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Tick Feeding

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Blood Feeding

Mouthparts

The mouthparts of hard ticks are readily visible from above; the mouthparts of soft ticks are not. Both families show three visible components: the two outside jointed parts are the highly mobile palps; between these are paired chelicerae, which protect the center rod-shaped structure, the hypostome.

Figure 1: Diagram of tick feeding.
Tick A represents a superficial species, such as the American Dog tick (Dermacentor variabilis).
Tick B represents a more deeply attached species, such as the Lone Star tick (Amblyomma americanum).
The leg bearing section is denoted the podosoma while the head region, the gnathosoma.

   

The palps move laterally while the tick is feeding and do not enter the skin of the host. The rough hypostome has many beak-like projections on it.
This is the structure which plunges into the host's skin while feeding. The backward-directed projections prevent easy removal of the attached tick.

In addition, most hard ticks secrete a cement-like substance produced by the salivary glands which literally glues the feeding tick in place; the substance dissolves after feeding is complete.

Periods of Feeding

Hard ticks

Hard ticks feed for extended periods of time on their hosts, varying from several days to weeks, depending on such factors as life stage, host type, and species of tick.

The outside surface, or cuticle, of hard ticks actually grows to accommodate the large volume of blood ingested, which, in adult ticks, may be anywhere from 200-600 times their unfed body weight.

Soft ticks

Soft ticks feed several times during each life stage, and females lay multiple small batches of eggs between blood meals during their lives.

Soft ticks feed for short periods of time on their hosts, varying from several minutes to days, depending on such factors as life stage, host type, and species of tick. The feeding behaviour of many soft ticks can be compared to that of fleas or bedbugs, as once established, they reside in the nest of the host, feeding rapidly when the host returns and disturbs the contents.

The outside surface, or cuticle, of soft ticks expands, but does not grow to accommodate the large volume of blood ingested, which may be anywhere from 5-10 times their unfed body weight.

The time to completion of the entire life cycle is generally much longer than that of hard ticks, lasting over several years. Additionally, many soft ticks have an uncanny resistance to starvation, and can survive for many years without a blood meal.

   

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