Biparental mucus feeding in discus

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Bojan Dolenc
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Biparental mucus feeding in discus

Post by Bojan Dolenc » Mon Nov 01, 2010 2:17 am

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Buckley, J, RJ Maunder, A Foey, J Pearce, AL Val & KA Sloman, 2010. Biparental mucus feeding: a unique example of parental care in an Amazonian cichlid. Journal of Experimental Biology 213: 3787–3795.
doi: 10.1242/jeb.042929 - First published online October 29, 2010

Abstract

Vertebrates display a wide variety of parental care behaviours, including the guarding of offspring pre and post nutritional independence as well as the direct provision of nutrients during the early development period. The Amazonian cichlid Symphysodon spp. (discus fish) is unusual among fish species, in that both parents provide offspring with mucus secretions to feed from after hatching. This extensive provision of care, which can last up to a month, imposes a physiological demand on both parents and gives rise to conflict between the parent and offspring. Here, we investigated the relationship between parents and offspring during a breeding cycle, determining both mucus composition (total protein, cortisol, immunoglobulin, and Na+, K+ and Ca2+ concentrations) and the behavioural dynamics of the parent–offspring relationship. Over the course of a breeding cycle, a significant increase in offspring bite rate was recorded, with a concomitant increase in the frequency of turns the male and female parent took at caring for their young. A peak in mucus antibody provision was seen as offspring reached the free-swimming stage, suggesting a role analogous to colostrum provision in mammals. Mucus protein content was lowest during the second and third weeks of free swimming, and a weaning period, similar to that seen in mammalian parental care, occurred when the offspring had been free swimming for ~3 weeks. In many ways, the parental behaviour of discus fish is more similar to mammalian and avian parental care than other fish species, and represents an exciting aquatic model for studying the parent–offspring conflict.

Key words: discus fish, cichlid, immunoglobulin, mucus
http://jeb.biologists.org/cgi/content/a ... 13/22/3787
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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Re: Biparental mucus feeding in discus

Post by Bojan Dolenc » Mon Nov 01, 2010 1:41 pm

This citation from pdf article may be interesting for aquarists:
"Na+, K+ and Cl– were significantly higher in the mucus of wild breeders as opposed to wild non-breeding fish, aquarium-bred breeders and aquarium-bred non-breeders. The difference in the ionic composition of parental mucus between wild breeders and aquarium-bred breeders may be due to the water chemistry of their respective environments."
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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Re: Biparental mucus feeding in discus

Post by Mark Smith » Mon Nov 01, 2010 6:48 pm

"The Amazonian cichlid Symphysodon spp. (discus fish) is unusual among fish species"

Are the authors only refering to one species of Symphysodon, or all of them?

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Bojan Dolenc
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Re: Biparental mucus feeding in discus

Post by Bojan Dolenc » Tue Nov 02, 2010 12:42 am

Mark Smith wrote:"The Amazonian cichlid Symphysodon spp. (discus fish) is unusual among fish species"
Are the authors only refering to one species of Symphysodon, or all of them?

Some citations from pdf article:

"Experimental fish and husbandry
A brood stock of adult discus fish Symphysodon spp., originating from a captive bred strain in Malaysia, were obtained from a commercial dealer and transported to the aquarium facilities of the University of Plymouth."
"Wild fish
A total of 90 non-breeding wild adult fish* were sampled from the Rio Negro, upstream from Barcelos. Fish were caught individually by local fisherman using flashlights and hand nets..."
"Fish that formed breeding pairs were separated into their own 100-litre glass tanks and allowed to spawn on a plastic breeding cone."
"CONCLUSIONS
Parental care duties in discus fish appear to be shared equally between the male and female, with regard to both the parental behaviour directed toward offspring and the provisioning of IgM, total protein, ions and cortisol within parental mucus."

* = wild adult fish = there is no exact identification of species. They are refering to all of discus species.
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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Re: Biparental mucus feeding in discus

Post by Mark Smith » Tue Nov 02, 2010 8:28 am

I see, thanks Bojan.

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