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150 J. E. Brittain Nemzlrella picteti Klapalek In common with N. cinerea, N. bicteti is recorded as having a long flight period and being univoltine (Hynes 1941, Brinck 1949, Khoo 1964, Ulfstrand 1969 and Lavandier & Dumas 19711. However. as was the case with N. cinerea, ihere is evidence that the species takes two years to complete its life cycle in the mountain localities in Vassfaret and at Finse. As numbers were small, results from Lakes 1171, 1205 and 1220 were combined in Fig. 15. In addition the results of hatching eggs and rearing the nymphs from Lake 1220 at a temperature of 10' C showed that even at 10' C the nymphs did not attain the size of the field population during the autumn, indicating that the field population probably hatched before ice break. In a Pyrenean stream, Lavandier & Dumas (1971) found that the population of N. picteti was bimodal prior to emergence in February, but they postulated that the smaller nymphs emerged the same year, in October and November. Such a long emergence period is impossible above the tree line in Norway owing to the long duration of ice cover. Also water temperatures are lower in the Norweeian " mountains. The presence of a life cycle taking more than one year is a fairly common feature in the Setipalpia, but previous studies of the Filipalpia have shown them to be almost solely univoltine. Only three species, Nemoura cinerea (Khoo 1964), Leuctra nigra (Khoo 1964), and L. ferruginea (Harper 1973) have been reported as being semivoltine. However, if a longer life cycle were to exist in the European Filipalpia, N. picteti and N. cinerea, - both widGpread species with long emergence periods and often with considerable size variation within a single population, would be obvious candidates. Leuctra fusca L. Previous investigations (Hynes 1941, Brinck 1949, and Ulfstrand 1968) have shown that in L. fusca most growth is accomplished during the summer months, and it is therefore a typical aestival species (Brinck 1949). Data from Setten fit in well with these earlier studies, mature nymphs occurring at the end of July, whereas no nymphs were found in May or September. Capnia atra Morton As small nymphs are present during the autumn and emergence takes place at or immediately prior to ice break, considerable growth must occur under the ice. There is, however, according to previous investigations (Brinck 1949, Svensson 1966 and Benedetto 1973) a pause in growth during the middle of the winter. Around Finse, imagines and mature nymphs occurred during June and the first half of July. By the end of August small nymphs, 2-3 mm long, were present in Sandaavatn, Lake 1430, and Flakavatn, but it was not until the end of September that nymphs of similar size were present in the other Finse localities, by which time nymphs from the three former localities were nearly 5 mm long. This difference in nymphal growth rate andl or egg incubation period may be a function of temperature and the length of the ice-free period, but this point needs further investigation before a definite judgement can be made. Even in the most extreme habitats, C. atra was univoltine. A female from Lake 1430 laid eggs which hatched over a period of 7-13 days at 4' C (Lillehammer, personal communication). Imagines were present in the field long after emergence had taken place. up to 6 weeks in some cases. Diura bicaudata (L.) Early investigations suggested that D. bicaudata was univoltine with a very short egg incubation period (Hynes 1941, Brinck 1949), but later investigations combining laboratory and field studies (Khoo 1968, Schwarz 1970) have shown that it may have both one and two-year life cycles, depending on the presente or absence of diapause in the egg stage. In the localities investigated in the present study a two-year life cycle is the most likely, small nymphs being present in collections at the same time as or shortly after emergence of the adults. GENERAL DISCUSSION Within each area and also generally there was a correlation between the concentrations of calcium and magnesium. The correlation coefficient (r) for al1 the localities taken to-
Fig. 16. The relationship between the length of the ice-free period and the maximum temperature recorded in the locality during sampling. gether was 0.86. As may be expected the correlation was stronger within the three srnaller, more geologically homogeneous areas, than in the larger and more varied Oslo region. Calcium concentrations and conductivity were also correlated (r = 0.93), although as with calcium and magnesium the regression coefficients for each area had somewhat different values as a result of variations in the proportion of the various chemical components. Therefore in future investipations " of this nature, especially within a particular area, it may be necessary to measure only one of the three factors, calcium magnesium and conductivity, rather than al1 three. The calcium and p~ values show a similar relationship to that found for total hardness and pH by Okland (1969) from a survey of severa1 hundred lakes over the whole of Norway. The length of the ice-free period plays an important role in the temperature regime of a freshwater habitat. In the present investigation there was a strong correlation between the length of the ice-free period and the maximum temperature recorded in the locality (r = 0.86) (Fig. 16). The temperature Ephemerofitera and Plecoptera 15 1 of the ice-free period varied from as little as three months at Finse to nearly eight months in some lowland localities. The actual period is determined by a combination of factors, of which size, altitude, and winter precipitation are important. The number of s~ecies and their abundance varies for both Ephemeroptera and Plecoptera with changes in vegetation. That the subalpine region is especially important in this respect is well seen in the Heimdalen area (Table 11). The mean number of Ephemeropteran species in the different vegetation repions . of the four studv areas was as follows: high alpine zero, mid-alpine 0.2, low alpine 0.7, subalpine 3.3 and boreal 4.8 species. Thus the limit for lentic Ephemeroptera was in the mid-alpine region and even in the rnidalpine and low alpine regions there were very few species capable of colonising lentic localities. These are principally summer growing species, such as Baetis macani and Siphlonurus lacustris. However, once in the subalpine there was a considerable increase both in species and abundance. For example, in the same water course in Heimdalen there was a fourfold increase in the number of species and approximately a hundredfold increase in the number of Ephemeropteran nymphs frorn the low alpine to the subalpine. There was a further increase in the boreal zone, especially in the more lowland localities where 8 or 9 species were often present. The dramatic change in the subalpine region is no doubt a result of a cornbination of biotic and abiotic factors, of which tempera- values are, however, the maximum of severa1 spot readings, but the placement of maximumminimum thermometers in eight localities '0 EPHEMEROPTERAN SVECIES liX during the sumrner of 1971 showed that as the maximum spot ternperature increased, so the absolute maximum rose. The relationship between them was good (r = 0.96). The length Fig. 17. The relationship between the length of the ice-free period and the number of Ephemeropteran species recorded from the locality.
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Page 6 and 7: Dry Weight , mg. Fig. 7. Correlatio
Page 8 and 9: Table 11. Caloric values per g dry
Page 10 and 11: Talbe IV. Oxygen consumption given
Page 12 and 13: etween the sexes during the respira
Page 14 and 15: 128 A. Fjellberg Fig. 2. A. sefiten
Page 16 and 17: 130 A. Fjellberg HABITATS Until now
Page 18 and 19: 132 L. Semme the autumn. The prelim
Page 20 and 21: '~0~1-0611 '96 'lourouy 'uu3 's3asu
Page 22 and 23: 136 J. E. Brittain Fig. 1. The loca
Page 24 and 25: 138 J. E. Brittain period was longe
Page 26 and 27: 140 J. E. Brittain Table 11. Ph~sic
Page 28 and 29: 142 J. E. Brittain Table IV. Physic
Page 30 and 31: 144 J. E. Brittain EPHEMEROPTERA Am
Page 32 and 33: 146 J. E. Brittain 0-3 NYMPHS I I 1
Page 34 and 35: 148 J. E. Brittain 1-3 NYMPHS 01 I
Page 38 and 39: 152 J. E. Brittain ture and the inc
Page 40 and 41: (Nord-Norwegen) (Trichoptera, Pleco
Page 42 and 43: from anoxia. Drops of haemolymph we
Page 45 and 46: Notes on little known spiders in No
Page 47 and 48: Symphyla and Pauropoda from two con
Page 49 and 50: Symphyla and Pauropoda 163 Table 11
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Page 56 and 57: 170 T. R. Nielsen Table 1. A compar
Page 59 and 60: Abundance and diversity in the faun
Page 61 and 62: Nocturnal moths 175 Table 1. Number
Page 63 and 64: Nocturnal moths 177 Grimstad Amli 1
Page 65 and 66: Nocturnal moths 179 Am/i. Norway 19
Page 67 and 68: Nocturnal moths 181 Grimstad, Norwa
Page 69 and 70: Nocturnal moths 183 %60 50 40 30 20
Page 71 and 72: Spinosellina forms of Sminthurides
Page 73 and 74: A constant pressure microrespiromet
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Page 78 and 79: 192 F. E. Klallsen The specimens fr
Page 80 and 81: 194 F. E. Klausen REFERENCES Ardii,
Page 82 and 83: 196 A. Lillehammer present in Norwa
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200 A. Lillehammer Fennoscandian co
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202 A. Lillehammer parts of the are
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204 A. Lillehammer carnivorous spec
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Table IV. Species distribution, in
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Table V. Species distribution in se
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210 A. Lillehammer The bottom of th
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212 A. Lillehammer Blatjemn Diura b
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Table VII. Species distribution in
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Z 0 ...... ~ '"s' '" ~ .... '.xl ~
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Table IX. Species distribution in s
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220 A. Lillehammer same latitude as
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222 A. Lillehammer Table XI. The pH
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224 A. Lillehammer These species se
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226 A. Lillehammer Table XVI. The s
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228 A. Lillehammer Fig. 22. Stream
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230 A. Lillehammer Fig. 25. Distrib
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238 A. Lillehammer high altitude la
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244 A. Lillehammer streams and rive
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246 A. Lillehammer Blies (1953, 195
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248 A. Lillehammer streams are to a
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250 A. Lillehammer Muller, K. 1955.
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252 Bokanmeldelser produserende, en
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N orsk Entomologisk Tidsskrift Norw
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