Spiderlings Eating Healthy Adults in Holothele incei

[AbraxasComplex]

I've noticed in my colony of Holothele incei that my larger adults and juveniles had wounds on their abdomen. These scars I have witnessed the entire time I have kept this species. I have finally witnessed what is causing them.


The spiderlings are consuming the adults.



Yes, that's right. I keep feeding my colony a specific amount and through out the years would find an adult with tiny abdomen wounds that would eventually die. Even when I used super glue to seal the puncture area they passed on. Recently with an explosion of spiderlings from several females (4-5) as well as double clutches the result was an over abundance of spiderlings. In the past two months I have witnessed 3 large subadults-adults pass on due to puncture wounds. I personally thought it was an overly aggressive female though the wounds were too small.


Today I saw a spiderling crawl onto a large juvenile's back and bite. The juvenile did not react. In fact it continued to walk around as though nothing had happened. The same wound found on all the healed and dead incei was created. These are healthy juveniles and adults being bit.

I had witnessed in the past a large collection of spiderlings swarming a dying male, but never have I seen a healthy active subadult/adult be bit.

Theories on why the older tarantulas are not reacting?

 

[xhexdx]

No idea why, but I had something similar happen.

I had a female drop a sac and I decided to leave them with her once they hatched. At one point, I decided to rehouse them into a larger enclosure, and the female was gone. I figured she must have died and they consumed her, but it stands to reason that what you describe could have happened as well.

Maybe they're not quite as communal as we thought?

 

[AbraxasComplex]

They are still quite social and cannibalism does happen. Even in the most social arachnid species cannibalism is common. I think it's just an issue of the colony or group still enacting an opportunistic feeding regime. As the population increases greater sources of nutrients are needed. The pressure of a greater population probably increases the instinctual opportunistic feeding habits and that in turn leads to greater risks and bringing down larger, and in this case more familiar, prey items. A couple slings attack a large target, follow (which I witnessed), then wait for it to falter. I watched that one sling crawl off and follow the slowing juvenile, as it followed the dying one other slings started to lurk nearby, emerging from their burrows. They have just started to feed.


On another note concerning opportunistic feeding I have seen larger adult females and males consume the shredded carrots I put in there for the feeder items to munch on.

 

[Lorum]

That's something I haven't heard before...

Thank you for posting. Very interesting thread...

 

[Protectyaaaneck]

Interesting stuff. I had a small communal of h. incei myself (courtesy of Joe) that I ended up separating because they started eating each other.

Where's Fran and the gang, I thought they would be all over this.

 

[AbraxasComplex]

Well I have witnessed adults feeding on younger tarantulas every now and then. Usually it's an adult female eating a male, a male eating a spiderling, or two adult females sharing a third. Usually these feedings end up being a family affair as time progresses; the spiderlings swarm and devour the rest.

I won't deny that cannibalism occurs. I have always been open with that fact. This is just the first time I have witnessed spiderlings overcoming larger tarantulas.

This colony has lasted years and produced hundreds of tarantulas with at least 200 of various sizes being sold and sent out. On average the tank can support space for about 6 adult females, their numerous offspring, and several males. I only supply food for about 100 tarantulas. At this rate if cannibalism didn't occur I'd be overwhelmed with tarantulas and have an incredibly starved and unhealthy social experiment.


In time I will be doing a much larger tank and supply more food. This will allow territory for more adult females and allow a greater population to be supported with less nibbling.

 

[Bill S]

Maybe they're not quite as communal as we thought?

Even with communal species, there are population densities to take into consideration. In nature a given area will only support a certain size population, and different species of social animals have evolved different methods of controlling colony or population size. In the case of H. incei, there's no doubt an optimum size colony, beyond which there's a mechanism for either driving off or killing off excess individuals. Since our caging doesn't allow for excess individuals to be driven off, turning them into food seems a very productive alternative.

 

[AbraxasComplex]

Even with communal species, there are population densities to take into consideration. In nature a given area will only support a certain size population, and different species of social animals have evolved different methods of controlling colony or population size. In the case of H. incei, there's no doubt an optimum size colony, beyond which there's a mechanism for either driving off or killing off excess individuals. Since our caging doesn't allow for excess individuals to be driven off, turning them into food seems a very productive alternative.

I couldn't have said it better myself.

 

[AmbushArachnids]

What size tank are you using? If you were in the US id say send some of those extra slings my way so your not over run. Very interesting thread. Im glad you shared this important finding.

 

[Merfolk]

This behavior has been observed in higher animals, up to the house cats gnawing at their deceased "mother". When you see cannibalism occur even in mammals, no wonder it will occur among invertebrates.

 

[AbraxasComplex]

My tank is about 40 gallons with half of that being filled with piled, broken pieces of cork bark.

 

[RottweilExpress]

I've had numerous sacs in my colony, adn yet there's very few adults in there. I haven't seen what you've seen, but I've come across the same situation, dead females and juvies, sometimes killed from behind in the tunnels. I remember trying to pull out a dying female from her tunnel, but someone did hold on to her abdomen from behind, and very strongly at that. Another juvie had put her fangs in there and the female could do nothing about it.

I had a thread about the colony on a swedish forum. One of the interesting finds I made was that when I put the sac in there, I seperated 10-20 slings and put in salladcups beside the terra, and the rest, about 25 slings in the terra. In just 10 months, the next sac was hatched, which means from 2 instar or so, they were all mature and mating in 9 months. Then it's just kept spinning from that point. Also, important find is that the slings that were seperated were growing slower than the ones living communaly, about 25% slower at least. The ones in the cups got ruffly the same amount of food, and same temp as the ones in the colony, but were definetly not mature when the first sac was hatched. Huge difference. It also proved that the females were maturing far quicker than I thought, At roughly 3½ cm they were mating.