References: the simple art of politeness

November 29, 2011

Every true hobbyist who endeavours to share his/her knowledge and experiences of aquarism through a website will eventually encounter the nagging irritation of plagiarism by other hobbyists.

Plagiarism is an imitation of others’ texts and ideas, claimed as one’s own. I must stress that this includes slight modification of the text and translations. Rather than preaching the legal issues surrounding the issue, I wish to highlight something just as important – the disrespect it infers.

When you copy+paste the text from someone else’s website, you are copy+pasting all the time and effort they put into writing the article and gaining the knowledge that they poured into it. It is impolite (at the very least) to not ask permission and to not reference your sources, and doing so will earn you far more respect than the stolen text will.¬†Needless to say, there is a very similar issue with photographs. Ask for permission before use, and reference the owner/source.

Plagiarism is not only highly impolite and disrespectful, but it is also extremely easy to avoid. Be civilised, hobbyists; acquire permission and give references!

An example of how to reference a website is as follows:

Sources:

Green, J. ‘http://www.atyidae.wordpress.com’.


My to do list for my blog!

November 20, 2011

I’m sure you’ll find this blog post thrilling… Anyway, this what you can now expect to come in the following days and weeks:

  • Write up on Aquatics Live (Saturday). Met aquarists and a couple of names familiar from the shrimp fora!
  • Information profiles for all described Sulawesi shrimp. Now that I am away from home at Uni I will have less time and money for keeping the shrimp, so I will focus on the blog instead.
  • Information pages on aquarism and shrimp ‘science’ ūüėČ
  • Photographs!

So you have a lot to look forward to!


Paying for genotypes

October 22, 2011

 

The Taiwan Bee strains, as many of you will know, come with a high price tag. It is only recently that this price¬†dropped to as low as ¬£40 per King Kong shrimp on the continent, and this is now considered phenomenally cheap. However, many hobbyists decide to take the cheaper option… Taiwan Bee hybrids.

Taiwan Bee hybrids are Red Bee, Gold Bee or (more commonly) Black Bee shrimp that have the allele(s) for Taiwan Bee mutations locked up in their genetics. As these alleles are recessive to the normal Bee alleles, they are not shown in the expressed phenotype in these heterozygous individuals, except very rarely and subtly Gold Bees (shown as a blue hue on the carapace).

Taiwan Bee hybrids are not a new concept, but it is important to be cautious if you should decide to invest in these rather than the pure strains. With the homozygous pure strains you are not only paying for the shrimp, but also the assurance that this shrimp does indeed have the alleles for Taiwan Bee mutations in its genotype. However, when paying for Taiwan Bee hybrids, you have no assurance that the shrimp have the Taiwan Bee allele(s) in their genotype as it is accepted that it will not show in heterozygous individuals. The obvious implication of this is that any Bee shrimp could be sold as a Taiwan Bee hybrid, regardless of whether this is the case or not.

Photograph by C. Lukhaup.


Follow on Facebook

September 22, 2011

Follow Atyidae on Facebook for more frequent updates, including two new shrimp species!


Colouration

September 10, 2011

Caridina species vary greatly in terms of colouration, from being clear with visible organs to having fully opaque bodies in a range of colours. This is due to the presence or lack of pigments and pigment complexes, and their respective distributions.

Pigments and proteins

Pigments are chemicals that absorb certain wavelengths of visible light and transmit the remaining wavelengths. This results in us interpreting the light (and thus the object) as coloured. Different pigments produce different colours and tones due to their structures.

A pigment found in an organism is called a biopigment. The most common biopigments in Caridina shrimp are carotenoids, which appear to be obtained through diet. These pigments can form complexes with proteins, altering the colour or tone produced, and these complexes are known as carotenoproteins. When these complexes are broken, the colour and tone of the original carotenoid is expressed instead. This is demonstrated by how shrimp turn red when cooked: the complexes between the pigment and protein are broken due to the high temperature and the reddish colour of the carotenoid replaces the natural colours of the shrimp produced by the carotenoproteins .

In Caridina shrimp the biopigments are found either in the cuticle, specifically the exocuticle, or in specialised cells called chromatophores. The former are responsible for colouration of the exoskeleton, whereas the latter are responsible for colouration within the body tissue.

Filing those chromatophores

Chromatophores are categorised by their respective colour of pigment, simply by stating the colour e.g a red chromatophore. There are four main categories of chromatophores by this convention:

  • Black¬†chromatophores, containing ommochromes, which absorb all wavelengths of light
  • Red¬†chromatophores, generally containing astaxanthin
  • Yellow¬†chromatophores, generally containing lutein
  • White¬†chromatophores, contain pigments that reflect all wavelengths of light, such as pterines or certain flavins

Determining colouration

The colour and colour intensity we see with the naked eye is determined by a number factors. At a molecular level, the type of pigment and its complexes with proteins determines the light absorbed and reflected. Then there is the number of pigments, the combination of pigments and their distribution within the chromatophore. Then there is the combination of chromatophores and their density within tissue. It is a similar case for the pigmentation of the exocuticle. On top of these, there are even more factors, such as sclerotisation of the cuticle which gives an amber hue, or the wavelengths present in the light they are exposed to.

The colouration of shrimp is far more complex than one might assume, and even this article is merely scratching the surface. However, good knowledge of how colouration works in shrimp allows the aquarist to enhance the colour of their shrimp in harmless ways.

More on that later…


What is a Caridina shrimp?

September 5, 2011

Taxonomically, Caridina shrimp are organisms under the genus Caridina. Below is a table on the full scientific classification of a Caridina species, Caridina caerulea.

Taxonomic Rank  Classification  Physical characteristics
 Domain   Eukaryota  Cells contain membrane-bound structures (organelles).
 Kingdom   Animalia   Cells lack cell walls; Multicellular with few exceptions; Heterotrophic; Motile in some form.
Phylum  Arthropoda   Lack vertebrae; Segmented body; Jointed limbs; Chitinous exoskeleton.
 Subphylum   Crustacea  Biramous limbs; Nauplius larvae.
 Class  Malacostraca  19-20 segments: cephalon (5), thorax (8), abdomen (6-7).
 Subclass  Eumalacostraca  19 segments:  cephalon (5), thorax (8), abdomen (6).
 Superorder   Eucarida Capace fused to all thoracic segments; Stalked eyes. 
 Order Decapoda  10 legs; Full carapace.
 Suborder Pleocyemata  Eggs incubated on female’s pleopods.
 Infraorder Caridea  2nd abdominal somite overlaps adjacent; 2 pairs of chelate pereiopods; Complex larval stages; Lamellar gill structure.
 Superfamily  Atyoidea  Mature form inhabits freshwater, few exceptions.
Family Atyidae  Chelae have brushes.
 Genus  Caridina  (Mainly in subtropical and tropical freshwater habitats). 
 Species  Caridina caerulea  Full species description.

Caridina caerulea macros

August 30, 2011





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