Líffræðifélag Íslands
Líffræðiráðstefnan 2015
Erindi/veggspjald / Talk/poster V53
Hrefna Sigurjónsdóttir 1, Kalina H. Kapralova 2
"1 University of Iceland-School of Education; 2 University of Iceland-School of Engineering and Natural Sciences"
Kynnir / Presenter: Hrefna Sigurjónsdóttir
Tengiliður / Corresponding author: Hrefna Sigurjónsdóttir (hrefnas@hi.is)
Arctic charr in Thingvallavatn represent an extreme case of intralacustrine diversity with four morphs inhabiting the lake. Two of the morphs, a planktivorous (PL) and a piscivorous (PI) charr, are limnetic and have pointed snouts and evenly protruding jaws, while the small (SB) and a large benthic (LB) have blunt snouts, short lower jaws and relatively large pectoral fins. These morphs differ greatly in morphology, life history characteristics and ecology, as reflected in different habitat use, diet and endoparasite fauna. They all spawn in the stony littoral habitat, but the timing of spawning and the level of synchronization differ among the morphs. Opportunities for interbreeding among morphs exist, both between LB and SB on one hand and between the two smallest and most abundant morphs (PL and SB) on the other hand. Yet, a recent study, using microsatellite markers revealed subtle but significant genetic differentiation between PL, SB and LB and further coalescent simulations indicated a scenario of early evolution of reproductive isolation followed by slow divergence by drift with restricted gene flow. In situ observations of spawning behaviour have only been performed for LB. A case where agonistic behaviour of both male and female LB charr towards one SB male during spawning activities was witnessed by divers in the lake in 1986 as can be seen in the film Reproductive behaviour of arctic charr in lake Thingvallavatn. Here we report on a planned research in the summers and autumns of 2015-2016, which aims to film SB, PL and PI charr at the spawning grounds and test the hypothesis that reproductive isolation between the Thingvallavatn morphs is partly due to differences in the exact timing (i.e. time of the day), precise spawning location and/or behavior such as female choice and agonistic behaviour.