The purpose of feeding the H. lunulata to the O. scyllarus was part of a larger line of study examining coevolutionary arms races. In particular we are interested in how predator and prey interact and deal with various offensive and defensive morphologies and behaviors. The animals were not put together for our entertainment. I wanted to ask a fairly basic initial question - would a stomatopod that occurs sympatrically with a blue-ring attack it? We generally think that the coloration of blue-rings is aposomatic, but aside from people usually avoiding them because they recognize the blue-rings and have been told by other humans that they are dangerous, I know of no data that that demonstrate that the blue rings serve as a warning to any other species that might play the role of "predator". The next question to ask if there was avoidance would be whether this behavior was learned of innate? Similar research has been done on other aposomatic systems such as mot-mots and coral snakes, yellow-bellied sea snakes exposed to predatory fish or herons and egrets, etc. It has not been done with blue-rings. Making the question even more interesting from an evolutionary perspective is the fact that both H. lunulata and O. scyllarus have indeterminate growth so it is possible for their interactions to vary with different size relationships - large stomatopods might be able to kill and/or eat smaller blue-rings and large blue-rings might be able to prey of smaller stomatopod. This could considerably complicate the dynamics. It would seem more difficult for an innate avoidance to evolve under these circumstances or even possibly a learned one.
So where do you start exploring such a question. I would prefer to make my initial observations in the field watching blue-rings and stomatopods interact, but such observations are extremely difficult and even if you are persistent and patient enough to see a few encounters, you have little control over the participants, their size, physiology, motivation, experience, etc. Aside from those who are opposed to carnivores killing and eating prey, I assume most people would not object to this type of research. Bringing the animals into the laboratory gives us much more control over the interactions. First, I can control the predator making sure that it is hungry my depriving it of food for a specified period, making sure that it is not approaching a molt, etc. If it doesn't attack the octopus, I know that it is not simply avoiding the blue-ring because it isn't hungry. It is also easier to control the size relationship between the two and to assay the blue-ring to determine how much TTX it contains and/or delivers. (The former is done through chemical analysis; the later by giving the octopus a live grass shrimp, waiting a prescribed period after the initial attack, removing the shrimp and analyzing it to see how much TTX it contains.)
While the intereaction was staged, it was done in a very large tank (200 gal) with lots of rock into which the participants could escape. The stomatopod did have a pvc burrow, but it would have an even better one in the field.
When I presented the blue-ring to the stomatopod, I expected one of three outcomes. Most likely I thought, the stomatopod would flee or simply ignore the octopus. If so, I was interested to see if the blue-ring would also flee, do nothing, or attack (but these are different questions from what I was primarily interested in.) Alternatively, the stomatopod could attack driving off or killing the blue-ring. The third alternative, which I did not expect, was that the stomatopod would kill and eat the blue-ring.