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“Let’s shed a little light”


caridina English Edition - epaper ⋅ Ausgabe 3/2019 vom 30.07.2019

Monika Pöhler shares her knowledge of Tibee breeding, challenging other breeders to an open exchange of experiences.

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Bildquelle: caridina English Edition, Ausgabe 3/2019

“Intermediate” Tibee type, an exceptional “Safari” specimen, from positive selection


Photo: Chris Lukhaup

When breeding dwarf shrimp, the research of the genetic backgrounds and the causalities as well as the verification or falsification of theories developed in practical breeding are a good means of countering the problems created by uncontrolled hybridization (see plage 14). Well-founded knowledge, shared with a wide base of enthusiasts will provide hobbyists and professional breeders ...

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... with the tools they‘ll need for self-help, so they won‘t accidentally further and spread unwanted traits in their shrimp populations.

Negative results after years of ambitious work can be incredibly frustrating, however, on the other hand: If you apply well-founded knowledge of the interdependencies and the genetic background of certain breeds, your results will be highly satisfactory. This applies to progressive crossbreeding as well as to conservative breeding or even back breeding.

MY PERSONAL CONTRIBUTION

In May 2018, I was invited to the “Warszawskie dni Akwarystyki“, the Warsaw Aquarium Days in Poland, and I was asked to share my experiences and the findings from ten years of practical Tibee breeding. There I presented my system of five levels that build upon each other. Here, the intial crossbreed between Tiger and Bee is considered as well as the classic phenotypes and the way the current high-bred variants were created.

These five levels exclusively apply to my results of the original hybridization ofCaridina mariae (Tiger shrimp) withCaridina logemanni (Bee shrimp) in the year 2008. Back then, both species were still calledCaridina cf.cantonensis . The genetic disposition of their offspring is what is generally called a “Tibee”, the short form of Tigerbee. My breeding projects have been going on for many years, and I’ve never crossed in any otherCaridina species. However, there are shrimp strains by other breeders that look a lot like my breeds, whose origins are unclear. I’m not talking about these parallel developments here.

Classic Tibee breeding is highly complex. I have attempted to boil it down to simple schematics in order to present my system more clearly. My sincere thanks go to Ricardo Castellanos Valdez for his help! In this article I’d like to explain and describe the first and second levels of my breeding system.

How I started my crossbreeding project

When I started my crossbreeding project in 2008, the name a shrimp carried still permitted the identification of its “bloodline” (its lineage). The genetic disposition of a Crystal Red shrimp just differed in color-in its phenotype-from the wild-type Bee shrimp found in Chinese streams. The red variant was selectively bred by Hisayasu Suzuki, Japan, from innumerable wild-colored Bee shrimp in the 1990s. In the following years, this variant was first bred in Japan, later on also in Germany and many other countries. The year-long selective breeding resulted in a more intense basic color (white) and pattern color (red). These “old-school” red-colored Bee shrimp had alternating bands, and the highest level that could be reached after years of selective breeding was a three-or four-banded pattern. Moreover, there were Bee shrimp whose red bands widened and spread almost over the entire body, crowding out the basic color, and leaving only a white margin on the pleon and on the head. This selection was called Super Crystal Red.

Original photo of a Crystal Red from the year 2009.


Photo: Frank Logemann

Phenotypes ofCaridina logemanni, selectively bred from wild-type shrimp.


Illustration: Ricardo Castellano

Until the so-called Japanese “Red Bee“ entered the scene, these levels were the end of the line. The patterns did not develop any further, and the white basic color did not spread beyond the clear-cut borders of the red bands.

In 2008, I used true-breeding red Bee shrimp and Tiger shrimp for my crossbreeding project. The Bees were bred in Germany and had been selectively bred for homogenous three and four bands. Their lineage could be traced back to wild-type shrimp. The Tiger shrimp I used could be called true-breeding too, according to the standard back then as well as to current knowledge.

During these times, the “Blue Tiger shrimp” with its striking orange eyes was especially popular. This variant had been bred from shrimp with a transparent basic color and an intense blue body color. Besides the Blue Tiger shrimp, the so-called “Super Tiger“ and “Orange Tail Tiger“ shrimp were imported and kept by many breeders. Those two variants probably weren’t subject to intense selective breeding, though, and the lineage leading back to their wild-type ancestors was presumably very short. The dominant tiger stripes, looking like brackets, with three leaning towards the back and two leaning towards the front, are of a more or less dark brown color (pattern color) in all Tiger shrimp.

Various Tiger shrimp variants, circa 2008,Caridina mariae .


Illustration: Ricardo Castellano

I had comparable results when crossbreeding Bee shrimp with the aforementioned two variants in the lower levels. All in all, Blue Tigers brought more interesting and most surprising results, though – probably due to their recessive orange eye color and the traits that are combined with that characteristic, and due to their blue body color

Original photo from 2009: A Crystal Red with nice alternating bands. This pattern, called three-band, used to be one of the highest grades.


Photo: Frank Logemann

NOT EVERY RED SHRIMP IS A CRS

The first confusion was created right at the beginning of the shrimp-breeding boom, since a Crystal Red Shrimp is not the same as the Red Bee shrimp imported from Japan later on, and it is definitely different from the PRL (Pure Red Line), which was created much later on. Yet all these shrimp variants are frequently called CRS (short for Crystal Red Shrimp), especially in English-speaking countries.

Wild-caught “Orange Tail“ Tiger shrimp, original photo from 2009.


GENOTYPE / PHENOTYPE

The term “genotype” refers to the genetic disposition of an organism-the combination of all genes that are behind a trait. The term “phenotype” describes the visible traits of an organism, or the visual appearance. The phenotype is not only influenced by the genotype, but also by the environment.
Source: www.drze.de/im-blickpunkt/praediktive-genetische-testverfahren/module/genotyp-phaenotyp

DESCRIBING THE LEVEL 1 TIBEE PHENOTYPE

The first-level phenotype is easily described, since the inheritance follows the First Mendelian Law, the Rule of Uniformity. The offspring of the first generation (F1) all look quite similar in pattern and color, the differences are only marginal. The Bee traits recede, and the dark brown stripes of the Tiger pattern are predominant. The only Bee traits that are visible are the clearly pronounced white chromatophores, which are grouped around the dark stripes, especially on the back of the shrimp. Despite being very similar in color and pattern, some of the females display a tendency to grow very large (heterosis ).

A black Tiger shrimp variant


Photo: Ricardo Castellanos Advert

The fertility of the F1 generation may be very low, however, offspring is possible. Some of the females may never form eggs in their ovaries and never develop the so-called saddle, or, if they do, the saddle may recede. Other females that do get berried may lose their eggs, or get berried very late in their life.

Some of the males are disinterested in the females, or go on mating “dances” without the presence of a recently molted female (which might be due to misinterpretation of pheromones), some are precocious, others do not grow to full size and stay very small.

THE FIRST GOALS ARE REACHED IN LEVEL 2

Illustration: Ricardo Castellano

A Original cross
B F1 generation
C Pool of intermediary shrimp
D Other traits worthy of selective breeding, like changes in the exoskeleton (won’t be described in detail here)
E Start of the Safari linie
F Selection group 1: phenotypes with “expand color on/off”, “fading/fortify” traits
G Selection group 2: Bee phenotypes
H Selection group 3: pure color phenotypes
H1 The black of the blue-albino phenotypes
H2 The seemingly black pattern of wild-type Tiger and Bee phenotypes is actually brown

The majority of the Level-2 Tibee phenotypes consists of so-called intermediary shrimp. Here we have a mixture of dark brown patterns, color patches and transparent areas that is hard to define in a clear-cut way. As a rule, Tiger traits like stripes and transparent areas are still dominant, however, we do have a hint of a Bee pattern that is visible on the upper side of the pleon.

My first goal in my crossbreeding project was the creation of a “White Tiger”, shrimp with a striped tiger pattern and a white basic color. I singled out the first shrimp that started to resemble this goal from the dizzyingly huge pool of the intermediary shrimp. In our graph, Level 2 signals the start of the Safari line (fig. E).

Intermediary Tibee type with intense white pigments, brown stripes and a headband that is starting to dissolve, from positive selection for the Safari trait.


Furthermore, I also singled out some wild-type phenotypes from my Level 2 Tibees, which I found especially attractive, and I divided them into three breeding groups (F = expand – color on/off – fading/ fortify*, G = Bee phenotypes, H = pure colors) with different complex traits. These traits appear in approximately one to three percent of the entire Level 2 population. They were special because they formed the basis for the development of today’s phenotypes.

*I will explain the characteristics of this strain in the following in more detail.

FOCUSSED LEVEL 2 BREEDING RESULTS

FIRST GROUP: EXPAND COLOR ON/OFF – FADING/FORTIFY (FIG. F)
The shrimp of this complex group, whose phenotypes are known as Snow Bee or Golden Bee, Black Tiger and Ghost Bee in the hobby, are either (almost) completely covered in chromatophores of just one color (expand color on) or lack all pigmentation (expand color off). Totally transparent shrimp of this group have orange eyes (OE), a typical Tiger shrimp trait, however, the solid, fully colored “expand color on” variant has dark eyes, or normal eyes, as we call them (NE).

Snow-type Tibee, based on a brown pattern color with the typical, weak white pigmentation all over its body.


Photo: Chris Lukhaup

The phenotypes belonging to the “expand color on” type can be divided into two subvariants. The first is completely covered in the white basic color of the Bee banded pattern in a lower intensity (expand – basic color on / fading – pattern color off), whereas in the other variant, the tiger stripes have expanded and intensified to black, and cover the body almost entirely (expand – pattern color on/fortify – basic color off). In comparison, all the other Tibees of the second level that have white-pigmented bodies and fragmented stripes and bands belong to the type “expand off – basic color on – pattern color on”.

Snow-type Tibee, an exceptional speciment with a reddish pigmentation starting to form on the head.


Black Tiger type Tibee with a rusty layer.


Photo: Chris Lukhaup

SECOND GROUP: BEE PHENOTYPES (FIG. G)
This breeding group comprises all phenotypes resembling the original Bee shrimp used in the first crossbreeding cycle. However, this group differs from the original Bee shrimp in two aspects: The intensity of the white chromatophores may vary greatly and from shrimp to shrimp, with a very clear tendency towards fading, and moreover, the white chromatophors have expanded on the body, thereby reducing the bands on the pleon. Here, the so-called Tigertooth and V-Band patterns appear all of a sudden, as well as another new trait: We now have maro-ten spots on the head.

OE Tiger shrimp from a population whose stripes were basically brown, but whose members were selectively bred for red to purple.


The color of the stripes of pure-bred Red Tiger variants is not an albinotic red but was selectively bred for the intense red color from the original reddish brown.


Photo: Ricardo Castellanos

An intermediary Tibee type with weak white and brown stripes and a head band that’s starting to dissolve.


THIRD GROUP: PURE COLOR PHENOTYPES (FIG. H)
In the third group we have those L2 Tibees whose pattern color differs from the majority of brown-patterned shrimp. Brown is the dominating pattern color, even though dark brown Bee shrimp are often called “Black Bee”.

The theory of colors tells us: A dark brown color that appears almost black is created by the presence of all the basic colors: blue, red and yellow, in more or less the same proportion. Wild-type Tiger and Bee shrimp usually have the genetic disposition to form all three colors in their pigments. Depending on their proportion, different shades of brown are created.

The shrimp I chose as a basis for my project all had yellow chromatophores forming part of their pattern color, too, but their number was very low in comparison with the red and blue ones. Moreover, in Blue Tiger shrimp, the yellow pigments of the body color were even more strongly reduced so almost only blue pigments remain. In addition, the original Crystal Red shrimp strain that I used had no blue pigments at all. When it comes to the pattern color, we could rightfully consider it an albino, and that is how the pure, intense red of the red Bee shrimp is created.

Intermediary Tibee type, exceptional specimen of the positive selection for the Safari trait: albinotic red stripes and intense white pigmentation


Photo: Chris Lukhaup

For this last group, I picked specimens with purecolor patterns from my large pool of brown-patterned shrimp. On the one hand, I found some with a “pure red” (red albino) pattern, and on the other hand I discovered shrimp with a newly created “pure blue” color, which is so dark that the human eye perceives it as “pure black”, but which entirely lacks red pigments (blue albino, fig. H1) and is interspresed with only very few yellow pigments.

CONCLUSION
Whereas the second and the third group display interesting traits that can be traced back to genetic recombination, like the creation of a new color, the alterations of the Bee pattern or a new tendency towards fading or intensifying colors, in my opinion, serious shrimp breeders need to reconsider especially the phenotypes of the first group (fig. F), up to now known as Snow White or Golden shrimp, Black Tiger shrimp, or Ghost Bee Shrimp, which are often considered to be either Bee or Tiger shrimp but are actually hybrids.

In my assumption, all these three phenotypes are created by a defective melanin synthesis, and all of them are passed on recessively in the classic definition of the Mendelian Laws. We may therefore look forward to the effects all of this may have for the higher levels three through five.