scholarly journals Androgen receptors in a cichlid fish,Astatotilapia burtoni: Structure, localization, and expression levels

2007 ◽  
Vol 504 (1) ◽  
pp. 57-73 ◽  
Author(s):  
Lene K. Harbott ◽  
Sabrina S. Burmeister ◽  
Richard B. White ◽  
Mike Vagell ◽  
Russell D. Fernald
Keyword(s):  
Androgen Receptors ◽  
Cichlid Fish ◽  
Expression Levels ◽  
Astatotilapia Burtoni

scholarly journals Heritability and adaptive significance of the number of egg-dummies in the cichlid fish Astatotilapia burtoni

2011 ◽  
Vol 278 (1716) ◽  
pp. 2318-2324 ◽  
Author(s):  
Topi K. Lehtonen ◽  
Axel Meyer
Keyword(s):  
Species Recognition ◽  
Cichlid Fish ◽  
Fertilization Success ◽  
Narrow Sense Heritability ◽  
Key Innovation ◽  
Bright Spots ◽  
Spot Number ◽  
Astatotilapia Burtoni ◽  
Important Trait ◽  
High Degree

Cichlid fishes are a textbook example of rapid speciation and exuberant diversity—this applies especially to haplochromines, a lineage with approximately 1800 species. Haplochromine males uniquely possess oval, bright spots on their anal fin, called ‘egg-spots’ or ‘egg-dummies’. These are presumed to be an evolutionary key innovation that contributed to the tribe's evolutionary success. Egg-spots have been proposed to mimic the ova of the mouthbrooding females of the corresponding species, contribute to fertilization success and even facilitate species recognition. Interestingly, egg-spot number varies extensively not only between species, but also within some populations. This high degree of intraspecific variation may appear to be counterintuitive since selection might be expected to act to stabilize traits that are correlated with fitness measures. We addressed this ‘paradox’ experimentally, and found that in the haplochromine cichlid Astatotilapia burtoni , the number of egg-spots was related to male age, body condition and dominance status. Intriguingly, the egg-spot number also had a high heritable component (narrow sense heritability of 0.5). These results suggest that the function of egg-spots might have less to do with fertilization success or species recognition, but rather relate to mate choice and/or male–male competition, helping to explain the high variability in this important trait.

Arginine vasotocin regulates social ascent in the African cichlid fish Astatotilapia burtoni

2015 ◽  
Vol 212 ◽  
pp. 106-113 ◽  
Author(s):  
Lin S. Huffman ◽  
Flora I. Hinz ◽  
Sophie Wojcik ◽  
Nadia Aubin-Horth ◽  
Hans A. Hofmann
Keyword(s):  
Cichlid Fish ◽  
Arginine Vasotocin ◽  
African Cichlid ◽  
Astatotilapia Burtoni

scholarly journals Control of testes mass by androgen receptor paralogs in a cichlid

2021 ◽  
Author(s):  
Andrew P. Hoadley ◽  
Russell D. Fernald ◽  
Beau A. Alward
Keyword(s):  
Cichlid Fish ◽  
Teleost Fishes ◽  
Wild Type ◽  
Regulatory Pathway ◽  
Physiological Plasticity ◽  
Exact Role ◽  
Astatotilapia Burtoni ◽  
Testes Size ◽  
Functional Receptor

AbstractSteroid hormones play numerous important and diverse roles in the differentiation and development of vertebrate primary and secondary reproductive characteristics. However, the exact role of androgen receptors (ARs)—which bind circulating androgens—in this regulatory pathway is unclear. Teleost fishes further complicate this question by having two paralogs of AR (ARα and ARβ) resulting from a duplication of their ancestral genome. We investigated the functional role of these two ARs on testes growth and development by experimentally eliminating receptor function of one or both paralogs using CRISPR/Cas9 genome edited Astatotilapia burtoni, an African cichlid fish. Fish with two or more functional receptor alleles were more likely to be male compared to fish with one or fewer, suggesting that the two paralogs of the receptor may be redundant in regulating early sex determination. In contrast, we found that adult testes size was significantly affected by distinct combinations of mutant and wild-type AR alleles. We present a working model whereby ARβ facilitates testes growth and ARα causes testes regression. This mechanism may contribute to the robust social and physiological plasticity displayed by A. burtoni and other social teleost fish.

scholarly journals A behavioral logic underlying aggression in an African cichlid fish

2020 ◽  
Author(s):  
Beau A. Alward ◽  
Phillip H. Cathers ◽  
Danielle M. Blakkan ◽  
Russell D. Fernald
Keyword(s):  
Physical Aggression ◽  
Social Rank ◽  
Relative Size ◽  
Cichlid Fish ◽  
List Type ◽  
Behavioral Strategies ◽  
Resident Male ◽  
African Cichlid ◽  
Relative Standard ◽  
Astatotilapia Burtoni

AbstractSocial rank in a hierarchy determines which individuals have access to important resources such as food, shelter, and mates. In the African cichlid fish Astatotilapia burtoni, rank is under social control, such that larger males are more likely than smaller males to be dominant in rank. Although it is well known that the relative size of A. burtoni males is critical in controlling social rank, the specific behavioral strategies underlying responses to males of different sizes are not well understood. In this research, our goal was to characterize these responses by performing resident-intruder assays, in which aggressive behaviors were measured in territorial males in response to the introduction of unfamiliar males that differed in relative standard length (SL). We found that the relative SL of intruders played an important role in determining behavioral performance. Resident males exposed to larger (>5% larger in SL) or matched (between 0 and 5% larger or smaller in SL) intruder males performed more lateral displays, a type of non-physical aggression, compared to resident males exposed to smaller (>5% smaller in SL) intruder males. However, physical aggression, such as chases and bites, did not differ as a function of relative SL. Our results suggest that A. burtoni males amplify non-physical aggression to settle territorial disputes in response to differences in relative SL that were not previously considered to be behaviorally relevant.HighlightsRelative size determines social rank in the African cichlid Astatotilapia burtoniResident male A. burtoni respond differently to small size differences in intruder malesResidents perform more non-physical aggression against larger intrudersResidents do not alter physical aggression as a function of differently sized intrudersDistinct behavioral strategies are used against different intruders

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