Limited pre- and post- zygotic reproductive isolation barriers in two sympatric killifish species

0337027 - ÚBO 2010 DE eng A - Abstrakt
Polačik, Matej - Reichard, Martin
Limited pre- and post- zygotic reproductive isolation barriers in two sympatric killifish species.
International Conference on Evolutionary Ecology of Fishes Diversification, Adaptation and Speciation. Berlin: Leibnitz-Institute of Freshwater Ecology and Inland Fisheries, 2009. s. 124.
[International Conference on Evolutionary Ecology of Fishes Diversification, Adaptation and Speciation. 23.11.2009-25.11.2009, Berlin]
Grant CEP: GA ČR GA206/09/0815
Výzkumný záměr: CEZ:AV0Z60930519
Klíčová slova: fish reproduction * killifish
Kód oboru RIV: EH - Ekologie - společenstva

Studies on interspecific pre- and post-zygotic reproductive barriers may provide useful insights into how speciation proceeds and how species remain separated. We examined reproductive isolation barriers between Nothobranchius furzeri and N. orthonotus, two sympatric and closely related African annual killifish species, under laboratory conditions. These two species commonly co-occur in small temporary pools and are characterized by multiple spawning every day throughout their adult lifespan, very similar ecology and morphology. Our experimental design involved recording of courtship and mating behaviour during conspecific and heterospecific spawning and collection of data on the number of eggs spawned, egg and embryo survival rate throughout their development and hatching success. The spawning trials were run with either short (24 h) or long (72 h) sexual abstinence of mating pairs to further test the role of mate availability on spawning decisions. Conspecific pairs spawned more readily than heterospecific pairs. However, N. orthonotus males attempted to mate with N. furzeri females at a rate close to mating attempts with a conspecific female. On the contrary, N. furzeri males showed only weak interest in N. orthonotus females. The behaviour of mating pairs was not different after both the short and long interspawning interval. Conspecific pairs produced more eggs than heterospecific pairs, demonstrating higher female willingness to spawn with conspecific males. Although egg and embryo survival rate and hatching success were higher in conspecific pairs, heterospecific mating still resulted in some viable offspring. Collectively, our results showed that pre- and post-zygotic reproductive isolation barriers between N. furzeri and N. orthonotus were limited under experimental conditions. Further, at least behavioural pre-zygotic barriers were asymmetrical, with male N. orthonotus successfully courting female N. furzeri at relatively high rate. We assume that in promiscuous species, with multiple spawning acts each day, selection on strong mate preferences may be relaxed, given that only a small portion of resources is allocated to each single spawning. Our next step is to look at prezygotic barriers under natural setting and to investigate F1 progeny and backcrosses. We further run genotyping of wild populations on microsatellite and mitochondrial markers which should enable us to see cases of introgression under natural conditions.
Trvalý link: http://hdl.handle.net/11104/0181118