Know Your Vector: Common Ticks of Pennsylvania

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- [Michael] There are more than 900 species of ticks worldwide, and of those, there are around 25 species of ticks that are found in Pennsylvania.

While this sounds like a lot, only four species regularly bite people in companion animals.

Black-legged ticks, American dog ticks, lonestar ticks, and brown dog ticks.

A fifth species, Asian longhorned ticks, were recently found in the state and should be watched for.

Black-legged ticks can be distinguished from other ticks by their coloration.

The mouth parts, legs, and scutum are dark brown to almost black.

Males appear to be entirely dark-colored because the scutum, which is a hard plate behind the head, covers most of the abdomen.

The scutum of females is smaller, and the softer abdominal cuticle is usually red in color.

In addition to color pattern, black-legged ticks can be identified by the absence of festoons, which are rectangular ridges along the posterior of the abdomen, long palps, and absence of eyes.

American dog ticks are distinctive due to their ornate color pattern of dark red with white reticulations.

This pattern is restricted to the scutum and is more readily apparent in males where the scutum covers most of the abdomen.

Because the scutum of female ticks is smaller, the red and white reticulated pattern can be more difficult to see in female American dog ticks.

However, it is still present and can be used to identify even fully engorged females.

In addition to color pattern, American dog ticks can be distinguished by the presence of festoons, short palps and eyes.

Adult female lone star ticks are distinctively colored with dark red legs, mouth parts and body with a single white spot at the tip of the scutum.

No other ticks in the northeastern United States have this color pattern.

Adult male lone star ticks are somewhat harder to identify.

They're also dark red in color, but instead of a single white spot, they usually have four white to off-white lines at the corners of the scutum.

These white lines may be absent, so the tick is entirely dark red.

In addition to color pattern, lone star ticks can be distinguished from other species by the presence of festoons, long palps and eyes.

Brown dog ticks are dark brown and inornate, although they can have some darker brown to almost black markings that may be difficult to see.

Brown dog ticks can be distinguished from black-legged ticks by the presence of festoons along the posterior edge of the abdomen.

The shape of the leg segments can help identify brown dog ticks from other species as well.

There appear to be constrictions between the segments, which makes the segmentation quite obvious, almost as if the legs were balloon animal legs.

The most definitive characteristic that identifies brown dog ticks is the basis capituli.

This can be difficult to see without the added magnification, but it is hexagonal in shape and extends laterally beyond the palps.

Brown dog ticks can also be distinguished from other species by the presence of festoons, short palps that are not longer than the basis capituli, and presence of eyes.

Asian longhorn ticks are brown and inornate.

They have festoons along the posterior edge of the abdomen and are somewhat similar in appearance to brown dog ticks.

Asian longhorn ticks can be distinguished from brown dog ticks based on the shape of the basis capituli and the palps.

In Asian longhorn ticks, the basis capituli are rectangular and the palps extend laterally beyond it.

In brown dog ticks, the basis capituli are hexagonal and extend laterally beyond the palps.

Asian longhorn ticks can be distinguished from other species by the presence of festoons, short palps that are longer than the basis capituli, and the lack of eyes.

Take a look at these ticks.

Can you identify them?

Compared to each other, the handful of ticks that regularly bite people in companion animals are distinct and usually easy to identify.