scholarly journals Alternative Reproductive Tactics in the Shell-Brooding Lake Tanganyika Cichlid Neolamprologus brevis

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Kazutaka Ota ◽  
Mitsuto Aibara ◽  
Masaya Morita ◽  
Satoshi Awata ◽  
Michio Hori ◽  
...  
Keyword(s):  
Lake Tanganyika ◽  
Field Studies ◽  
Alternative Reproductive Tactics ◽  
Reproductive Tactics ◽  
Sandy Bottom ◽  
Cichlid Species ◽  
Somatic Condition ◽  
Males And Females ◽  
Rocky Habitats ◽  
Sexually Mature

Alternative reproductive tactics (ARTs) are found in several Lake Tanganyika shell-brooding cichlids. Field studies were conducted in the Wonzye population to examine reproductive ecology and ARTs in the Lake Tanganyika shell-brooding cichlid Neolamprologus brevis. We discovered that this fish occurred in both rocky- and sandy-bottom habitats, but in rocky habitats, brood-caring females exclusively occurred in shell-patches that another cichlid species created. All N. brevis of both sexes in the patches were sexually mature, whereas immature males and females with unripe eggs were found frequently in sandy-bottom habitats. Males in sandy-bottom habitats were smaller, but fed more frequently and were in better somatic condition than males in the patches. Similar tendency was found in females. This indicates that N. brevis uses different habitats depending on the stage of its life history, with migration from sandy-bottom habitats to the shell-patches for reproduction. Males in the patches exhibited different behavior patterns: floating above the patches and lying in the patches. The former was larger, more aggressive, and invested less in gonads (relative to body size) than the latter. These results accord with those of other shell-brooding Lake Tanganyika cichlids with ARTs, and they therefore suggest the presence of ARTs in N. brevis.

scholarly journals Mating and Parental Care in Lake Tanganyika's Cichlids

2011 ◽  
Vol 2011 ◽  
pp. 1-20 ◽  
Author(s):  
Kristina M. Sefc
Keyword(s):  
Parental Care ◽  
Cooperative Breeding ◽  
Mating Systems ◽  
Lake Tanganyika ◽  
Species Level ◽  
Reproductive Tactics ◽  
Reproductive Behaviors ◽  
Cichlid Species ◽  
Care Patterns ◽  
Selection Intensities

Cichlid fishes of Lake Tanganyika display a variety of mating and parental care behaviors, including polygamous and monogamous mouthbrooding and substrate breeding, cooperative breeding, as well as various alternative reproductive tactics such as sneaking and piracy. Moreover, reproductive behaviors sometimes vary within species both in space and in time. Here, I survey reports on mating and parenting behaviors of Lake Tanganyika cichlid species and address the evolution of mating and parental care patterns and sexual dimorphism. Notes on measures of sexual selection intensity and the difficulties of defining mating systems and estimating selection intensities at species level conclude the essay.

scholarly journals Weather stochasticity and alternative reproductive tactics in Northern chamois, Rupicapra rupicapra

2020 ◽  
Vol 130 (2) ◽  
pp. 359-364
Author(s):  
Luca Corlatti ◽  
Bruno Bassano ◽  
Sandro Lovari
Keyword(s):  
Snow Depth ◽  
Weather Conditions ◽  
External Factors ◽  
Alternative Reproductive Tactics ◽  
Reproductive Tactics ◽  
Internal Factors ◽  
Rupicapra Rupicapra ◽  
Selective Pressures ◽  
Mating Opportunities ◽  
Males And Females

Abstract In polygynous ungulates, male breeding success is often achieved through alternative reproductive tactics (ARTs). The maintenance of ARTs in this taxon is largely explained by condition-dependent selection, a decision rule in which individuals switch their breeding behaviour on the basis of internal factors such as ageing (status-dependent selection), or external factors such as weather conditions during the rut (environment-dependent selection). In some species, however, ARTs are fixed during the mating season, and other forms of selective pressures rather than environment-dependent selection may contribute to the evolutionary maintenance of male types within populations. Assuming female vicinity as a proxy of mating opportunity, we explored the effect of snow depth variations on the elevational overlap between females, and territorial and non-territorial male chamois, Rupicapra rupicapra, in three consecutive rutting seasons. In snow-free periods, females overlapped with non-territorial males, but not with territorial ones. With increasing snow depth, females and territorial males progressively occupied similar elevations. Our results suggest that snow cover variations may impose changes in the spatial distribution of males and females. In turn, weather stochasticity over multiple ruts, rather than within-rut environment-dependent selection, may impose variations in mating opportunities of ARTs, possibly contributing to the coexistence of different phenotypes within populations.

Population parameters of ringed seals (Phoca hispida Schreber, 1775) in the Svalbard area

1987 ◽  
Vol 65 (4) ◽  
pp. 1021-1027 ◽  
Author(s):  
Christian Lydersen ◽  
Ian Gjertz
Keyword(s):  
Sex Ratio ◽  
Ringed Seal ◽  
Adult Males ◽  
Population Parameters ◽  
Phoca Hispida ◽  
Age Class ◽  
Ringed Seals ◽  
Males And Females ◽  
The Mean ◽  
Sexually Mature

Samples were taken from 284 ringed seals (Phoca hispida) in the Svalbard area during April–July 1981 and March–April 1982. The age of 283 seals was determined by reading annuli in the cementum of the canine teeth. The mean age of the males was 11.3 years, and of the females, 14.9 years. Females were found to be significantly older than males. The mean length of sexually mature ringed seals was 128.9 cm for both sexes. The mean weight of adult males and females was 53.5 and 61.4 kg, respectively. Females were found to be significantly heavier than males. The sex ratio was 47.8% males and 52.2% females. Studies of microscopic sections of testis and epididymis from ringed seal males showed that 63, 75, and 80% of 5-, 6-, and 7-year-old animals, respectively, were sexually mature. The weights of testis and epididymis, diameters of tubuli, and the size of testis all showed a marked increase in the 5-year age-class. Macroscopic sections of ovaries from ringed seal females showed that 20, 60, and 80% of 3-, 4-, and 5-year-old animals, respectively, were sexually mature. The size of the ovaries showed a marked increase in the 5-year age-class. The ovulation rate of ringed seals from Svalbard was calculated to be 0.91.

scholarly journals Alternative reproductive tactics increase effective population size and decrease inbreeding in wild Atlantic salmon

2014 ◽  
Vol 7 (9) ◽  
pp. 1094-1106 ◽  
Author(s):  
Charles Perrier ◽  
Éric Normandeau ◽  
Mélanie Dionne ◽  
Antoine Richard ◽  
Louis Bernatchez
Keyword(s):  
Atlantic Salmon ◽  
Population Size ◽  
Effective Population Size ◽  
Alternative Reproductive Tactics ◽  
Effective Population ◽  
Reproductive Tactics

scholarly journals Alternative reproductive tactics and sex‐biased gene expression: the study of the bulb mite transcriptome

2014 ◽  
Vol 4 (5) ◽  
pp. 623-632 ◽  
Author(s):  
Michal T. Stuglik ◽  
Wiesław Babik ◽  
Zofia Prokop ◽  
Jacek Radwan
Keyword(s):  
Gene Expression ◽  
Alternative Reproductive Tactics ◽  
Reproductive Tactics ◽  
Bulb Mite
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