o .eg an Jo of En1tomol0lD' - Norsk entomologisk forening

Some studies on Macrolepidoptera in coastal heathland
habitats in Western Norway
TROND ANDERSEN
Andersen, T. 19'82, Some studies on Macrolepidoptera in coastal heathland habitats in Western
Norway, Fauna nom Ser, B, 29,85-104,
Between 1975 and 1980 some 225 species in 11 families and more than 25,000 specimens
were collected on northern Sotra, mainly in light traps, but also with nets and as larvae, The
two important families were Noctuidae with 105 species and Geometridae with 85 species,
Mythimna unipuncta (Haworth, 1809) was recorded for the first time in Scandinavia,
Based on light trap catches the composition of the Macrolepidoptera fauna in the two
main heathland habitats, the Calluna- heath and the grassland, were compared using various
species diversity indices, The Calluna- heath had lowest species diversity due to the
poor flora, In both habitats species diversity was higher in Noctuidae than in Geometridae,
Similarity indices showed that the number of species common to both habitats was highest
in Noctuidae which might reflect a higher dispersal potensiaL The ranking of the dominant
species was more similar in Geometridae indicating the importance of Juniperus as foodplant
in both habitats,
Thera cognata (Thunberg, 1792) was the dominant species in both habitats, while Lycophotia
porphyrea (Denis & Schiffermuller, 1775) ranged second in the Calluna- heath and Cerapteryx
graminis (L, 1758) on the grassland, Most of the abundant species are common
and widespread in Western Norway, but Pachycnemia hippocastanaria (Hubner, 1799) and
Stilbia anoma/a (Haworth, 1812) are typical for the coastal heathlands,
The flight periods of the abundant species are given, The median day of the flight generally
occurred earlier in the males than in the females, The sex-ratio in the light trap catches
differed strongly in favour of males,
Trond Andersen, Dept, of Systematic Zoology, Museum of Zoology, N-5000 Bergen, Norway,
INTRODUCTION
The heathlands in Western Norway are at the
northern border of the typical West European
lowland heaths (Gimingham 1976), These
• heathlands are situated in the oceanic and suboceanic
regions of Western Europe, characterized
by a mild temperate climate with relatively cool
summers and mild winters. As in most parts of
Western Europe the formation of lowland
heaths in Western Norway is probably due to
activities of man. About 2000 years ago the coast
of Western Norway was covered with pine
forests, which later were cut down to give grazing
land to the livestock (Kaland 1974). On
'",
poor and shallow soils the typical heath developed,
and with it a characteristic, rather marginal
type of farming, mainly based on sheep. Grass­
., land evolved in places with richer and deeper
'"
soils. To prevent the recolonization of trees and
to stimulate the growth of young nutritious shoots
on the Cal/una, the heaths were burned
every tenth year.
Fauna norv, Ser, B 29,85-104, Oslo lQ82,
During the last century, old farming habits
have changed. As a result old Cal/una- heath is
today the dominant vegetation type, in several
places also replacing grassland. Seedlings of
Pine, Pinus silvestris, and decidious trees like
Mountain Ash, Sorbus aucuparia, and Birch,
Betula pubescens, are now allowed to invade the
heathlands. Several municipalities along the
West Coast also have programs for vegetating
the heathlands with foreign coniferous species.
The coastal heathlands in Western Norway therefore
gradually change, and in some areas the
typical heaths have already disappeared.
In recent years the lowland heaths of Western
Europe have attracted much attention, particularly
among botanists (e.g. Gimingham 1976). In
Western Norway the «Lindasprosjektet» has
worked on the ecology of heathlands (Mortensen
1974) including surveys of invertebrates
(Hauge 1976, Solh0Y et al. 1981).
Larvae of Macrolepidoptera are herbivorous
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