Thanks for the reply and agree with you on the above.
But we're working on some presentations for the public and trying to give factual information. For Metasepia pfefferi I have read some people online saying they are poisonous, others saying they are both poisonous and venomous and I'd like to get the facts straight when we do our presentation.
For the octopuses I am wondering if there has been any research done on this yet because as above, I want to have the correct info when giving presentations. I figured Tonmo was my best bet for getting accurate information.
For my two cents worth. As far as I can tell, Wunderpus and the Mimc are not venomous (although they may have a weak paralytic toxin used for consuming shellfish, this is common among octopus). Both of them imitate animals that ARE venomous, which make me think that they don't have any of their own.
I found evidence that said Metasepia are toxic, but it did not indicate to the extent. I would imagine that if they were lethal to humans, we would know, as they are a frequently studied cuttlefish species.
Hope this helps, at the very least you can highlight this is a gap in ceph-toxin knowledge that should be studied more in the future!
@GPO87 "As far as I can tell, Wunderpus and the Mimic are not venomous (although they may have a weak paralytic toxin used for consuming shellfish, this is common among octopus). Both of them imitate animals that ARE venomous, which make me think that they don't have any of their own.... I would imagine that if they were lethal to humans, we would know"
What is this based on? Nothing about their toxicity has come out in the literature that I can find. For all we've worked with them I don't know of anyone who has been bitten yet by Wonderpus, Mimic or Metasepia, so we really have no idea how humans react to their bites. Since Norman's mention of Metasepia's very high toxicity in a documentary many years ago, nothing has come out to futher explain the details. Also- most of the Metasepia work is done in aquaria with second+ generation individuals, not wild-caughts. It's completely possible these animals could be highly venomous in the wild but lose toxicity in aquaria over generations if some of the toxin is bacterial or from wild food. If you know of specific cases, please do share- they'd be really helpful to know about.
My point isn't that they are or aren't highly venomous. It's that we simply have no (available) information either way and it would be good to be cautious. Color patterns could just as easily argue for Mullerian mimicry (two toxic animals look alike) as they could for Batesian mimicry (non-toxic mimic looking like toxic model). A lack of information is by no means a green light that they're safe. I'd hate for someone to be bitten and get hurt because they acted based on a false sense of safety, especially in a remote area with limited access to medical care.
HI @Polpessa (thanks for the heads up! I'd forgotten your screen name)!! I get 3 weeks vacation/year starting in 2015! Which season do you suggest? I hope the diving is going great!!!
That's very true, I apologize if I made it sound like I was promoting them as a safe species, that was not my intent at all. I was merely making some observations based on some studies I reviewed (which I will admit also gave no concrete answer either way).
I completely agree that there is not enough evidence to make any sort of a concrete decision, and am always of the firm belief that people should be cautious about interacting with any non-domesticated animal, especially ones which may contain toxins of some kind.
I apologize if my assumptions came across too lax.
Thank you Mucktopus and GP087 for your replies.
It's frustrating that we know so little about these amazing animals.
So, if I understand correctly, for the octopuses nothing is known regarding their venom or toxicity on any animal, human or otherwise, correct?
Regarding Metasepia pfefferi, is it confirmed that the flesh is toxic? If so, to what extent? Would a human eating a small portion of certain parts of its flesh merely produce a reaction akin to eating 'fugu' in a Japanese restaurant or would you die? I understand that the possible effects of their venom on humans are unknown but do we know whether they have venom which is effective against shrimps and crabs for example?
Hi @Polpessa - Agreed- I wish we knew more. This is all I can find about Metasepia (in a paper about blue ringed octopuses):
"Other adult cephalopods, such as the flamboyant cuttlefish (Metasepia pfefferi) and the striped pyjama squid (Sepiolodia lineolata), are known to be toxic (Norman, M., pers. comm.). Additionally, an unnamed arm dropper octopus (Abdopus species 5) contains saxitoxin, which is functionally similar to TTX (Robertson et al., 2004)." in :
Williams, Becky L., et al. "Ontogeny of tetrodotoxin levels in blue-ringed octopuses: maternal investment and apparent independent production in offspring of Hapalochlaena lunulata." Journal of chemical ecology 37.1 (2011): 10-17. http://scholar.google.com/scholar?start=0&hl=en&as_sdt=0,5&cluster=11657146653907311519 (second link down should be a link to a pdf)
It would make sense if their skin were toxic to fish or stomatopods (L. lisa for example) since those could be big threats to the little waddling Metasepia, but I just don;t know of any evidence. If you see any attacks/spit-outs definitely post your observations!
@Polpessa, you might try @Danna to see if she has anything new since her Science 2.0 blog post. Note her long comment at the end of the original post. Not helpful to what you are trying to present but shows the difficulty of getting the information and pointing to studies that support it.
DWatley, thanks for the link to Danna's Science 2.0 blog post - I had in fact found that page as well. I will try contacting her to see if she has any updates if she doesn't post here.
Mucktopus, thank you for the quote from that paper on blue-rings. I have never witnessed anything trying to eat an adult flamboyant cuttlefish although I have seen both hermit crabs and some sort of sea-snail feeding on flamboyant cuttlefish eggs and wondered if they are not susceptible to the toxin or if the toxin in the eggs is just present in such small quantities as to not be dangerous to those animals? Or perhaps the snails and crabs later suffered ill-effects?
Someone diving here about 6 months ago filmed a scorpion fish which tried to eat a blue-ring and promptly spit it out, but then just today someone reported seeing a flounder eat a blue-ring and did not spit it out, despite 'prompting' from the dive guide.