Náttúrufræðingurinn - 1975, Blaðsíða 12

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NÁTTÚRUFRÆÐINGURINN
Otto, C., 1971: Growth and population movements of Potamophylax cinguíatus
(Trichoptera) larvae in a South Swedish stream. Oikos 22: 292—301.
Rist, Sigurjón, 1974: Efnarannsókn vatna. Vatnasvið Hvítár-Ölfusár. Einnig
Þjórsá við Urriðafoss 1973. Fjölr. Orkustofnun, Rannsóknarstofnun Iðnað-
arins. Reykjavík. 11 pp.
Scott, D., 1958: Ecological studies on the Triclioptera of the River Dean,
Cheshire. Arch. Hydrobiol., 54 (3): 340—392.
Svensson, B. IV., 1972: Flight periods, ovarian maturation, and mating in Tri-
choptera at a South Swedish stream. Oikos. 23: 370—383.
Tjeder, B., 1964: Neuroptera, Trichoptera and Diptera-Tibulidae from Iceland
with a redescription of Rhabdomastix parva Siebke. Opusc. Ent., 29 (1—2):
143-151.
Ulmer, G., 7909: Die SuBwasserfauna Deutschlands. Pts. 5—6. Triclioptera.
Jena. 326 pp.
SUMMARY
Potamophylax cingulatus (Stephens) (Trichoptera: Limnephilidae)
recorded from lceland
by
Gisli Már Gislason
Department of Zoology, University of Newcastle upon Tyne, England.
Potamophylax cingulatus (Stephens) was collected for the first time in Iceland
on August 2, 1971. During the spring and the summer of 1974 it was found in
nearly all rivers and brooks investigated in East and North-east Iceland (Fig.
2). P. cingulatus also occurs in estuaries and lagoons which are slightly saline.
In one lagoon the salinity was found to be 1.2%0. The species had a flight period
from the end of June until early September during 1974. Pupae were found
from late May to August 1974, larvae until late June, and eggs were found in
early August. Later stages in the life cycle of P. cingulatus appear earlier in
the year in Iceland than in England (Scott 1958, Crichton 1971) and S-Sweden
(Otto 1971, Svensson 1972). Tliis could be an adaptation to colder, and perhaps
more unsuitable, aulumns for the adults of P. cingulatus in Iceland than else-
where the species occurs.
Where P. cingulatus larvae were found, the caddis larva Apalania zonella
Zetterstedt did not usually occur. As shown in fig 2, P. cingulatus and A. zonella
were found together only in four streams. Three of them were at the known li-
mits of the distribution of P. cingulatus. By comparing the ionic composition of
streams with A. zonella and P. cingulalus, and because of the fact tliat botli
species were found in brackish water (fig. 4), it is thouglu unlikely that water