White Spots on the Underside of Ticks

Ever seen a tick that had a White Spot on its Underside? 👀  

We actually get a lot of these tick questions submitted to us from folks thinking that the white spot is that of the Lone Star tick. Are they right? NOPE! Well, not necessarily, at least…

The classic “white spot” of the adult female Lone Star tick is on TOP of the tick, on the scutum (dorsal shield), not the belly. The white spot you see on the underside of the tick is actually an accumulation of Guanine Crystals in the tick’s rectal sac as the tick starts to digest blood.

In unfed ticks, the rectal sac would be empty, so there wouldn’t be a white spot. Interestingly enough, this white spot can appear in any species of partially or fully engorged tick; however, oddly enough happens to appear most frequently in Lone Star ticks.

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Tick with White Spot on Underside