I didn’t know the answer, so asked one of the authors. The short answer is that they are significantly harder to detect using visualization techniques and sequencing the genome is just a lot easier, and requires way fewer insects to do so.
The longer answer is that the way we’d “see” these ion channels in insects is basically creating a fluorescent dye with a molecule that binds to only the specific ion channel you were trying to measure (e.g. cold detection might be different from mechanical injury). Then, you’d take many cross sections of the insect’s body, and hope that one of them intersected with the dyed molecule in the right position in the nociceptor. You’d have to come up with individual molecules that bind with each kind of nociceptor you were trying to detect, and not other ones. Also, there is a strong chance this doesn’t work, so you’d have to do it on many different insects and hope that one produces a good result.
It sounds like for smaller insects, there are some other techniques that allow you to more directly look at these proteins, but mantid bodies are too large for them to work. And, even if looking at them directly, you’re looking at them in a densely clustered surface with moving parts (animal tissue), and hundreds or thousands of other proteins, etc, so it wouldn’t necessarily be easy to differentiate them.
But, sequencing and assembling a genome of an insect is fairly easy—you theoretically only need one individual (though in practice it might be more), and the rest of the process is fairly straightforward and reliable.
Thanks for writing this up! Dumb question: why can’t you just directly see if mantids have nociceptors? Are they hard to detect?
I didn’t know the answer, so asked one of the authors. The short answer is that they are significantly harder to detect using visualization techniques and sequencing the genome is just a lot easier, and requires way fewer insects to do so.
The longer answer is that the way we’d “see” these ion channels in insects is basically creating a fluorescent dye with a molecule that binds to only the specific ion channel you were trying to measure (e.g. cold detection might be different from mechanical injury). Then, you’d take many cross sections of the insect’s body, and hope that one of them intersected with the dyed molecule in the right position in the nociceptor. You’d have to come up with individual molecules that bind with each kind of nociceptor you were trying to detect, and not other ones. Also, there is a strong chance this doesn’t work, so you’d have to do it on many different insects and hope that one produces a good result.
It sounds like for smaller insects, there are some other techniques that allow you to more directly look at these proteins, but mantid bodies are too large for them to work. And, even if looking at them directly, you’re looking at them in a densely clustered surface with moving parts (animal tissue), and hundreds or thousands of other proteins, etc, so it wouldn’t necessarily be easy to differentiate them.
But, sequencing and assembling a genome of an insect is fairly easy—you theoretically only need one individual (though in practice it might be more), and the rest of the process is fairly straightforward and reliable.