Female genomic response to mate information

Discussions on cichlid behaviour in nature & captivity.

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Bojan Dolenc
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Female genomic response to mate information

Post by Bojan Dolenc » Fri Nov 26, 2010 1:51 pm

Julie K. Desjardins, Jill Q. Klausner, Russell D. Fernald. Female genomic response to mate information. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.1010442107
http://www.physorg.com/pdf209815308.pdf
Abstract
Females should be choosier than males about prospective mates because of the high costs of inappropriate mating decisions. Both theoretical and empirical studies have identified factors likely to influence female mate choices. However, male–male social interactions also can affect mating decisions, because information about a potential mate can trigger changes in female reproductive physiology. We asked how social information about a preferred male influenced neural activity in females, using immediate early gene (IEG) expression as a proxy for brain activity. A gravid female cichlid fish (Astatotilapia burtoni) chose between two socially equivalent males and then saw fights between these two males in which her preferred male either won or lost. We measured IEG expression levels in several brain nuclei including those in the vertebrate social behavior network (SBN), a collection of brain nuclei known to be important in social behavior. When the female saw her preferred male win a fight, SBN nuclei associated with reproduction were activated, but when she saw her preferred male lose a fight, the lateral septum, a nucleus associated with anxiety, was activated instead. Thus social information alone, independent of actual social interactions, activates specific brain regions that differ significantly depending on what the female sees. In female brains, reproductive centers are activated when she chooses a winner, and anxiety-like response centers are activated when she chooses a loser. These experiments assessing the role of mate-choice information on the brain using a paradigm of successive presentations of mate information suggest ways to understand the consequences of social information on animals using IEG expression.
Change in habit, producing change of function, is the main cause of the production of change in living structure. F. Wood Jones (1953) Trends of life

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Bojan Dolenc
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Egg-spots in Astatotilapia burtoni

Post by Bojan Dolenc » Tue Jun 21, 2011 4:24 am

Astatotilapia burtoni was the species used by Wickler in 1962 in formulating his theory regarding the purpose of eggspots. Now scientists have studied the way these spots develop as the young fish grows from fry to adulthood.
...
For further information see: Heule, C. & W. Salzburger (2011): The ontogenetic development of egg-spots in the haplochromine cichlid fish Astatotilapia burtoni. Journal of Fish Biology (2011) 78, 1588–1593. doi:10.1111/j.1095-8649.2011.02944.x
Change in habit, producing change of function, is the main cause of the production of change in living structure. F. Wood Jones (1953) Trends of life

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Bojan Dolenc
Posts: 222
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Location: Slovenia - Ljubljana
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Re: Female genomic response to mate information

Post by Bojan Dolenc » Thu Jun 30, 2011 12:46 am

New one 8)
Lehtonen, Topi K. and Axel Meyer (2011): Heritability and adaptive significance of the number of egg-dummies in the cichlid fish Astatotilapia burtoni. Proceedings of Royal Society B - 2011 vol. 278 no. 1716 p.p. 2318-2324.
http://rspb.royalsocietypublishing.org/ ... 8.abstract
Abstract

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.

* body condition
* dominance hierarchy
* narrow sense heritability
* intraspecific variation
* key innovation
* signal value
Change in habit, producing change of function, is the main cause of the production of change in living structure. F. Wood Jones (1953) Trends of life

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