Mating Behavior of Macrobrachium crenulatum

[Veneer]

Yesterday evening, I video-taped mating behavior in some M. crenulatum I recently shipped back from Puerto Rico: http://www.vimeo.com/1256512.

As far as I know, this is the first such footage ever taken for crenulatum. The female was being temporarily housed in a plastic "Kritter Keeper" submered within the larger aquarium where the male was residing. I had offered shrimp pellets to all of my new shrimp the night of their arrival; this female crenulatum was the only one to leave the food untouched. I attributed this to the stress of transport, but around 1 PM the following day, I noticed it to have molted. The cast shell, suprisingly enough, was left completely untouched. Around 12 hours later, I happened to observe the male probing the top of the plastic container, and opened the lid to see what happened next.

The eggs (thousands upon thousands, and quite miniscule) descended amongst the pleopods around 30 minutes later. In the meantime, the male set about consuming the fresh exuvium, which seemed compellingly similar to the "nuptial gift" phenomenon in certain predatory insects and arachids. At present, I don't have any other data points for crenulatum, so it's impossible to determine whether the male's meal was incidental or par for the course.

I was surprised that the female cuticle remained soft enough for spermatophore placement so long after molting. Perhaps anti-hardening agents are released into the post-ecdysis exoskeleton by reproductively receptive females, since the window of opportunity for mating might otherwise be quite narrow if population density is low or concentrated downstream of the female's pool.

I will try to rear the resultant young.

[Veneer]

Prior to introduction of male


Post-copulation


Eggs visible through pleura

[Neonshrimp]

Thanks for the information and nice photos, please keep us updated on this one

[Mustafa]

In the meantime, the male set about consuming the fresh exuvium, which seemed compellingly similar to the "nuptial gift" phenomenon in certain predatory insects and arachids. At present, I don't have any other data points for crenulatum, so it's impossible to determine whether the male's meal was incidental or par for the course.

It's not a "nuptial gift." Since you only have the male in the tank, and the female is unable to eat so soon after molting, the male got to eat the shed shell/exuvia. If you had had other females in the tank or even a completely different species of macro, then whoever had gotten to the exuvia first would have eaten it. In their natural river habitats the exuvia often float downriver, far from the male, and gets consumed by anything that gets it (including crabs, fish etc.).

[pixl8r]

Veneer,

Do you have brackish hatcheries setup? I think I've PM'd you about what I'm currently doing, attempting to breed M. scabriculum. I made two hatchery/nursery tanks by taking 5g buckets and large plastic bowls. I cut the bowls so that they fit tightly inside the bottom of the buckets, then I used silicone to seal the rim. That way I have the cylindrical container, without any right angles.

My only problem right now is getting another female shrimp to carry eggs! Do they make invertebrate viagra?

[Veneer]

Veneer,

Do you have brackish hatcheries setup?

I have some five-gallon aquaria and tubs at around 17.5 ppt salinity with Xiphocaris elongata and other Macrobrachium larvae. I'll be using something similar for the crenulatum.

[pixl8r]

Great! I hope that more people get interested in breeding these types of shrimp. Once I have anything to report, I'll be sharing my journey here. Still waiting for my shrimp to get in the mood. Perhaps some Berry White will help.

[Mustafa]

I have bred M. crenulatum before (a few years ago). If it helps any, the larvae don't eat anything the first few days and then immediately take inanimate food. I used 100 micron golden pearls, but 50 micron may work better. You can see the larvae latch on to the golden pearls and float around with them. My salinity was at about 20-22 ppt but I'm sure there is a range of salinity values that the larvae can develop under as they (the larvae) are estuarine creatures.