Blacklegged (deer) ticks

Figure 1

This figure shows the size and pattern of:

• unfed adult blacklegged ticks (top row)
• adult American dog (wood) ticks (bottom row)

American dog ticks are larger than blacklegged ticks:

• female American dog ticks are about 0.5 cm long
• female blacklegged ticks are about 0.3 cm long

The back of American dog ticks has a unique pattern, while the back of blacklegged ticks is not patterned.

Figure 2

This figure shows the life stages of a blacklegged tick that has not fed:

• larva (1)
• nymph (2)
• adult male (3)
• an adult female (4)

Figure 3

This figure shows 5 female blacklegged ticks in different stages of feeding.

Unfed female ticks are dark reddish-brown. They:

• become paler brown to yellow as they start to feed
• become greyish as they continue to feed
• are dark grey-brown when fully fed

As they feed, the tick's stomach gets bigger. The tick grows from approximately 0.3 cm when unfed to 0.6 cm when partially fed.

When fully fed, the tick is:

• about 1cm long
• egg-shaped

Figure 4

Three nymphs of the blacklegged tick are shown in different stages of feeding.

The unfed nymphal ticks are:

• very small (0.15 cm long)
• grey-brown in colour

As they feed, their stomach grows and gets darker. When they are fully fed, the nymph is:

• about 0.3 cm long
• almost black in colour
• egg-shaped