scholarly journals Female preference for conspecific males based on olfactory cues in a Lake Malawi cichlid fish

2005 ◽  
Vol 1 (4) ◽  
pp. 411-414 ◽  
Author(s):  
Martin Plenderleith ◽  
Cock van Oosterhout ◽  
Rosanna L Robinson ◽  
George F Turner

Research on reproductive isolation in African cichlid fishes has largely focused on the role of nuptial colours, but other sensory modes may play an important role in mate choice. Here, we compare the relative importance of visual and olfactory cues in mate recognition by females of a Lake Malawi cichlid species. Female Pseudotropheus emmiltos were given a choice of spawning next to a conspecific male or a male of the closely-related sympatric Pseudotropheus fainzilberi . Significant preference for conspecific males only occurred when olfactory cues were present. This suggests that divergence of olfactory signals may have been an important influence on the explosive radiation of the East African species flock.

2019 ◽  
Vol 37 (4) ◽  
pp. 1100-1113 ◽  
Author(s):  
Hannes Svardal ◽  
Fu Xiang Quah ◽  
Milan Malinsky ◽  
Benjamin P Ngatunga ◽  
Eric A Miska ◽  
...  

Abstract The adaptive radiation of cichlid fishes in East African Lake Malawi encompasses over 500 species that are believed to have evolved within the last 800,000 years from a common founder population. It has been proposed that hybridization between ancestral lineages can provide the genetic raw material to fuel such exceptionally high diversification rates, and evidence for this has recently been presented for the Lake Victoria region cichlid superflock. Here, we report that Lake Malawi cichlid genomes also show evidence of hybridization between two lineages that split 3–4 Ma, today represented by Lake Victoria cichlids and the riverine Astatotilapia sp. “ruaha blue.” The two ancestries in Malawi cichlid genomes are present in large blocks of several kilobases, but there is little variation in this pattern between Malawi cichlid species, suggesting that the large-scale mosaic structure of the genomes was largely established prior to the radiation. Nevertheless, tens of thousands of polymorphic variants apparently derived from the hybridization are interspersed in the genomes. These loci show a striking excess of differentiation across ecological subgroups in the Lake Malawi cichlid assemblage, and parental alleles sort differentially into benthic and pelagic Malawi cichlid lineages, consistent with strong differential selection on these loci during species divergence. Furthermore, these loci are enriched for genes involved in immune response and vision, including opsin genes previously identified as important for speciation. Our results reinforce the role of ancestral hybridization in explosive diversification by demonstrating its significance in one of the largest recent vertebrate adaptive radiations.


2002 ◽  
Vol 51 (1) ◽  
pp. 113-135 ◽  
Author(s):  
Walter Salzburger ◽  
Axel Meyer ◽  
Sanja Baric ◽  
Erik Verheyen ◽  
Christian Sturmbauer

2015 ◽  
Vol 112 (51) ◽  
pp. 15568-15573 ◽  
Author(s):  
Robert P. Lyons ◽  
Christopher A. Scholz ◽  
Andrew S. Cohen ◽  
John W. King ◽  
Erik T. Brown ◽  
...  

The transport of moisture in the tropics is a critical process for the global energy budget and on geologic timescales, has markedly influenced continental landscapes, migratory pathways, and biological evolution. Here we present a continuous, first-of-its-kind 1.3-My record of continental hydroclimate and lake-level variability derived from drill core data from Lake Malawi, East Africa (9–15° S). Over the Quaternary, we observe dramatic shifts in effective moisture, resulting in large-scale changes in one of the world’s largest lakes and most diverse freshwater ecosystems. Results show evidence for 24 lake level drops of more than 200 m during the Late Quaternary, including 15 lowstands when water levels were more than 400 m lower than modern. A dramatic shift is observed at the Mid-Pleistocene Transition (MPT), consistent with far-field climate forcing, which separates vastly different hydroclimate regimes before and after ∼800,000 years ago. Before 800 ka, lake levels were lower, indicating a climate drier than today, and water levels changed frequently. Following the MPT high-amplitude lake level variations dominate the record. From 800 to 100 ka, a deep, often overfilled lake occupied the basin, indicating a wetter climate, but these highstands were interrupted by prolonged intervals of extreme drought. Periods of high lake level are observed during times of high eccentricity. The extreme hydroclimate variability exerted a profound influence on the Lake Malawi endemic cichlid fish species flock; the geographically extensive habitat reconfiguration provided novel ecological opportunities, enabling new populations to differentiate rapidly to distinct species.


2006 ◽  
Vol 23 (4) ◽  
pp. 828-837 ◽  
Author(s):  
Yong-Jin Won ◽  
Yong Wang ◽  
Arjun Sivasundar ◽  
Jeremy Raincrow ◽  
Jody Hey

2015 ◽  
Vol 2 (3) ◽  
pp. 140498 ◽  
Author(s):  
Britta S. Meyer ◽  
Adrian Indermaur ◽  
Xenia Ehrensperger ◽  
Bernd Egger ◽  
Gaspard Banyankimbona ◽  
...  

The species flocks of cichlid fishes in the East African Great Lakes are the largest vertebrate adaptive radiations in the world and illustrious textbook examples of convergent evolution between independent species assemblages. Although recent studies suggest some degrees of genetic exchange between riverine taxa and the lake faunas, not a single cichlid species is known from Lakes Tanganyika, Malawi and Victoria that is derived from the radiation associated with another of these lakes. Here, we report the discovery of a haplochromine cichlid species in Lake Tanganyika, which belongs genetically to the species flock of haplochromines of the Lake Victoria region. The new species colonized Lake Tanganyika only recently, suggesting that faunal exchange across watersheds and, hence, between isolated ichthyofaunas, is more common than previously thought.


2019 ◽  
Author(s):  
Hannes Svardal ◽  
Fu Xiang Quah ◽  
Milan Malinsky ◽  
Benjamin P Ngatunga ◽  
Eric A Miska ◽  
...  

AbstractThe adaptive radiation of cichlid fishes in East Afrian Lake Malawi encompasses over 500 species that are believed to have evolved within the last 800 thousand years from a common founder population. It has been proposed that hybridisation between ancestral lineages can provide the genetic raw material to fuel such exceptionally high diversification rates, and evidence for this has recently been presented for the Lake Victoria Region cichlid superflock. Here we report that Lake Malawi cichlid genomes also show evidence of hybridisation between two lineages that split 3-4 million years ago, today represented by Lake Victoria cichlids and the riverine Astatotilapia sp. ‘ruaha blue’. The two ancestries in Malawi cichlid genomes are present in large blocks of several kilobases, but there is little variation in this pattern between Malawi cichlid species, suggesting that the large-scale mosaic structure of the genomes was largely established prior to the radiation. Nevertheless, tens of thousands of polymorphic variants apparently derived from the hybridisation are interspersed in the genomes. These loci show a striking excess of differentiation across ecological subgroups in the Lake Malawi cichlid assemblage, and parental alleles sort differentially into benthic and pelagic Malawi cichlid lineages, consistent with strong differential selection on these loci during species divergence. Furthermore, these loci are enriched for genes involved in immune response and vision, including opsin genes previously identified as important for speciation. Our results reinforce the role of ancestral hybridisation in explosive diversification by demonstrating its significance in one of the largest recent vertebrate adaptive radiations.


2003 ◽  
Vol 53 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Daud Kassam ◽  
Kosaku Yamaoka ◽  
Aggrey Ambali ◽  
Dean Adams

AbstractTo appreciate better how cichlids segregate along the trophic, spatial and temporal dimensions, it is necessary to understand the cichlids' body design, and its role in resource partitioning. We investigated body shape variation, quantified using landmark-based geometric morphometrics, among cichlid species belonging to algal and zooplankton feeders coexisting along the rocky shores of Lake Malawi, in order to elucidate the adaptive significance of body shape. Significant differences were found within zooplankton feeders in which Copadichromis borleyi had a shorter gape, smaller eyes and shorter caudal peduncle relative to Ctenopharynx pictus and, within algal feeders, Labeotropheus fuelleborni had a shorter and inferior subterminal gape, and shorter head relative to Petrotilapia genalutea. Variation among species is discussed with reference to trophic and feeding microhabitat differentiation which enables us to appreciate the role of body shape in enhancing ecological separation, and thus leads to coexistence among cichlid species.


Author(s):  
Sabine Urban ◽  
Alexander Nater ◽  
Axel Meyer ◽  
Claudius F Kratochwil

Abstract The adaptive radiations of East African cichlid fish in the Great Lakes Victoria, Malawi, and Tanganyika are well known for their diversity and repeatedly evolved phenotypes. Convergent evolution of melanic horizontal stripes has been linked to a single locus harboring the gene agouti-related peptide 2 (agrp2). However, where and when the causal variants underlying this trait evolved and how they drove phenotypic divergence remained unknown. To test the alternative hypotheses of standing genetic variation versus de novo mutations (independently originating in each radiation), we searched for shared signals of genomic divergence at the agrp2 locus. Although we discovered similar signatures of differentiation at the locus level, the haplotypes associated with stripe patterns are surprisingly different. In Lake Malawi, the highest associated alleles are located within and close to the 5′ untranslated region of agrp2 and likely evolved through recent de novo mutations. In the younger Lake Victoria radiation, stripes are associated with two intronic regions overlapping with a previously reported cis-regulatory interval. The origin of these segregating haplotypes predates the Lake Victoria radiation because they are also found in more basal riverine and Lake Kivu species. This suggests that both segregating haplotypes were present as standing genetic variation at the onset of the Lake Victoria adaptive radiation with its more than 500 species and drove phenotypic divergence within the species flock. Therefore, both new (Lake Malawi) and ancient (Lake Victoria) allelic variation at the same locus fueled rapid and convergent phenotypic evolution.


Lake Malawi, the third largest lake in Africa, is several million years old. Lake levels have fluctuated to a considerable extent in the late Pleistocene. Although tectonism may have influenced earlier level changes, the more recent changes have been climatically controlled. Major recessions occurred in the period before 25000 years ago and 10740 ± 130 years ago, with further large falls between 1150 and 1250 A. D. and within the period 1500-1850. The 1500-1850 lake recession-refilling cycle is documented by using a variety of techniques. Sediment cores show an erosional hiatus stretching across the southern area of Lake Malawi down to water depths of at least 121 m. Diatoms sharply decline in abundance and diversity across this break, with Melosira nyassensis dominating in the post-erosion period. During the low stage, exposed littoral sands were reworked into aeolian dune-fields along windward shorelines. Oral histories reflect a group memory of this low period, which is supported by 14 C dated archaeological finds in beach ridges surrounding the lake. Dating by 210 Pb methods show that lacustrine sedimentation had resumed by about 1860. At this time, early explorers, such as Livingstone, were reporting evidence of rising lake levels. Hydrological modelling shows that the lake-level changes indicated are possible in the timespan available. Various permutations of rainfall and timescale are discussed, e. g. a drop of 110 m over 250 years would require rainfall at 50% of modern values. The changes in lake level imply longterm changes in climate; these are highly relevant in the field of drought-risk assessment. The species flock of rocky-shore dwelling Lake Malawi cichlids known as ‘Mbuna’ contains about 200 species in Malawi’s waters. Mitochondrial DNA differentiation shows that the flock as a whole is of extremely recent origin. Almost every rocky outcrop and island has a unique Mbuna fauna, with endemic colour forms and species. As many of these islands and outcrops were dry land within the last 200-300 years, the establishment of the faunas has taken place within that time. The evolution of distinct forms in such a brief timespan is discussed in relation to current ideas on allopatric speciation. The present diversity of the Malawi cichlid-species flock, and particularly the Mbuna, may be readily explained by the rapidity with which small founder populations can diverge from the parent population, as demonstrated by the present chronological evidence on changes in lake levels and by the Mbuna distribution data. The repeated recessions and refillings of the lake have provided numerous opportunities for the establishment of different founder populations and consequently different selection pressures, leading to further bouts of speciation.


2007 ◽  
Vol 3 (2) ◽  
pp. 134-136 ◽  
Author(s):  
Machteld N Verzijden ◽  
Carel ten Cate

The Lake Victoria ‘species flock’ of cichlids is puzzling because reproductive isolation often occurs in the absence of substantial ecological differences among species. Theory predicts that this cannot evolve with most genetic mechanisms for mate choice. We provide the first evidence that learning, in the form of sexual imprinting, helps maintain reproductive isolation among closely related cichlid species. Using a cross-fostering experiment, we show that young females develop a sexual preference for males of their foster mothers' species, even reversing species assortative mating preferences. We suggest that learning creates favourable conditions for reproductive isolation to evolve.


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