Research interest: evolutionary behavioural ecology, part= ner choice, sexual selection, communication, and acoustic communication= . I have main= ly studied cod (Gadus morhua) and sticklebacks (Gasterosteus = aculeatus).
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| =20=0D=0A During the last years I have= studied spawning behaviour of cod. Cod are described as a promiscous g= roup spawner in textbooks and papers until lately. This is strange from= an evolutionary point of view, and in a review of published papers we = suggested that the cod mating system is best described as a \\\\\\\"lek= \\\\\\\" mating system. This is based on significantly skewed sex ratio= s - mainly towards males - from catches at spawning grounds, recordings= of a hushed hubbub of sound from the spawning grounds during spawning,= large variation between calls from fish kept in tanks, significantly l= arger grunting muscles of males than females (a secondary sexual charac= teristic?), and descriptions of an elaborate courtship and dance behavi= our prior to the shed of gametes. In an experiment where 9 males and 8 = females were crossed in all (72) different combinations and their offsp= ring reared and monitored 19 days post-fertilisation, the results revea= led a potential for 74 percent higher fitness by active partner choice = compared to random mating. =0D=0A Two cod groups which, according to population geneticists appearently do = not interbreed, both spawn at the same spawning grounds off the Lofoten= Islands simultaneously. We suspected that the calls from two cod group= s and perhaps dance, were prezygotic behavioural mechanisms preventing = interbreeding between the two groups. However, from analysis of grunts = from cod in tanks, we have not been able to tell apart sounds from the = two cod groups. =0D=0AFemale sticklebacks from sev= eral local populations have red carotenoid-based ornamented pelvic spin= es. I tested whether heavily ornamented females are preferred as mates = by males. The result, however, showed that males courted drab females m= ore than red females. Another study revealed a trade-off between the an= ti-oxidant carotenoids in spines and gonads of the females. Males choos= ing red coloured females will fertilise eggs with small amounts of caro= tenoids and seem not to gain anything regarding their mate\\\\\\\'s phe= notypic quality that could result in offspring of improved quality. Thi= s interpretation favours the non-adaptive hypotheses to explain the evo= lution of red spines in females sticklebacks. =0D=0A
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