The Thirteen-spotted Lady Beetle is native to North America. Its wing covers are reddish orange with thirteen black spots in total. This species is found primarily in wet meadows and marshes, lake shores, and flood plains. It feeds on aphids and is most active from May to September.
Listed as Critically Imperiled in the Prince Edward Island; Imperiled in Nova Scotia; Apparently Secure in New Brunswick, Ontario, Saskatchewan, Alberta, Yukon, and the Northwest Territories; and Secure in British Columbia.
This species has been in sharp decline, and its range is shrinking. This may be due to land use changes and the introduction of non-native species, many of which heavily utilize human-altered landscapes.
Thirteen-spotted Lady Beetle populations have declined over several decades. Scientists believe that introduction and establishment of the Seven-spotted Lady Beetle is one of the primary causes.
The Thirteen-spotted Lady Beetle is 4.5 to 6.5 mm in length and is oblong in form.
- Head: Black with a pale to yellow blaze between the eyes.
- Pronotum: Black, with a thick pale to yellow margin wrapping around the sides and front of the pronotum. The margin is thicker on the sides of the pronotum. There are two black spots (one on each side of the pronotum) in the margin, which are sometimes joined to the central black patch.
- Elytra: Yellow to orange with 13 black spots (6 per elytron and one at the top, near the pronotum, which spans the suture). Some of the spots fuse together occasionally.
- Legs: Black at the top, light brown to orange at the bottom.
- Often confused with: Convergent Lady Beetle, Variegated Lady Beetle, Asian Lady Beetle, Nine-spotted Lady Beetle, Five-spotted Lady Beetle.
Reed beds and marshes. Can also be found in meadows, gardens, and agricultural fields.
Distribution is holarctic (across the Northern Hemisphere), with one subspecies occurring in North America. In North America, the Thirteen-spotted Lady Beetle range spans from coast to coast, north to Alaska and south to Texas.
Thirteen-spotted Lady Beetles sometimes aggregate on lake shores before winter hibernation and after they emerge from their overwintering sites. Thirteen-spotted Lady Beetles are active between April and October, and are most frequently encountered between July and August. Average development from egg to adult can take approximately 20 and 28 days, at 31 degrees C and 25 degrees C, respectively.
You can find more information about Thirteen-spotted Lady Beetles using the following links:
Visit the iNaturalist Observation Map and Occurrence Records to find out where Thirteen-spotted Lady Beetles have been seen in Vermont.