What's new
TerraForums Venus Flytrap, Nepenthes, Drosera and more talk

Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Vampire Crabs MAY be Parthenogenic!

I was doing my daily rounds watering and feeding the critters today and I discovered a new batch of baby crabs in a hank housing only a single female Geosesarma sp. Red Vampire Crab!

Sometime last summer I captured a female vampire crab who had just molted (slower and easy to catch at this time) and put her by herself in a tank with the plan of capturing a male in the main colony and putting him in with her. Well I never caught a male to go with her and yet today I saw about a dozen babies darting around. Now there is a SLIM possibility that she had been mated before I captured her, however two problems with that scenario arise:

1) Molting generally makes insects and creatures who molt "virgins" again so the males sperm packet should not still be with her.

2) Even if she had been mated their gestation/egg carrying period is only around 30 days, she has been alone since molting at least 6 months ago.

The only way I will know for sure is to segregate some babies and raise them to breeding age and see if the females who have never been near a male at maturity will still produce babies. Or simply segregate and raise these babies to maturity and see if they all turn out to be females.
 
Last edited:
Are you sure it's parthenogenesis, as opposed to hermaphroditism? Also, parthenogenetic animals do not necessarily spawn all-female offspring.
 
How neat, hope you have a ton of vampires soon.
 
I don't know what it sort of reproduction mode it is, this particular species known only as Geosesarma sp. "Red" have only just entered captivity in Germany February of 2010, and here in April or May so it is all new to both hobbyists and science. AFAIK hermaphrodites generally still need two of each other to swap genes and parthenogenesis is entirely asexual reproduction. In stick & leaf insects (phasmids) parthenogenic reproduction creates only female offspring so that is where I am coming from as far as my statement on possible sex determination. It will be many months before I can sex these babies, the first batch from last fall in the community tank are still unsexable and have not yet attained adult coloration but are almost 2 cm in size.

There are definite male and females of this crab species, the males are 5 cm & territorial with large claws and the females are a bit smaller & flightier with small claws. I have babies in the community tank and babies in a tank with a single pair but this is the first instance of a single female giving birth with no males around for at least 6 months. Infact I had begun to wonder if she herself died and the snails were coming out of the water to eat the food I gave her because I see the crabs so infrequently but today's discovery of babies indicates she's still in there and doing fine despite not having seen her in some time. They dig a burrow network and that's where they spend most of their time.
 
Last edited:
Are you sure it's parthenogenesis, as opposed to hermaphroditism? Also, parthenogenetic animals do not necessarily spawn all-female offspring.

@emre: can you give an example? i can only think of all female populations....especially since asexual reproduction = clones.
 
All the parthenogenetic insects I am aware of are all female. Males produced only under certain conditions (onset of winter necessitating the production of eggs).
 
@emre: can you give an example? i can only think of all female populations....especially since asexual reproduction = clones.

i think some species have the ability as an option but do not rely on it solely for continuation of the species.......i know is shown up once in a captive bred rattlesnake that hadnt been around a male since the day she was born(her litter mates) and gave birth to a litter of female clones years later.....the species has males available in the native populations so it took alot of ppl by complete surprise.....
 
@rattler: sorry, i should elaborate---in every single example i can think of, regarding parthenogenesis, the offspring are always female. there are never mixed sex offspring.
 
not the story i was thinking of(that one is mentioned in this text) but interesting none the less

http://www.petplace.com/reptiles/rattlesnake-born-of-a-virgin/page1.aspx

---------- Post added at 03:49 PM ---------- Previous post was at 03:49 PM ----------

@rattler: sorry, i should elaborate---in every single example i can think of, regarding parthenogenesis, the offspring are always female. there are never mixed sex offspring.

gotcha, accidentally stumbled on a different one that will interest you check link above....
 
  • #11
guess its as the link says at this point unsure if its a case of a female giving birth to a male without sperm or if its one of those random mutation that will dead end cause it cant be passed on due to the individual being sterile....
 
  • #12
i guess what's amazing is the possibility of recombination...
 
  • #13
Parthenogenic Phasmids will rarely create a "gynandromorph" which is a partial male, usually literally half and half with the left half being male and the right half being female. Sometimes they will be all male looking but they are not fertile because they came from a non-fertilized female.

Here's a pic: http://en.wikipedia.org/wiki/File:Heteropteryx_dilatata_0034b_L.D.jpg
 
  • #14
@emre: can you give an example? i can only think of all female populations....especially since asexual reproduction = clones.
Think of domesticated honeybees. The queen parthenogenetically lays drone eggs, while fertilised eggs are female.

Simultaneous hermaphrodites do not normally fertilise themselves, but may do so in the absence of a mating partner. I know that horseshoe crabs (which, however, are not crustacaeans) are sometimes hermaphrodites. I think parthenogenesis is the more probable theory, though. Parthenogenetical crayfish have been reported before, mostly in captivity. There is even a species in the pet trade which seems to be exclusively parthenogenetic. Check the following links:

Marmorkrebs

Crayfish Clones

At any rate, you have observed an interesting phenomenon. I suggest you separate as many babies as possible into individual tanks/containers, and keep the rest in a separate tank as a control group. And never, never release any of them! They are potential pests and habitat destroyers.
 
  • #16
Yeah, i get the crayfish partho, but all those crayfish are genetically identical, and all female....in the case of the rattlesnake, that is something is different that i totally dont get: rattler born from a VIRGIN snake is male. and there's no fertilization whatsoever, so it's different from bees...
 
  • #17
Yes, due to the invasiveness of certain crayfish we are not allowed to import any species of aquarium crayfish to my state. But they are still available, simply labeled as "freshwater lobsters" at all the aquarium shops...

Obviously I have no plans to release these land crabs to the Minnesota wilds. They will only be going to fellow hobbyists who have asked to be placed on a waiting list for the babies. Only a few people have them here at the moment so my goal with having them is a captive breeding program, not just to have it. I originally bought 5 extra pairs from a reptile breeder/author who did a one-time import for himself of this new red species after he had been having had success with breeding the Geosesarma bicolor (purple and yellow species). This red species does not behave in the same manner as the G. bicolor so things written about those "vampire crabs" are not exactly right for the reds but they are close. I have been meaning to do a write up for some time so the people who want Red babies from me can get their tanks setup and matured and know what to expect before I get ready to ship the first babies in spring/summer - provided I can catch the fast little buggers! LOL
 
  • #18
Yeah, i get the crayfish partho, but all those crayfish are genetically identical, and all female....in the case of the rattlesnake, that is something is different that i totally dont get: rattler born from a VIRGIN snake is male. and there's no fertilization whatsoever, so it's different from bees...
While domesticated honeybees do not start laying eggs before mating, fertilisation is not required at all. Since queen bees mate once in their lifetime, old queens eventually deplete their sperm store and start laying drone eggs only. (This leads to the collapse of the colony.) "False queens" display similar behaviour. When a queen dies suddenly and no queen larvae are present, a worker bee may start laying haploid eggs, just like an old queen. In this case, the false queen is technically and biologically a virgin. All parthenogenetic eggs are haploid males, while all fertilised eggs are diploid females. Workers and queens are only phenotypically different.

Parthenogenesis in snakes is very rare, as far as I know. Superficially, the process may resemble that of honeybees, i.e. only male offspring through virgin birth. The difference is quite subtle. What determines gender in honeybees is haploidity versus diploidity. This means that individuals with a single copy of their genome (haploids) are male, while individuals with two copies (diploids) are female. In snakes, what determines gender is the chromosomal W-Z system. This is very much like the X-Y system in humans, only reversed: males are homogametic, i.e. ZZ, while females are heterogametic, i.e. ZW. At least one copy of the chromosome Z is required for survival. So, why can virgin snakes only give birth to viable male offspring? Meiosis in females creates four haploid cells from a diploid somatic cell: three infertile polar bodies and one fertile egg cell. You may want to have a look at this chart to understand oogenesis:

Oogenesis

Since sex chromosomes are separated during the first meiotic division, both the egg cell and the secondary polar body will have the same sex chromosome. They are genetically identical, in fact, except for any homologous recombination that might have occurred earlier. (This recombination is the reason why virgin-born male snakes are not 100% genotypically identical to their mothers.) What happens afterwards is conjectural. We assume that the secondary polar body, which is genetically identical (again, except recombinated material) to the egg and in closest proximity, acts like a sperm and fertilises the egg cell, thus creating a diploid zygote which may or may not develop normally. Since both cells carry the same sex chromosome, the zygote will be either ZZ or WW. ZZ is a normal male, but WW is not a viable organism.
 
  • #19
I hope my scientific explanation didn't kill the thread! Looking forward to hear more.
 
  • #20
Well I guess there wasn't really anything more to add until these little ones are sexable and we'll see what the M/F ratio is if they aren't just all female. So I'll probably post an update on this possible Parthenogenic brood next February! LOL
 
Back
Top