, the perchers and skimmers, whose members typically hunt from a favorite lookout rather than patrolling constantly on the wing.

Mature males add a second layer of pattern to the wings: chalky-white pruinescent patches develop between the dark spots, so a flying male flashes brown-and-white in alternating pulses. Females and young males lack this white pruinescence and instead show pale yellow stripes running down the sides of a mostly brown abdomen.

This species is common and conspicuous across most of the continental United States and southern Canada, often the largest dragonfly patrolling a farm pond or lake margin in summer.

• Large, heavy-bodied dragonfly with three brown spots on each of the four wings (12 total)
• Mature males add white pruinose patches between the brown spots, giving a flickering black-and-white wing pattern in flight
• Body brown, with males developing pale blue-gray pruinescence on the abdomen with age
• Females and immatures show yellow lateral stripes along the abdomen and lack white wing patches
• Lookalikes: Widow Skimmer (Libellula luctuosa) has broader dark wing bases and a white subapical band rather than three discrete brown spots; Common Whitetail (Plathemis lydia) has only a single dark basal wing patch

Found across most of the continental United States and southern Canada, this skimmer favors open ponds, lakes, and slow-moving streams with unshaded shorelines and some emergent or floating vegetation. It tolerates a range of water quality and is common at farm ponds, reservoirs, and marsh edges. Adults are on the wing from late spring through summer, with timing shifting earlier in southern latitudes and later in the north.

Males are territorial, perching on grass stems, twigs, or bare ground near water and making short patrol flights to chase off rivals before returning to the same perch. Both sexes hunt small flying insects such as mosquitoes, midges, and other soft-bodied insects, snatching them out of the air with a basket formed by their spiny legs. As predators, adult skimmers help regulate populations of smaller flying insects around ponds and fields, while their aquatic larvae are important predators within pond food webs and prey for fish and wading birds.

Females lay eggs by tapping the tip of the abdomen onto the water surface while flying, often unaccompanied by the male, scattering eggs over open water or vegetation. Eggs hatch into aquatic nymphs (naiads) that live among submerged vegetation and detritus, breathing through internal gills and ambushing prey with an extendable hinged labium. Depending on climate, the nymph stage lasts one to two years and passes through numerous molts before the mature nymph climbs emergent vegetation, splits its skin, and emerges as a soft, pale teneral adult that hardens and colors up over the following days.