| 11. |
- Anderbrant, Olle
(författare)
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Survival of parent and brood adult bark beetles, Ips typographus, in relation to size, lipid content and re‐emergence or emergence day
- 1988
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Ingår i: Physiological Entomology. - : Wiley. - 0307-6962 .- 1365-3032. ; 13:2, s. 121-129
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT. This study investigated a possible trade‐off between bark beetle reproductive effort and future survival. Parent adult Ips typographus (L.) (Coleoptera: Scolytidae) were collected when they re‐emerged from a laboratory culture after completing their first brood and held at constant temperatures of 4 or 25oC. As a comparison, emerging brood adults were collected and held at 25oC. The longevity of the beetles was related to when they re‐emerged or emerged (measured in days since parent introduction) and to their size (pronotal width), fresh weight and lipid content at collection, by multiple regression analysis. The expression (fresh weight x pronotal width ‐2.6), used as an estimate of lipid content of the living beetles, was significantly correlated (r=0.67, P<0.001) with the actual (extracted) lipid content. At 25oC, fat content was the variable most strongly correlated with survival time in all beetle groups except parent females. In both parent and brood females, re‐emergence or emergence day, respectively, contributed significantly to the explanation of survival time, whereas pronotal width and fresh weight never contributed significantly to the regression equation. At 4oC, fat content was not estimated but, re‐emergence day was negatively correlated with survival time. In conclusion, beetles with high fat content and re‐emerging or emerging early have longer expected survival than beetles leaving the log later or containing less fat. This means that females laying a large first brood might suffer a somewhat higher mortality than females laying a smaller brood.
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| 12. |
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| 13. |
- Andrén, O., et al.
(författare)
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Barley straw decomposition with varied levels of microbial grazing by Folsomia fimetaria (L.) (Collembola, Isotomidae)
- 1985
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Ingår i: Oecologia. - : Springer-Verlag New York. - 0029-8549 .- 1432-1939. ; 68:1, s. 57-62
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Tidskriftsartikel (refereegranskat)abstract
- Folsomia fimetaria (L.) were added (0, 5, 10, 20 animals) to 0.100 g barley straw which had been inoculated 10 days (244 h) earlier with a natural soil microflora. Respiration (CO2 evolution) was monitored continuously. Mass loss, fungal standing crop (total and FDA-active), bacterial and protozoan biomass were estimated 42 days (1,000 h) after microbial inoculation. The degree of surface cover by hyphae was surveyed at regular intervals. No significant differences (P>0.05) were found in respiration, mass loss or microbial biomass, but the density of surface hyphae were reduced by addition of Collembola. Fungal production was low, less than 5% of the estimated microbial production, and could not account for all collembolan growth during incubation. F. fimetaria appeared to consume mainly bacteria and protozoa, and had little impact on carbon mineralization.
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| 14. |
- Arnebrant, Kristina, et al.
(författare)
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Copper Tolerance of Microfungi Isolated from Polluted and Unpolluted Forest Soil
- 1987
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Ingår i: Mycologia. - : Informa UK Limited. - 0027-5514. ; 79:6, s. 890-895
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Tidskriftsartikel (refereegranskat)abstract
- Microfungi were isolated from unpolluted and copper polluted forest soils and their tolerance was tested on agar plates. Species from polluted sites were usually tolerant to Cu. The species were Paecilomyces farinosus, Beauveria bassiana, Verticillium spp. and Penicillium pactum. Sensitive species were found among Mortierella, Oidiodendron and Penicillium. usually rare in polluted sites. Little evidence for adaptation to Cu was found among isolates with short or long history of pollution.
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| 15. |
- Back, C, et al.
(författare)
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High-dosage treatment of a Quebec stream with Bacillus thuringiensis serovar. israelensis : efficacy against black fly larvae (Diptera, Simuliidae) and impact on nontarget insects
- 1985
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Ingår i: Canadian Entomologist. - : Cambridge University Press. - 0008-347X .- 1918-3240. ; 117:12, s. 1523-1534
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Tidskriftsartikel (refereegranskat)abstract
- A typical lake outlet of the Canadian Shield was treated for 15 min with a high dose (5.28 g/L s−1 of discharge) of Teknar®, a commercial formulation of Bacillus thuringiensis serovar. israelensis. Efficacy on Simuliidae larvae and impact on non-target aquatic insects of this stream were monitored using drift nets, counting plates, and artificial turf substrates along a 1000-m section downstream of the site of application. Compared with a 4-day pre-treatment average for 12-h sampling periods, drift of Simuliidae increased from 64 to 92 ×, with shorter peaks of 133–184 ×, 2–6 h after treatment. There was no evident drift increase in larvae of Ephemeroptera, Plecoptera, Trichoptera, Chironomidae, or dipterous pupae, but larvae of Blephariceridae (Diptera) were severely affected as their drift was increased by up to 50 × and remained high for 3 days. After 30 h the mortality of Simuliidae on counting plates ranged from 95 to 82% in the first 300 m, with detachment rates of 78.5–46.5%. Densities of non-target insect larvae were not reduced on the artificial substrates, except for 2 genera of Chironomidae (Eukiefferella and Polypedilum) which were reduced 26 to 39% of their original density. Drifting larvae of 1 chironomid genus (Phaenopsectra) also showed symptoms of toxemia by B.t.i. The main impact of the treatment was thus seen in 2 Nematocera families (Chironomidae and Blephariceridae) which were mainly exposed to B.t.i. sedimented on the bottom of the stream or attached to periphyton growing on rocks.
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| 16. |
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| 17. |
- Backéus, Ingvar
(författare)
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I västerled till Shetland
- 1983
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Ingår i: Svensk Botanisk Tidskrift. - 0039-646X. ; 77, s. 26-
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Recension (populärvet., debatt m.m.)
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| 18. |
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| 19. |
- Backéus, Ingvar
(författare)
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Myrar i Örebro län
- 1984
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Ingår i: Svensk Botanisk Tidskrift. - 0039-646X. ; 78, s. 21-44
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Tidskriftsartikel (refereegranskat)
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| 20. |
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