Identifying ticks in livestock: Part 1

Prof Maxime Madder, Prof Ivan Horak and Dr Hein Stoltsz look at three important tick species in South Africa and their effects on livestock, and offer tips for farmers on how they can identify these pests.

There are nearly 900 species of tick in the world, and while they differ from species to species, they have one thing in common: they are bloodsucking arachnids. There are two 'types': hard ticks and soft ticks. However, they are somewhat similar in appearance: they are relatively flat when not engorged, are not segmented, and have four pairs of legs. Each leg is covered in short, spiny hairs and has a claw at the end.

This helps the tick grasp blades of grass and leaves, as well as holding on to their hosts.

The tick feeds by attaching to the host with its mouthparts. It has two chelicerae, which pierce the host's skin. The two palps move out of the way during feeding, and the hypostome is a needle-like part that 'injects' into the host to feed.

The hypostome is barbed. These barbs point back towards the tick, which is why it is difficult to remove an attached tick without damaging the host's skin. The saliva secreted by the tick during feeding also acts like a cement, making it even more difficult to remove the tick from the host.

As the tick feeds, its body becomes engorged and it swells. Soft ticks do not swell as much as hard ticks, and female hard ticks tend to swell more than their male counterparts, as they store more blood for laying eggs. Male hard ticks swell very little, as the conscutum constricts swelling.

BONT TICKS