Lone Star tick (Amblyomma americanum)

How to identify it

• Adult female: reddish-brown body with one distinct, slightly iridescent white/cream dot in the center of the scutum (back) — the diagnostic 'lone star.'
• Adult male: darker reddish-brown with no single central dot; instead there are scattered white spots and streaks around the rear and outer margin of the body.
• Long mouthparts (a long capitulum) that clearly project forward — noticeably longer than the short mouthparts of Dermacentor 'dog' ticks; a useful clue on males, nymphs, and larvae that lack the dot.
• Festoons: a row of small rectangular blocks separated by grooves along the rear edge of the body, present in Amblyomma nymphs and adults.
• Rounded, teardrop-shaped body and relatively long legs; the overall look is 'roundish' rather than the flat, narrow silhouette of a blacklegged tick.
• Nymphs and larvae are unmarked and easily confused with other species — the white dot does not apply to them.

Size: Larva (six legs, the "seed tick"): about 0.5 mm, roughly a pinhead or grain of sand. Nymph (eight legs): about 1–1.5 mm, close to a poppy seed. Unfed adult: about 3–4 mm, roughly a sesame seed, with the female slightly larger than the male. Engorged (fully fed) female: swells dramatically to about 10–16 mm — pea- or small-grape-sized — turning slate-gray or olive; females may take a week to 10 days or more to fully engorge.

Where it lives & when

CDC maps the Lone Star tick as widely distributed through the Northeast, South, and Midwest of the United States. Its core, long-established range runs from Texas and Oklahoma eastward across the South-Central and Southeastern states to the Atlantic coast, and up the coastal plain into the mid-Atlantic and southern New England. Surveillance and university-extension data document ongoing northward and westward expansion — reported as far north as Maine and as far west as parts of Colorado and Wyoming — attributed partly to rebounding white-tailed deer populations. A county not marked "established" does not mean the tick is absent there.

Season: Active from spring through fall, with a longer season in the warm South. Adults are most active roughly April through late August; nymphs are common late spring into summer (about May–July); and larvae — the swarming "seed ticks" that can attach by the dozens or hundreds — peak in mid-to-late summer. All three biting stages (larva, nymph, adult) will bite people, and this species quests actively and moves quickly toward a host.

• Woodlands with dense, brushy undergrowth and the shaded transition zones between forest and field
• Tall grass, weedy field borders, fence lines, and overgrown trail edges
• Around animal resting and bedding areas — especially white-tailed deer and wild turkey habitat
• Leaf litter and low vegetation in humid, shaded ground cover
• Suburban yards and edges bordering woods or brush where deer and small mammals travel

Diseases the lone star tick can carry

Tick presence is not the same as personal disease risk. Not every bite transmits a pathogen.

Look-alikes

Honest confusion is common outside the adult-female stage. The American dog tick (Dermacentor variabilis) is a frequent mix-up: it is a similar size but has an ornate white-to-gray mottled/marbled shield rather than a single dot, and much shorter mouthparts — the female Lone Star's one clean central dot versus the dog tick's patterned shield is the tell. The Gulf Coast tick (Amblyomma maculatum), a close relative that overlaps in the Southeast, is larger with more extensive silvery ornamentation spread across the shield rather than a single spot. Blacklegged/deer ticks (Ixodes scapularis) are much smaller, darker, and have no white dot — worth distinguishing because people often fear Lyme, which the Lone Star tick does not transmit. Critically, male Lone Star ticks (streaks, not a dot) and all nymphs and larvae lack the star, so the classic marking only confirms adult females; use body shape, long mouthparts, and festoons for the other stages, and consider photographing the tick or asking a clinician or extension service for identification.