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Göteborgs universitets publikationer

Sexual dimorphism in Bosmina: The role of morphology, drag, and swimming

Författare och institution:
Hans Lord (Zoologiska institutionen); Ragnar Lagergren (Zoologiska institutionen); Jan-Erik Svensson (-); Nils Lundqvist (Zoologiska institutionen)
Publicerad i:
Ecology, 87 ( 3 ) s. 788-795
Artikel, refereegranskad vetenskaplig
Sammanfattning (abstract):
Some Bosmina water flea species develop morphological antipredatory defenses, such as long antennules and a high carapace, but in Bosmina (Eubosmina) coregoni gibbera these traits are larger and more variable in females than in males. Here we propose that this sexual dimorphism derives from differential costs of hydrodynamic drag and selection for mobility in males. We tested this hypothesis by estimating drag of several Bosmina morphologies by using scale models sinking in glycerin of different concentrations and viscosities. Body forms included males, Sexual and asexual females of B. c. gibbera, and males and asexual females of Bosmina (Eubosmina) longispina, a taxon with less variable body shape. For a given body length or body volume, male models had lower drag than models of sexual and asexual females, Suggesting that males call swim 14-28% faster with the same energy consumption. Consistent with this conclusion, video recordings showed that males of B. c. gibbera advanced 55-73% farther than females in each swimming stroke. We Conclude that hydrodynamic drag may have significant implications for swimming and evolution of sexual dimorphism in water fleas, and we suggest that males lack the defensive Structures of females of B. c. gibbera (e.g.. high carapaces) because Competition over mates favors low drag.
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
Biologiska vetenskaper
bosmina coregoni gibbera, bosmina longispina, drag, hydrodynamic model, morphology, sexual dimorphism, swimming speed, zooplankton, predatory copepods, zooplankton, cladocera, leptodora, defenses, plankton, shape, size, prey
Postens nummer:
Posten skapad:
2007-05-28 13:36
Posten ändrad:
2007-09-06 09:14

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