Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2019

Erindi/veggspjald / Talk/poster E2

Adaptive divergence in head morphology in Arctic charr (Salvelinus alpinus) from Thingvallavatn

Höfundar / Authors: Lieke Ponsioen (1), Quentin Horta-Lacueva (1), Sigurður S. Snorrason (1), Kalina H. Kapralova (1)

Starfsvettvangur / Affiliations: 1. University of Iceland

Kynnir / Presenter: Lieke Ponsioen

Arctic charr colonised lake Thingvallavatn after the end of the last Ice Age around 10,000 years ago. Since then the Arctic charr have diverged into four distinct morphs along benthic and limnetic ecological axes. The ecological differences are reflected in differences in head morphology, life history characteristics, behaviour and ontogeny. In order to test if differences in head morphology have a genetic basis and if they are established before the onset of exogenous feeding, the progeny of two contrasting morphs, the planktivorous (PL) and small benthic (SB) and their reciprocal crosses were reared in a common garden experiment. A total of 1047 individuals were sampled before the onset of first feeding, stained in Alcian blue for cartilage and Alizarin red for bones and photographed. Head morphology and size were evaluated using geometric morphometrics. Preliminary results indicate that pure morph progeny differ in shape and these differences are not due to size only. The shape distribution of hybrid progeny was intermediate to that of the two pure morphs but skewed towards the maternal morph. Our results indicate that the differences in head morphology between PL- and SB-charr are genetically based and therefore adaptive. The intermediate craniofacial phenotypes observed in hybrids may be sub-optimal and thus lead to lower fitness. Our study highlights the importance of development in adaptive divergence and speciation.