Summary week 2 – Martine maandDevelopmental effects of visual environment on species-assortativemating preferences in Lake Victoria cichlid fishBram Spierings | 950620790080 | Frontiers in Biology | 18-01-18 IntroductionSpeciation is the formation of distinct specieswithin the course of evolution. Geographical changes, barries (allopatric) orsexual selection (sympatric) are examples of factors which are the drivingprocess behind speciation. Previous studies indicate that sympatric speciationcould be driven by heterogeneous environments when geographical obstacles aremissing. An example of sympatric speciation in a heterogeneous environment isthe sensory speciation in two species of Chichlids in Lake Victoria. Twoclosely related Chichlids, Pundamilianyererei and Pundamilia pundamilalive in the same lake but differ in preference of waterdepth, and thus lightintensity.
Both species behave as ‘real’ species when they are present in theirprefered habitat but hybridize in turbid habitat where. State of the artAlthough the aquatic ecosystem shows evidence invisial communication, reproductive isolation due to visual adaptation hasn’tbeen proved yet. Previous research to the effect of changing visual conditionson mate choice for killifish did not show a comprehensive result but suggesteda small effect of sensory development on color choice. This promissingsuggestion is why the link between visual system properties and visual matepreferences should be further investigated.Another study has found that p. nyererei expresses higher long-wavelength-sensitive visualpigment and is more sensitive to red colors compared to P. pundamila. Furthermore, the characteristics of male coloration,photic environment and female preferences are correlated with the visialsystems which the Chichlids prefer.
Botch Chichlids species and theircrossbreeds are used in this experiment. The Chichlids were reared undersimulated red colored deep- (turbid) and blue colored shallow (clear) waterconditions. Afterwards the preference of females for red or blue males underdifferent light settings was tested. Recent findings Female preference was significantly affected by therearing light conditions. Quiver and courtship behaviour for P.pundamila and P. nyerereiwas prefered by both deep and shallow reared females however P.
pundamila was more prefered byfemales which were reared in simulated shallow water habitat. The femaleChichlids which were reared in deep water habitat did not have a specificpreference for any of the male Chichlids species. Furthermore it turned out that the interactionbetween rearing light and female species for both lateral display and quiver issignificant. Thus, females do more frequently respond to males of the samespecies when brood in natural habitat circumstances.