Dubia and similar roach scavenging under water

[Xandri]

Hopefully I figure out how to upload pics from my phone but has anyone else experienced their roaches scavenging under water? I have dubia and another similar roach and they both do it. None have drowned. They have ways to get out of water but prefer to stay in or near it. Scavenging the food I feed my crayfish from the bottom. funny they sell crystals to keep your roaches from drowning. Below is a roach that I've been watching in the water all day.

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[Alex]

That is a cool observation how long have they been in the cage??

 

[windward]

funny they sell crystals to keep your roaches from drowning.

I think it's just a carry over from cricket keeping... and laziness. I use them too, so I admit to it. I also just pour water into their (shallow) dishes and let them figure it out. The tiny nymphs will drink from spray drops and the larger roaches climb right into the dishes.The reason the roaches can do this, easily, is that they can close their spiracles. This is why they can come up through plumbing, too...

I'm curious, though. What age groups do you see in the water? Do earlier instars venture in?

 

[Keith]

I've had a roach fall into water and appear bloated and dead. I put it in a dry cage and hours later it was alive and well. I've seen dubia nymphs go under water but never adults, as they went in tiny air bubbles were on them I think that is how they survived. Certain aquatic insects and spiders dive under water because the air bubble allows them to breathe, like humans scuba diving and oxygen tank allows us to breathe.

But all my roaches had accidental falls into water, yours you said went in on purpose, that is incredible! And it ate food underwater, I didn't think it was possible!

 

[windward]

The difference, though, is that aquatic insects have cuticular modifications that allows them to retain the air bubble against their spiracles (spiders rely on their silk). While all insect cuticles have some degree of water repelling properties due to the wax layer, and that will allow a bit of a temporary bubble, terrestrial insects tend to lack the modifications such as hydrofuge "hairs" (type of setae) or are able to make use of a subelytral cavity that would allow them to be truly aquatic.

Its still more likely that they're doing the equivalent of holding their breath. As for why roaches that appear to be drowned live when dried out - they can go a while without oxygen.

Surely most people here have done or seen the "drowned" fly and salt trick?

Does anyone know if there are any papers over the behavior and possible cuticular modifications of the semi aquatic roaches? I wonder if they actually qualify as aquatic at all or are really just exhibiting behavior that is present, to some degree, in many roaches?

 

[Keith]

American Cockroaches are great swimmers and live in sewers so I understand why they hardly drown. However for Dubia, they can't swim and natural habitat is not near water usually. I would like to know why these dubia chose to go in water. Setup looks more like for frogs, if it had wood chips and hiding places would they still choose to go in the water?

 

[Wolfie]

I've had a roach fall into water and appear bloated and dead. I put it in a dry cage and hours later it was alive and well. I've seen dubia nymphs go under water but never adults, as they went in tiny air bubbles were on them I think that is how they survived. Certain aquatic insects and spiders dive under water because the air bubble allows them to breathe, like humans scuba diving and oxygen tank allows us to breathe.

That's fascinating! Clearly these roaches have some kind of hydrophobic coating that allows them to maintain an air bubble like that, so, why don't they do this more? Or is it possible they would do it, but roach-keepers do everything to keep their charges out of the water, so they don't get a chance?