dispersal of ticks and tick borne diseases by birds - Lista fuglestasjon

Tick biology
Box II
Tick classification
(Hoogstraal and Aeschlimann, 1982)
Phylum
Arthropoda (Arthropods)
Subphylum
Chelicerata (Chelicerata)
Class
Arachnida (Spiders et cetera)
Subclass
Acari (Ticks and mites)
Order
Parasitiformes
Suborder
Ixodida (Ticks)
Family
Ixodidae (Hard ticks):
Prostriata: Ixodes
Metastriata: Amblyomma, Dermacentor,
Haemaphysalis, Hyalomma,
Rhipicephalus
Family
Argasidae (Soft ticks):
Argas, Ornithodorus
Family
Nuttalliellidae, only one species:
Nuttalliella namaqua
Hard ticks (Ixodidae) is a family in the
suborder Ixodida (Box II). As opposed to
the soft ticks, Argasidae, they have a
hard chitin shield (in males: scutum/in
females, nymphs and larvae: scutellum).
Ixodidae have three mobile instars after
hatching from eggs: larva, nymph and
adult (Figure 4). In all of the mobile
instars, the individual needs to have a
blood-meal from a vertebrate host. They
feed only one time before moulting to
the next instar. Most often this occurs on
three different hosts. After engorging,
which results in the multiplication of
their weight by 80-120 times, the
females produce 1000-10,000 eggs
(Hillyard, 1996). Before this study, there
were twelve species of hard ticks (Acari:
Ixodidae) found in Norway (Mehl 1983;
Lillehaug, 2003).
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The abundance of questing ticks will vary
during the day and from day to day because
of responses to changes in the microclimate.
Hubálek et al., (2003 a) found a positive
correlation between tick activity and
temperature, and a negative correlation
between tick activity and relative humidity.
Abundance will also vary from year to year
due to survival through the last year’s
humidity and temperature. Finally,
abundance can vary through decades because
of changes in vegetation and availability of
host animals.
Biology of the ticks found in this study
(Paper III).
Ixodes ricinus (sheep tick) is the only
Norwegian tick species that normally act as a
vector for diseases in humans and domestic
animals. Additionally, it is the only tick
species commonly questing on the ground in
Norway. This tick is widespread across
Europe and is found along the coastal areas
of southern Norway, north to Brønnøysund
(latitude N65º30’), in the county of
Nordland. It is a three-host tick and needs to
feed once between each instar, in order for
the female to produce eggs. Larvae and
nymphs can parasitise mammals of all sizes,
along with birds and reptiles. I. ricinus seems
able to parasitise any bird or mammal species
occurring within its habitat and distributional
range, but it cannot complete its life cycle on
small mammals and birds because the adults
need hosts as large as or larger than cats
(Jaenson et al., 1994). The blood meal for
this tick lasted three to four days for larvae
and nymphs in an experiment with great tits
(Parus major) (Heylen and Matthysen 2010).
As adult I. ricinus rarely infest passerine
birds, there are no data for the duration of
feeding of adult I. ricinus in birds; however,
in a study of rabbits, the mean feeding time
was seven days in the first feeding
experiment for rabbits that were not
immunised against I. ricinus. Rabbits
typically mount an immune reaction to ticks,
leading to a prolonged feeding period. In the