Fróðskaparrit - 31.12.2000, Page 132

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CHECKLIST OF THE FLEAS ON THE FAROE ISLANDS
ersen, Dorete Bloch and Gert Brovad for
various services rendered.
Altogether we found more than 5000
fleas, of which 475 were slide-mounted and
these are kept at the Museum of Natural
History in Tórshavn.
The life ofaflea
Fleas are small (1-8 mm long) wingless in-
sects. As adults their bodies are strongly
compressed laterally and so contrary to oth-
er insects are always pictured from the side.
They are heavily sclerotised, hairy and
shiny and normally light brown to almost
black. Fleas are parasitic in the adult stage
only, sucking blood from birds and mam-
mals. In low temperatures adult fleas can
exist for long periods without food. The fe-
males produce up to 100 eggs during their
lifetime - not in one go though, but a few
after each meal.
The larvae are' legless and eyeless with
few, but strong bristles and biting mouth-
parts; they are not parasitic, but feed on or-
ganic matter, which they fínd in the nest or
dwelling place of the host. They can also be
called indirect parasites, as the only partly
digested blood from the adult fleas’ excre-
ments is a vital ingredient in the food of the
larvae (Brinck-Lindroth, 1983) The larvae
are lively and quickly disperse to an envi-
ronment, which is suitable - generally they
prefer a humidity between 75% and 90%.
They moult twice and the larval stage nor-
mally lasts approx. one to two weeks.
The free pupa is contained in a co-
coon.The pupa stage normally lasts from
one to two weeks, but if the cocoon is kept
completely still, the flea will often stay in-
side the cocoon for up to one year. The
slightest movement will cause it to leave
the cocoon immediately, which is why
sometimes empty houses are found to have
whole armies of hungry fleas.
Method
Thus (Fowler, J.A. and Cohen, S., 1983)
fleas were either collected from the hosts as
adults for example when birds were ringed,
they were also checked for fleas and in the
same manner mammal fleas were caught
from mice and cats. However most fleas
were hatched from larvae - i.e. nesting ma-
terial was deposited in polythene bags and
regularly checked for fleas.
In 1997 for instance nesting material was
collected from the following bird nests:
Puffin (Fratercula arctica) - 25 nests from Seyðtorvu,
Viðoy
Puffin (Fratercula arctica) - 15 nests from Hvannrók,
Trøllanes
Eider (Somateria molissima) - 15 nests from Sumbiar-
hólmur
Eider (Somateria molissima) - 5 nests from Nólsoy
Greylag Goose (Anser anser) - 3 nests from Leitisvatn
Kittiwake (Rissa tridactyla) - 2 nests from Stóra
Dímun, from one of which hatched 1234 fleas (!).
Lesser Black-backed gull (Larus fuscus) - 5 nests from
Nólsoy
Lesser Black-backed gull (Larus fuscus)- 1 nest from
Toftir
Feral Pigeon (Columba livia) - 2 nests from a
pigeonloft in Tórshavn
Starling (Sturnus vulgaris) - 2 nests from Sumba
Starling (Sturnus vulgaris) - 3 nests from Nólsoy
Starling (Sturnus vulgaris) - 1 nest from Sandavágur
Starling (Stumus vulgaria) - 1 nest from Stóra Dímun
Fielđfare (Turdus pilaris) - 1 nest from Klaksvík
Blackbird (Turdus merula) - 1 nest from Klaksvík
House Sparrow (Passer domesticus) - 12 nests from
Nólsoy
House Sparrow (Passer domesticus) - 3 nests from
Viðareiði
Wren (Troglodytes troglodytes) - 1 nest from Mykines