scholarly journals The underwater photic environment of Cape Maclear, Lake Malawi: comparison between rock- and sand-bottom habitats and implications for cichlid fish vision

2011 ◽  
Vol 214 (3) ◽  
pp. 487-500 ◽  
Author(s):  
S. Sabbah ◽  
S. M. Gray ◽  
E. S. Boss ◽  
J. M. Fraser ◽  
R. Zatha ◽  
...  
Keyword(s):  
Cichlid Fish ◽  
Lake Malawi ◽  
Fish Vision ◽  
Sand Bottom

scholarly journals Continuous 1.3-million-year record of East African hydroclimate, and implications for patterns of evolution and biodiversity

2015 ◽  
Vol 112 (51) ◽  
pp. 15568-15573 ◽  
Author(s):  
Robert P. Lyons ◽  
Christopher A. Scholz ◽  
Andrew S. Cohen ◽  
John W. King ◽  
Erik T. Brown ◽  
...  
Keyword(s):  
Lake Level ◽  
Large Scale ◽  
Late Quaternary ◽  
Cichlid Fish ◽  
Biological Evolution ◽  
Distinct Species ◽  
Lake Malawi ◽  
Freshwater Ecosystems ◽  
Water Levels ◽  
Species Flock

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.

scholarly journals Evolution of a cichlid fish in a Lake Malawi satellite lake

2007 ◽  
Vol 274 (1623) ◽  
pp. 2249-2257 ◽  
Author(s):  
Martin J Genner ◽  
Paul Nichols ◽  
Gary R Carvalho ◽  
Rosanna L Robinson ◽  
Paul W Shaw ◽  
...  
Keyword(s):  
Cichlid Fish ◽  
Lake Malawi

scholarly journals Assortative mating among Lake Malawi cichlid fish populations is not simply predictable from male nuptial colour

2009 ◽  
Vol 9 (1) ◽  
pp. 53 ◽  
Author(s):  
Jonatan Blais ◽  
Martin Plenderleith ◽  
Ciro Rico ◽  
Martin I Taylor ◽  
Ole Seehausen ◽  
...  
Keyword(s):  
Assortative Mating ◽  
Cichlid Fish ◽  
Lake Malawi ◽  
Fish Populations

scholarly journals Segregation of Species-Specific Male Attractiveness in F2 Hybrid Lake Malawi Cichlid Fish

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Ola Svensson ◽  
Bernd Egger ◽  
Boye Gricar ◽  
Katie Woodhouse ◽  
Cock van Oosterhout ◽  
...  
Keyword(s):  
Mate Choice ◽  
Reproductive Isolation ◽  
Genetic Model ◽  
Cichlid Fish ◽  
Lake Malawi ◽  
Paternity Analysis ◽  
Colour Pattern ◽  
Male Mating ◽  
Heritable Variation ◽  
Species Specific

Among the huge radiations of haplochromine cichlid fish in Lakes Malawi and Victoria, closely related species are often reproductively isolated via female mate choice although viable fertile hybrids can be produced when females are confined only with heterospecific males. We generated F2 hybrid males from a cross between a pair of closely related sympatric cichlid fish from Lake Malawi. Laboratory mate choice experiments using microsatellite paternity analysis demonstrated that F2 hybrid males differed significantly in their attractiveness to females of the two parental species, indicating heritable variation in traits involved in mate choice that may contribute to reproductive isolation between these species. We found no significant correlation between male mating success and any measurement of male colour pattern. A simple quantitative genetic model of reproductive isolation suggests that there may be as few as two chromosomal regions controlling species-specific attractiveness. We propose that adaptive radiation of Lake Malawi cichlids could be facilitated by the presence of genes with major effects on mate choice and reproductive isolation.

scholarly journals Heterospecific aggression differs predominately by species, rather than sex, in Lake Malawi cichlid fish

2019 ◽  
Author(s):  
Emily C. Moore ◽  
Reade B. Roberts
Keyword(s):  
Community Structure ◽  
Rapid Evolution ◽  
Cichlid Fish ◽  
Lake Malawi ◽  
Male Aggression ◽  
Males And Females ◽  
Potential Impact ◽  
Cortisol Levels ◽  
Species Specific ◽  
Heterospecific Aggression

ABSTRACTBecause of their striking diversity, Lake Malawi cichlid fish have been well studied for male aggression, particularly among dominant males of closely related sister species within the framework of mate-choice and speciation. However, aggression in females has been largely ignored, and variation in aggressive behaviors between more distantly-related taxa is not well understood despite its potential impact in a complex community structure. To better understand variation in patterns of aggression between species, we presented males and females from five species of Lake Malawi cichlid with a non-predator intruder and recorded all movement and aggressive acts. Additionally, we measured excreted cortisol levels the day after the intruder assay to evaluate one physiological aspect of stress response. We identified species-specific patterns in both specific aggressive acts, and overall level of aggression. Additionally, we found that sexual dimorphism in aggressive acts varies by species and act, where the species with the most aggressive males also has aggressive females. Additionally, cortisol levels vary by taxa, and are associated with restless behavior in the intruder assay, but not levels of aggression. These findings have bearing on understanding sex differences in aggression and their impact on community structure in this important model of rapid evolution.

scholarly journals Genomic Characterization of a B Chromosome in Lake Malawi Cichlid Fishes

2018 ◽  
Author(s):  
Frances Clark ◽  
Matthew Conte ◽  
Thomas Kocher
Keyword(s):  
Dna Sequence ◽  
Sequence Data ◽  
Cichlid Fish ◽  
B Chromosome ◽  
Lake Malawi ◽  
B Chromosomes ◽  
Sequence Coverage ◽  
Specific Sequence ◽  
Genomic Characterization ◽  
B Chromosome Evolution

B chromosomes (Bs) were discovered a century ago, and since then most studies have focused on describing their distribution and abundance using traditional cytogenetics. Only recently have attempts been made to understand their structure and evolution at the level of DNA sequence. Many questions regarding the origin, structure, function and evolution of B chromosomes remain unanswered. Here we identify B chromosome sequences from several species of cichlid fish from Lake Malawi by examining the ratios of DNA sequence coverage in individuals with and without B chromosomes. We examine the efficiency of this method, and compare results using both Illumina and PacBio sequence data. The B chromosome sequences detected in 13 individuals from 7 species were compared to assess the rates of sequence replacement. B-specific sequence common to at least 12 of the 13 datasets are identified as the “Core” B chromosome. The location of B sequence homologs throughout the genome provides further support for theories of B chromosome evolution. Finally, we identified candidate genes located on the B chromosome which may regulate the segregation and maintenance of the B chromosome.

scholarly journals Whole genome sequences of Malawi cichlids reveal multiple radiations interconnected by gene flow

2017 ◽  
Author(s):  
Milan Malinsky ◽  
Hannes Svardal ◽  
Alexandra M. Tyers ◽  
Eric A. Miska ◽  
Martin J. Genner ◽  
...  
Keyword(s):  
Gene Flow ◽  
Fish Species ◽  
Phylogenetic Analyses ◽  
Cichlid Fish ◽  
Sequence Divergence ◽  
Single Species ◽  
Lake Malawi ◽  
Genomic Diversity ◽  
Average Sequence Divergence ◽  
Deep Water Species

AbstractThe hundreds of cichlid fish species in Lake Malawi constitute the most extensive recent vertebrate adaptive radiation. Here we characterize its genomic diversity by sequencing 134 individuals covering 73 species across all major lineages. Average sequence divergence between species pairs is only 0.1-0.25%. These divergence values overlap diversity within species, with 82% of heterozygosity shared between species. Phylogenetic analyses suggest that diversification initially proceeded by serial branching from a generalistAstatotilapia-likeancestor. However, no single species tree adequately represents all species relationships, with evidence for substantial gene flow at multiple times. Common signatures of selection on visual and oxygen transport genes shared by distantly related deep water species point to both adaptive introgression and independent selection. These findings enhance our understanding of genomic processes underlying rapid species diversification, and provide a platform for future genetic analysis of the Malawi radiation.One Sentence Summary: The genomes of 73 cichlid fish species from Lake Malawi uncover evolutionary processes underlying a large adaptive evolutionary radiation.

A new species of Diplotaxodon (Cichliformes: Cichlidae) from Lake Malaŵi

Zootaxa ◽  
2021 ◽  
Vol 4903 (2) ◽  
pp. 275-284
Author(s):  
JAY R JR. STAUFFER ◽  
ADRIANUS F. KONINGS
Keyword(s):  
New Species ◽  
Principal Components Analysis ◽  
Principal Components ◽  
Cichlid Fish ◽  
Lake Malawi ◽  
Type Specimens ◽  
Snout Length ◽  
Haplochromine Cichlid ◽  
Components Analysis ◽  
A New Species

A species of haplochromine cichlid fish of the genus Diplotaxodon Trewavas, endemic to Lake Malaŵi is described: Diplotaxodon dentatus, new species. All eight type specimens were trawled together off Thumbi East Island in the Southeastern arm of the lake at 73 meters in 1985. They were initially identified as D. argenteus because the teeth on the oral jaws were fully exposed with a closed mouth. The shorter snout length of D. dentatus (26.6–29.2 % HL) clearly separates it from D. argenteus (31.7–34.2 % HL). A plot of a principal components analysis further supports the separation of D. dentatus from D. argenteus. 

Sign in / Sign up

Export Citation Format

Share Document