SwePub
Sök i SwePub databas

  Extended search

Träfflista för sökning "(AMNE:(NATURVETENSKAP) AMNE:(Biologi)) srt2:(1980-1994) srt2:(1985-1989)"

Search: (AMNE:(NATURVETENSKAP) AMNE:(Biologi)) srt2:(1980-1994) > (1985-1989)

  • Result 1-10 of 672
Sort/group result
   
EnumerationReferenceCoverFind
1.
  •  
2.
  •  
3.
  •  
4.
  •  
5.
  • Berglund, Anders, et al. (author)
  • Mate choice, fecundity and sexual dimorphism in two pipefish species (Syngnathidae)
  • 1986
  • In: Behavioral Ecology and Sociobiology. - 0340-5443 .- 1432-0762. ; 19:4, s. 301-307
  • Journal article (peer-reviewed)abstract
    • In order to understand the causes of sexual dimorphism, mate choice and size-related fecundity were studied in two pipefish species, Syngnathus typhle and Nerophis ophidion. Sexual dimorphism is more pronounced in N. ophidion; females are larger, have sexual colourings, and are more active during courtship. In S. typhle the sexes are alike in all these respects. Males brood their offspring in both species. In N. ophidion fecundity was positively correlated with both body size and the amount of sexual colouring in females. In males no correlation between body size and fecundity, or between body size and embryo size existed. Predictably, in mate choice experiments with equal-sized females, males chose females with more extensive sexual colourings. We explain sexual dimorphism in this species as a consequence of both natural selection (fecundity increases with size in females but not in males) and sexual selection (males prefer larger females). We argue that sexual size dimorphism did not evolve by selection minimizing overlap in food niches between the sexes, because food production is high in the Zostera beds where the fishes live, and no size dimorphism was found in the sympatrically occurring S. typhle. Furthermore, in N. ophidion dimorphism is not greater in a particular mouth character than in overall body size. In S. typhle egg size and the average number of eggs transferred per spawning were positively correlated with female body size. Apparently more energy per offspring was provided by larger males than by smaller males, and larger males also carried more offspring. As predicted, large mates were preferred by both sexes in mate choice experiments. This is explicable in terms of both natural selection (fecundity increases with size in both sexes) and sexual selection (both sexes prefer large mates). As a consequence of selection acting in the same direction in both sexes, sexual dimorphism is absent in S. typhle.
  •  
6.
  •  
7.
  • Berglund, Anders, et al. (author)
  • Reproductive success of females limited by males in two pipefish species
  • 1989
  • In: American Naturalist. - 0003-0147 .- 1537-5323. ; 133:4, s. 506-516
  • Journal article (peer-reviewed)abstract
    • We investigate whether males limit the reproductive success of females in the two pipefish species Syngnathus typhle and Nerophis ophidion. Syngnathus typhle is sexually monomorphic, and courtship behavior does not differ between the sexes. In N. ophidion, on the contrary, females are larger, more colorful, and more active during courtship, possessing appearance-enlarging skin folds. In both species, males brood the offspring on their bodies, one internally and one externally. Males do not invest more energy in reproduction than do females, and in the sexually dimorphic species, males invest even less than females do. Natural sex ratios are equal in both species. Experimentally, we provided each female with an excess of males (i.e., three), in order to measure a female's maximal reproductive rate, and found that females of both species produced more eggs, or produced them at a faster rate, than naturally available males could care for. Within the time span of one male pregnancy, S. typhle females filled an average of 1.9 males and N. ophidion an average of 1.8 males; both numbers are significantly more than one (which is the average mate availability in natural populations). Measured in another way, during one male pregnancy, S. typhle and N. ophidion females both produced 41% more eggs than needed to fill a male, significantly more than no egg surplus in both species. Therefore, brood space and the rate of embryonic development limit female reproduction in these species. There was no significant difference between the species, however. Syngnathus typhle males might be expected to be less limiting than N. ophidion males, but sexual size dimorphism may be absent in S. typhle because, by contrast with N. ophidion, larger males enjoy greater reproductive success. Directional selection for increased male size may decrease sexual size dimorphism in S. typhle. At any rate, the limitation of the reproductive success of one sex by the other seems to be a necessary but not sufficient prerequisite for the evolution of sexual dimorphism and "sex roles."
  •  
8.
  •  
9.
  •  
10.
  •  
Skapa referenser, mejla, bekava och länka
  • Result 1-10 of 672
Type of publication
journal article (458)
doctoral thesis (118)
editorial collection (35)
book chapter (26)
conference paper (10)
book (9)
show more...
reports (8)
editorial proceedings (3)
other publication (3)
research review (2)
show less...
Type of content
peer-reviewed (465)
other academic/artistic (196)
pop. science, debate, etc. (9)
Author/Editor
Karlsson, Thomas (30)
Nordén, Bengt, 1945 (25)
Löfstedt, Christer (20)
Granéli, Edna (18)
Kärnefelt, Ingvar (18)
Hagström, Åke (17)
show more...
Larsson, Per (16)
Brodelius, Peter (16)
Hakman, Inger (16)
Söderström, Bengt (15)
Werdelin, Lars (14)
Hederstedt, Lars (13)
Björn, Lars Olof (13)
Elofsson, Rolf (12)
Rydin, Håkan (12)
Larsson, Per-Olof (10)
Nilsson, Jan Åke (9)
Smith, Henrik G. (9)
Dircksen, Heinrich, ... (9)
Rydström, J. (9)
Anderbrant, Olle (9)
Löfqvist, Jan (9)
Persson, Bengt L. (9)
Ekelund, Nils, 1956- (8)
Larsson, Christer (7)
Berglund, Anders (7)
Bååth, Erland (7)
HOGLUND, J (7)
Kanje, Martin (7)
Mosbach, Klaus (7)
Keller, Rainer (7)
Dave, Göran, 1945 (6)
Björklund, Mats (6)
Tunlid, Anders (6)
Ekström, Per (6)
Hansson, Bill S. (6)
Tiselius, Peter, 195 ... (6)
Tunlid, A. (6)
Ekman, Pia (6)
DePierre, J. W. (6)
Grubb, Anders (5)
Kjellbom, Per (5)
Okla, Lennart (5)
Angerbjörn, Anders (5)
Kubista, Mikael, 196 ... (5)
Rosenqvist, Gunilla (5)
Borgegård, S.-O. (5)
Edler, L. (5)
Eriksson, Magdalena, ... (5)
Fowke, L C (5)
show less...
University
Lund University (199)
Stockholm University (122)
Uppsala University (108)
Linnaeus University (102)
Chalmers University of Technology (32)
University of Gothenburg (28)
show more...
Umeå University (17)
Swedish Museum of Natural History (17)
Kristianstad University College (11)
Karlstad University (11)
Mid Sweden University (10)
Örebro University (8)
Malmö University (6)
Swedish Environmental Protection Agency (6)
Royal Institute of Technology (5)
Linköping University (4)
Halmstad University (3)
Jönköping University (3)
Södertörn University (2)
Swedish National Heritage Board (2)
Luleå University of Technology (1)
University of Borås (1)
show less...
Language
English (609)
Swedish (58)
Russian (4)
Danish (1)
Research subject (UKÄ/SCB)
Natural sciences (672)
Medical and Health Sciences (11)
Engineering and Technology (8)
Agricultural Sciences (4)
Social Sciences (2)
Humanities (2)

Year

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Close

Copy and save the link in order to return to this view