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The Egg Mating of hard ticks usually
occurs while they are on the host animal. Afterwards the female drops to
the ground and, after a brief pre-oviposition period of three to 10 days,
begins to deposit eggs on or near the earth. The female hard tick feeds
once, lays one large batch of eggs sometimes numbering in the thousands,
and dies. Most of the soft ticks engorge with blood several times and
deposit about 20 to 50 eggs in a batch after each blood meal. Eggs hatch
in two weeks to several months, depending upon temperature, humidity and
other environmental factors.
The
Larva The
larvae, or "seed ticks," have only six legs, and the sexes are
indistinguishable. Their chances of attaching to a host are precarious,
sometimes resulting in prolonged fasts.
Despite tolerance to
starvation, a very high percentage die. Some individuals climb on
vegetation, waiting for a small rodent to pass within reach. Some actively
seek a vertebrate host, being guided by the sent of the animal. After a
blood meal, the engorged larvae usually drop to the soil and molt to the
eight-legged nymph stage. The larvae of one-host ticks remain on the host
to molt.
The Nymph The nymph has eight legs like
the adult but has no genital opening. This stage also must undergo a
critical waiting period for a suitable host. After engorgement, the nymph
drops from the host, molts, and becomes an adult. Nymphs may rest for long
periods before becoming adults. Some species of hard ticks live less than
one year while others live three yearsor more. Each time a tick leaves its
host it risks its survival on on finding another host. Some species have
the advantage of molting on the host. For example, the cattle tick is a
one-host tick. Multiple-host tick species are able to exist because of
their great reproductive capacity and their ability to survive for a long
time without food.
Hard ticks have only
one nymphal instar, the nymph becoming an adult after molting. Soft ticks
may have several nymphal instars.
The
Adult
Typically, the nymph molts after engorgement and becomes an adult.
Sex then is distinguishable for the first time as the female hard tick
differs from the male in having a small scutum. The sex of soft ticks may
be determined by the shape of the genital opening located between the
second pair of legs. In male soft ticks the genital opening is almost
circular, while it is oval and definitely broader than long in female
specimens. Unlike mosquitoes, both male and female hard ticks are blood
suckers, and both require several days feeding before copulation. After
the male hard tick becomes engorged, he usually copulates with one or more
females and then dies. Following copulation, the female tick drops to the
ground. The eggs require several days to develop. Then she begins
oviposition. After a few more days, her life's mission accomplished, the
spent female hard tick also dies. The female soft tick may lay several
small batches of eggs but she requires another blood meal before each
episode of oviposition.
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