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| 2. |
- Göransson, Görgen, et al.
(author)
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Male characteristics, viability, and harem size in a wild population of pheasants.
- 1990
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In: Animal Behaviour. - 0003-3472 .- 1095-8282. ; 40:1, s. 89-104
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Journal article (peer-reviewed)abstract
- A population of pheasants was studied for 4 years in southern Sweden to determine how sexual selection operates among males. Morphological characters, viability, dominance, territory quality, date of territorial establishment, harem size and reproductive success of males were measured; 81 males and 101 females were radio-tracked. The spur length of males was the most important predictor of harem size. Phenotypic condition and viability were significantly related to spur length, the best single predictor of the reproductive success of males. These are the first data to show that a sexually selected male character correlates significantly with male viability. The results support models suggesting that viability-based processes can contribute to the evolution of mate choice and secondary sexual characters.
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| 3. |
- Regnell, Olof, et al.
(author)
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Effects of anoxia and sulfide on concentrations of total and methyl mercury in sediment and water in two Hg-polluted lakes
- 2001
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In: Canadian Journal of Fisheries and Aquatic Sciences. - 1205-7533. ; 58:3, s. 506-517
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Journal article (peer-reviewed)abstract
- Between May and December 1996, monthly samples of surface sediment (0-1 cm), settling matter, and water were taken at a shallow site and a deep site in each of two consecutive Hg-polluted riverine lakes. In the upper lake, the sediment was polluted also with cellulose fiber. Both hypolimnia turned anoxic, but sulfide was detected only in the upper lake. When sulfide appeared, hypolimnetic methyl mercury (MeHg) increased and reached 47 pM (9.4 ng.L-1), whereas MeHg in the sediment below decreased. The increase in hypolimnetic inorganic Hg (IHg = total Hg - MeHg), which reached a peak of 40 pM (8.0 ng.L-1), was slower, possibly because mobilized IHg was methylated. In the lower lake, hypolimnetic MeHg and IHg increased less dramatically during summer stratification, reaching only 5 and 24 pM (1.0 and 4.8 ng.L-1), respectively. There was no detectable concomitant decrease in sediment MeHg. In both lakes, MeHg appeared to increase simultaneously with total Fe and Mn in the hypolimnion, as did IHg in the lower lake. Our observations suggest that the presence of hydrous ferric and manganese oxides decreased the mobility of Hg in both lakes but increased MeHg production in the upper lake.
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| 4. |
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| 5. |
- von Schantz, Torbjörn, et al.
(author)
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Female choice - Reply
- 1989
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 339:6224, s. 432-433
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Journal article (peer-reviewed)
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| 6. |
- von Schantz, Torbjörn, et al.
(author)
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Female choice selects for a viability-based male trait in pheasants
- 1989
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 337, s. 166-169
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Journal article (peer-reviewed)abstract
- Recent theory on sexual selection1–4 suggests that females in species without paternal care choose mates by their secondary sexual characters because these indicate genotypic quality which will be transmitted to the offspring. These ideas are not yet empiri-cally supported as data quantifying the relationship between female mate choice and female reproductive success are lacking. Only in one case, in Colias butterflies, has it been demonstrated unequivo-cally that females choose 'good genotypes' as mates5 and there is only one study, on Drosophila, demonstrating that mate choice increases one component of offspring fitness6. Spur length of male pheasants (Phasianus colchicus) correlates with various fitness-related properties7. We here present the first experimental field data showing that female pheasants select mates on the basis of male spur length and that female mate choice correlates with female reproductive success.
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