the solitaire
Offline
• • • •
Upload & Sell: Off
|
Chin, I tried getting all the shots I wanted in one go, but working with living animals always shows that even the best plan fails as soon as contact with the enemy is established. With that, this will just become a series of loose posts containing some photos and background information if that's ok for you.
First, our Geosesarma crabitat
 DSC_9757 by b j, on Flickr
It's a 60x40x40 cm enclosure (that's 26"x16"x16" for you imperials
The species in there is called Geosesarma hagen. A small species of crabs from Java, Indonesia. It is said that this is a (mainly) land living species of crabs, and for the adults this is certainly true. The juveniles however appear to prefer a more submersed lifestyle. Geosesarma live in colonies of a substantial size, so even though they can be aggressive to their relatives, and even cannibalistic, they normally get along quite well.
We originally kept 5 of these in a 14"x14"x16" cubicle, but Kristina didn't like the layout of the decorations in that tank, and since we hadn't seen any signs of life for at least 4 weeks, we decided to take the tank apart and clean it. We then found out that 3 of the adults were still alive, and that there were 3 smaller crabs as well. We immediately set up a bigger tank with a bigger water partition.
In that bigger tank we immediately lost sight of all the crabs again. A few months later however (Kristina again dissatisfied with the tank layout) we noticed a few very small crabs in the water partition.
*Most freshwater crustaceans actually take very good care of their brood. Brood care goes as far as that the female carries the eggs until the larvae hatch. From there on, the larvae are carried underneath the abdomen of the female for up to 2 weeks. After these two weeks, the larvae attempt their first forays into the wide world, but return to the adult female after a short exploration. This goes on for a few days. When the larvae are large enough to survive on their own, they are often wiped off the abdomen by the adult female. They span 3-4mm at this stage with a carapax diameter of 1,5-2mm.
With these Geosesarma hagen I observed that the adult female stayed in the water partition with the now juvenile crabs for at least another month. Since the juvenile crabs are territorial and will defend any good hideout they find, as well as food, I advised to restructure the tank once more at this point in the development of the crabs. We increased the size of the water partition once more and added more structures for the weaker crabs to hide. In nature, the weaker individuals will move away and are often eaten by predators. They can't move as far in an enclosure though, so we had to make provisions with what space we could offer.
The new water partition is now large enough to actually add a filter pump
 DSC_9751 by b j, on Flickr
To provide food, we placed a substantial amount of Catappa leaves to the water partition. On the surface of the decaying leaves, microorganisms and small crustaeceans usually find a place to live. These are then eaten by the Geosesarma larvae. Our Geosesarma mom had about 25 young, so just the leaves and whatever decided to grow and mold on the rocks we placed in the water wasn't sufficient. We supplied decapsulated artemia eggs and chlorella powder as additional food.
By now however, our baby crabs are about 2 months old and can eat regular crab food
 DSC_9740 by b j, on Flickr
Fruits, seams, artemia, fish. But they also need dried leaves to form a healthy diet that gives them all the healthy vitamins, proteins and elements they need to succesfully moult.
With another 18 siblings on the hunt for food, dinner for two is a luxury
 DSC_9782 by b j, on Flickr
3 is a crowd though, and here you can clearly see the leftmost crab raising itself in an attempt to chase away the new table guest
 DSC_9786 by b j, on Flickr
Most of the time however, the more aggressive appearing crab is the one losing the standoff, and in most situations a standoff is about as bad as it gets. We do however have at least one crab missing 4 legs on one side. Possible lost a fight, or had difficulties moulting. It's still a rather fast moving crab though, so it will most likely survive and the legs will return after a few more moultings
Next time I will try to get a photo of the adult Geosesarma hagen, and write down a few words on moulting, why it's such a dangerous process and what exactly happens during this process that enables invertibrae to grow
 DSC_9789 by b j, on Flickr
|
