Breeding Macrobrachium pilimanus

[Veneer]

I've just obtained an ovigerous "chameleon shrimp" (presumably M. pilimanus). Though I unfortunately have no experience with saltwater setups, I'd like to take a shot at rearing some of the resultant larvae to adulthood.

I understand that the young of this species adhere to "low-order" development, but was unable to locate any literature on typical larval growth schedules, optimum salinity, and appropriate foodstuffs. Would care protocols differ significantly from those for Caridina japonica?

[badflash]

I think if the larva need saltwater then you should follow the methods used for M. Rosenbergii. ~ 12 ppt salinity. freshly hatched brine shrimp for the 1st 2 weeks, than a transition to egg based custard food for the last two weeks.

PM me and I'll send you a manual on Rosenbergii. The file is big, like 5 meg.

[wklotz]

Hallo Veneer!

All members of the Macrobrachium pilimanus scpecies complex can be reared in freshwater of median to high hardness.
The larva of theese species do not need any saltwater for development.

Regardless the scpecies general sold as "chameleon shrimp" an which is pictured on:
http://www.wirbellose.de/arten.cgi?acti ... &artNo=034
is no M. pilimanus nor a member of this scpecies group. Whithout many doubt this shrimp belong to the species Macrobrachium scabriculum, needing Saltwater for larval development.

Regards
Werner

[Mustafa]

I understand that the young of this species adhere to "low-order" development,

There is no such thing as "low order" or "high order" in scientific literature. This is something made up by some hobbyists in Singapore (and neighboring countries), and outside Singapore nobody else uses it. It's advantageous to use the terms in scientific literature to keep things compatible. Most scientists refer to the shrimp who have saltwater larvae as going through "normal larval development." And, that is really "normal" as the vast majority of shrimp species do need a saltwater larval phase. Then you have a bunch of terms in between, but the most important ones are "abbreviated larval development," where several larval stages are skipped and hence the amount of time the shrimp spend as larvae is much shorter than in the "normal larval development type." You can have various degrees of abbreviation, which cover a whole range of species. In my experience most "abbreviated larval development" type shrimp species seem to be able to grow up in complete freshwater. Hence, there seems to be a connection between larval salinity requirements and number of larval stages.

Finally, you have "suppressed larval development" type species, where no larvae at all are produced, but benthic "miniature" versions of the adults.

I have used this categorization in my shrimp species description for a reason (see above), so let's try to use this in the forum, too.

[Terran]

Does anyone know if there are any articles regarding the evolution of these different types of juvenile development...

I imagine that the fossil record for larva ia nonexistent....But maybe there’s some genetic cladograms out there....


Does anyone know of any strictly freshwater species that still have a normal larval development but the larva do not need access to brackish or saltwater?

I wonder what it is about the larval stages that requires the salt water...

[wklotz]

Hi Terran!

Does anyone know if there are any articles regarding the evolution of these different types of juvenile development...

Yes, there are some papers about this.
Some examples:

Tiwari K.K., (1955)
Trends of evolution in the hendersoni group of species of Palaemon Farbr. (Crustacea: Decapoda)
Bulletin of the National Institute of Science of India, New Delhi, 7:189-197

Tiwari K.K., (1955)
Distribution of the Indo-Burmese freshwater prawns of the genus Palaemon Fabr. and its bearing on the Satpura hypothesis
Bulletin of the National Institute of Science of India, New Delhi, 7:230-239

Jalihal D.R., et al. (1993)
Evolution of larval developmental patterns and the process of freshwaterization in the prawn genus Macrobrachium Bate, 1868 (Decapoda, Palaemonidae)
Crustaceana 65 (3) 365-376

Murphy N.P., Austin C.M., (2005)
Phylogenetic relationships of the globally distributed freshwater prawn genus Macrobrachium (Crustacea: Decapoda: Palaemonidae): biogeography, taxonomy and the convergent evolution of abbreviated larval development
Zoologica Scripta 34 (2): 187-197

Does anyone know of any strictly freshwater species that still have a normal larval development but the larva do not need access to brackish or saltwater?

Of course there are some true freshwater species, showing normal or prolonged larval development. Caridina kempi as an example, passing through 6 larval stages.

Jalihal, D.R., Sh. Shenoy & K.N. Sankolli (1999)
Larval development of the Indian atyid shrimp Caridina kempi reared in the laboratory
College of Fisheries , Ratnagari

Regards Werner

[Mustafa]

Does anyone know if there are any articles regarding the evolution of these different types of juvenile development...

I imagine that the fossil record for larva ia nonexistent....But maybe there’s some genetic cladograms out there....

Well, it's actually pretty easy to figure out the evolution. As it stands today it looks like all freshwater shrimp species that we concern ourselves with have their origins in the ocean. Hence, it's not surprising that the larvae of a lot of species require saltwater. That's because those species are relatively "recent" (in geological terms) immigrants to freshwater. Most saltwater shrimp and lobsters and relatives also produce larvae that spread with the ocean currents. But there are shrimp species even in the ocean that have abbreviated larval development. Some sponge dwelling shrimp species (Synalpheus sp.) and their relatives come to mind.

Does anyone know of any strictly freshwater species that still have a normal larval development but the larva do not need access to brackish or saltwater?

Well, Macrobrachium lanchesteri and relatives come to mind, although they are of the abbreviated larval development type. It's just that they are not as abbreviated as others and hence they still produce larvae, which, however do not need saltwater. Here is a thread showing some pictures of their larvae:

viewtopic.php?t=1583&postdays=0&postorder=asc&start=0

I assume that the Eurasian shrimp Atyaephyra desmaresti comes close to being called "normal" as far as larval development is concerned. As far as I know their larvae do not need saltwater for development. Correct me if I 'm wrong, Werner.

One final note. Even among species that could be called "normal larval development" types, there are differences in number of larval stages. In other words, even the terms "normal", "abbreviated" and "suppressed" are just simplifications of what's really going on there.