Specifically, we tested the hypotheses that: (i) local populations are genetically differentiated, (ii) local populations differ in jaw morphology, dentition and standard length (SL), and (iii) variation in size is correlated with variation in trophic morphology.3. the extent of genetic, body size and trophic variation within and between populations of M. We speculated that body size and trophic morphology of M. It inhabits isolated rocky reefs among which community structure, resource availability and gene pools are likely to differ. The cichlid fish Metriaclima zebra, common in Lake Malawi, feeds by filtering plankton from the water and by brushing items from sediment covered substrata. These results suggest an additive mode of action of the alleles responsible for these phenotypes. For every character, hybrid progeny are statistically different from both parental species. The same series of measurements was made on hybrids between Labeotropheus and Metriaclima. We find many aspects of shape change that relate directly to the functional design of the cichlid head. We used the thin‐plate spline method to quantify morphological differences, which allowed us to relate our results to the functional biology of the species. In addition, we performed the same analysis on the neurocranium, an element closely associated with the oral jaws. We analyzed each of the four skeletal elements that make up the oral jaws: the dentary, articular, premaxilla, and maxilla. feeds in the water column with a “sucking” mode. Labeotropheus fuelleborni forages along the substrate with a “biting” mode of feeding, while Metriaclima zebra. To better understand the adaptive evolution of this trait, we performed a morphological analysis of the jaws of two closely related species from Lake Malawi that have very different modes of feeding. Cuckoo catfish and mouthbrooding cichlids provide a model system for testing brood parasitism in a laboratory setting.Įast African cichlid fishes have evolved a stunning array of oral jaw morphologies. Parasitism rates and number of catfish per brood were the highest in the albino morphotype suggesting that the higher levels of parasitism may be related to lower aggressive behavior, lower visual acuity, or captive influence. We also analyzed the parasitism rate of the albino morph of Metriaclima zebra, a domestic strain. horei parasitism frequency and number of cuckoo catfish per brood. Our results are comparable to findings from the field for C. The number of catfish eggs per parasitized brood was similar between C. horei may be due to differences in the mating ritual, oviposition (e.g., long periods of pseudo-spawning before actual oviposition), and behavioral adaptations (e.g., increased aggression towards the cuckoo catfish). horei was parasitized significantly less (17%) than the allopatric species Haplochromis latifasciatus, Haplochromis nubilus, and Metriaclima estherae (combined parasitism rate of 28%). Here we examine the frequency of parasitism by the cuckoo catfish of Ctenochromis horei from Lake Tanganyika and three species from Lake Malawi and the greater Lake Victorian system in a laboratory setting. The cuckoo catfish parasitizes Tanganyikan mouthbrooding cichlids, and under captive conditions, will also parasitize cichlids from other Rift Valley lakes. The only known non-avian vertebrate obligate brood parasite is the cuckoo catfish (Synodontis multipunctatus), a Lake Tanganyikan endemic.
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