Why does a tick turn white? - briefly
A tick appears white after feeding because its abdomen expands, thinning the cuticle and exposing the pale hemolymph beneath. The same pallor can occur after death as the body dries and loses pigment.
Why does a tick turn white? - in detail
Ticks appear pale when they have recently fed, are preparing to molt, or are experiencing environmental stress. After a blood meal, the abdomen expands dramatically; the cuticle stretches and becomes translucent, allowing the underlying hemolymph to reflect light and give a whitish hue. This coloration fades as the tick digests the blood and the cuticle re‑darkens.
Molting also produces a light shade. During the ecdysis cycle, the old exoskeleton separates from the new one, and the freshly formed cuticle is initially soft and lightly pigmented. Until sclerotization completes, the tick looks almost white.
Dehydration or exposure to low humidity can cause the cuticle to lose moisture, increasing light reflectance and creating a pallid appearance. In extreme cases, death leads to desiccation; the body becomes chalky and whitish as internal fluids evaporate.
Temperature shifts influence pigment expression. Cold environments suppress melanin synthesis, temporarily lightening the surface. Warm conditions accelerate pigment production, restoring darker tones.
The combination of these physiological processes—blood intake, molting, water loss, and temperature effects—explains the transient whitening observed in ticks.