Abundance, distribution, and territory areas of rock-dwelling Lake Tanganyika cichlid fish species

Hydrobiologia (Impact Factor: 2.21). 12/2008; 615(1):57-68. DOI: 10.1007/978-1-4020-9582-5_5

ABSTRACT Lake Tanganyika, the second-oldest and second-deepest lake in the world, harbors an impres-sive cichlid fish fauna counting about 250 endemic species that are characterized by a great level of ecological, morphological, and behavioral specializa-tion. This study describes and compares cichlid fish communities at two rocky shores with differential human impact in the south of Lake Tanganyika. Species inventories and depth-dependent abundances were elaborated. About 41 and 46 sympatric cichlid species were recorded in the two study sites, respec-tively. Variabilichromis moorii was the most abundant species (29–60% of total number of fishes), followed by Aulonocranus dewindti (3–19%), Tro-pheus moorii (12%), Ophthalmotilapia ventralis (4–10%), Eretmodus cyanostictus (6–11%), and Cyathopharynx furcifer (0.01–9%). All other species had abundances below 5%. It further emerged that large cichlids such as Petrochromis species, Cyatho-pharynx furcifer, and Lobochilotes labiatus were very rare at one location, with frequencies of 0.55% or less. Territorial sizes of three particularly abundant species, Variabilichromis moorii, Aulonocranus dew-indti, and Tropheus moorii, were assessed by behavioral observations. We distinguished between territorial core areas and total defended area, yielding average core areas between 0.4 (V. moorii) and 1.6 m 2 (T. moorii), and total defended areas averag-ing for each species between 1.6 (V. moorii) and 5.0 m 2 (A. dewindti) with no significant differences between the two study sites. The data on individual densities are also relevant for evolutionary studies, in that they allow more accurate calculations of effec-tive population sizes.

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Available from: Stephan Koblmüller, Aug 07, 2015
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    • "After spawning, females abandon their mate for maternal mouthbrooding (Yanagisawa and Nishida 1991). Territory quality influences male mating success (Yanagisawa and Nishida 1991; Hermann et al. 2015), and competition for territories ensues from the high density of Tropheus in the rocky littoral of Lake Tanganyika (e.g., Sturmbauer et al. 2008). "
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    ABSTRACT: Assortative mating promotes reproductive isolation and allows allopatric specia-tion processes to continue in secondary contact. As mating patterns are determined by mate preferences and intrasexual competition, we investigated male–male competition and behavioral isolation in simulated secondary contact among allopatric populations. Three allopatric color morphs of the cichlid fish Tropheus were tested against each other. Dyadic male–male contests revealed dominance of red males over bluish and yellow-blotch males. Reproductive isolation in the presence of male–male competition was assessed from genetic parent-age in experimental ponds and was highly asymmetric among pairs of color morphs. Red females mated only with red males, whereas the other females performed variable degrees of heteromorphic mating. Discrepancies between mating patterns in ponds and female preferences in a competition-free, two-way choice paradigm suggested that the dominance of red males interfered with positive assortative mating of females of the subordinate morphs and provoked asymmet-ric hybridization. Between the nonred morphs, a significant excess of negative assortative mating by yellow-blotch females with bluish males did not coincide with asymmetric dominance among males. Hence, both negative assortative mating preferences and interference of male–male competition with positive assorta-tive preferences forestall premating isolation, the latter especially in environments unsupportive of competition-driven spatial segregation.
    Ecology and Evolution 04/2015; DOI:10.1002/ece3.1372 · 1.66 Impact Factor
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    • "Males and females actively defend separate feeding territories in the shallow littoral of Lake Tanganyika, East Africa, and browse on epilithic algae. The densely packed, contiguous territories range in size from 0.25 to 4 m 2 (Takamura 1984; Sturmbauer et al. 2008), and observations of frequent replacements and territory expansions upon removal of territory holders (Yanagisawa and Nishida 1991) suggest strong intraspecific competition (Grant 1997). Tropheus are maternal mouthbrooders. "
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    ABSTRACT: Non-sexual social selection can underlie the evolution of sexually monomorphic phenotypes. A causal relationship between territorial competition and sexual monomorphism predicts that male and female competitors should employ similar contest behavior and that contest outcome should depend on the same traits in males and females. We test this prediction in a sexually monomorphic cichlid fish of the genus Tropheus, in which males and females defend individual feeding territories. Lineages basal to Tropheus are sexually dimorphic and have non-territorial females, suggesting that a switch to female territoriality and loss of sexual dimorphism occurred in the Tropheus lineage. We compare rates of agonistic behavior and the effects of body size asymmetries on competitive success between male-male and female-female contests in an experimental setup. Body size asymmetry had the same effect in male and female contests, being negatively correlated with contest duration and positively correlated with the probability of winning. Male and female winners employed the same rates of frontal and lateral displays as well as charges against their opponents. Contest duration was longer in females. In tied contests, females displayed more than males. Our data suggest that intraspecific contest competition for territories selects for large body size in both sexes and support a link between the evolution of female territoriality and the loss of sexual size dimorphism in Tropheus. Electronic supplementary material The online version of this article (doi:10.1007/s00265-014-1870-0) contains supplementary material, which is available to authorized users.
    Behavioral Ecology and Sociobiology 04/2015; 69(4). DOI:10.1007/s00265-014-1870-0 · 3.05 Impact Factor
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    • "Obviously, the most relevant assessment of the variance in reproductive success would be obtained from parentage reconstructions in natural populations (e.g., Weatherhead & Boag, 1997; Coltman et al., 1999; Friedl & Klump, 1999; Serbezov et al., 2010), with the caveat that this approach depends on the comprehensive sampling of juveniles and potential parents. The large census size of Tropheus (Sturmbauer et al., 2008) impedes the identification of closely related individuals in a randomly drawn sample; for example, the probability of an individual's parent being included in population samples of 200–300 Tropheus was estimated to be only 1–7%, and only 4–10 individuals were assigned a parent in these samples (Koch et al., 2008). The presented experiment complements a simulation of Tropheus reproduction, which suggested that pair bonding and monogamous spawning do not necessarily curb the potential for sexual selection, if concordant female preferences provide for variance in male reproductive success (Sefc, 2008). "
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    ABSTRACT: Discriminating female mate preferences enhance the variance in reproductive success among males of a population and create a potential for sexual selection, which can account for trait evolution and diversification. Fish color patterns are among the prime targets of mate choice-driven sexual selection. Populations of the cichlid Tropheus from Lake Tanganyika display remarkable geographic color pattern variation, but the role of female choice in their rapid and rich phenotypic diversification is unclear. Males and females establish a pair bond prior to spawning monogamously, but as brood care is strictly maternal, female investment in reproduction is high and the operational sex ratio is male-biased. Therefore, variance in male reproductive success can accrue if individual males succeed repeatedly in securing a mate. To test this prediction in the red colored Tropheus moorii "Chimba", four pairs of males were presented to a series of females and female mate preferences were inferred from pairwise interactions. There was a significant difference in mating success between the males of each pair (P < 0.001 over all trials), as-with one exception-females shared preferences for the same males. Male courtship activity was strongly correlated with female choice. Our experiment suggests that female choice contributes to the variance in male reproductive success in the tested population.
    Hydrobiologia 02/2012; 682(1). DOI:10.1007/s10750-011-0766-5 · 2.21 Impact Factor
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