Bumble Bee snails definite opportunist.

[Jeff Hood]

With all the question about what these snails will do I decided to leave a couple of Astrea snails stranded, wich is very easy to do by the way.

I had two turned over on their sides ( incident caused by me cleaning the front glass, one on the sand and the other high up in the live rock. By day two they were both being eaten by at least two bumble bee snails, most likely alive. I qualify that because I did not see the snail move at all to right itself by that afternoon. There was no apparent struggle by the astrea snail. The bumble bee snails did not start feeding until day two.

If something eatable sits still long enough they will consume it. The shells are completly cleaned out. What the snails did not get the pods got the rest. I will add, I don't see any decrease in the number of pods by the number that are around my tank and my fat mandarin. They seem to be very good scavengers and if you are a snail you don't want to be caught on your back for very long 8O

Jeff

 

[liquid]

Yep, I've witnessed the same thing about 2 years ago. I was not happy when I found it out either (nor were my snails).

Shane

 

[Anonymous]

I keep these in large numbers in my tanks with other snails and I find they behave just like nassarius. Nassarius will converge on something dead or dieing.

I have never seen an astrea that fell off the glass do anything more than sit there upside down while trying to "right itself". The snails were more than likely on their way out and the bumble bees cleaned up the mess before it had a chance to foul up the water.

HTH

 

[Ryan22]

I've seen my nassarius do that also, when my conch died I think I had every nassarius in my tank on the thing. you can't say they don't do thier job. I still wonder how the species of snails that can't right themselves have survived. Everyday I have to put one or two upright again, if I miss one or I'm away for a day or so, I always find a couple of my nassarius cleaning out the shell.

 

[Desolas]

Mine do that as well, I find it very handy myself. I have a bunch of turbo snail shells scattered around my tank from old deaths, so it is hard to tell if one laying on it side is an empty - or a dead snail. When a turbo dies, it draws it's trap door in so it usually fouls before anything can really get to it. The bumble bee snails hone in on this and pretty soon I have 12 of them encircled around the dead snail like a beacon. I can pull the snail out and toss it before it fouls.

I've also only noticed they go after snails that have died because of flipping and they never bother the live ones. They are great to have in that respect, since Astea's that fall behind your rock work and out of sight will get cleaned up rather than them fouling.

 

[SPC]

Well, once again here is what Dr Ron says about this species of snail:

Hi Folks,

Engina species, including this one, are carnivores that subsist on eating carrion if necessary.

They are buccinid snails, and as such have a long proboscis that they can insert into clams, snails and worm tubes to rasp out the flesh of the prey. They likely secrete a poisonous "saliva" to immobilize their prey. Unlike the muricid snails, they do not have an "accessory boring organ." Consequently, they can not bore through calcareous substrata.

See this article for a discussion of predatory snails in general, but the article also shows the extension of the proboscis and feeding structures of a near relative of Engina that is found in temperate areas

They are preferentially predatory, that is to say they will eat living material in preference to scavenging food. If they do scavenge, they will preferentially scavenge carrion. Research on Engina species indicates, in nature, their diet preference is 1) worms, 2) snails, and 3) small clams. In a tank, there predatory activities may be obscured if 1) there are a lot of prey (such as worms) that are living in sediments (the hobbyist would simply not notice that they are being eaten, until the DSB started to fail) or a lot of snails. Additionally, as in all predatory snails of this nature, there are individual variations in dietary preferences, some individuals of the predator may prefer worms to snails, and vice versa. Interestingly, it turns out that they have to learn how to hunt, and will generally learn to eat the most abundant of their potential prey. Another point, though, they will always be predators.

Predators are not "found anywhere." Most predatory snails have both habitat and dietary preferences. The food for these more-or-less generalist predators would likely be found everywhere, and I suspect and differences in distribution would be due to other factors such as a prevalence of particular habitats or perhaps a differential distribution of their own predators. Also distributions vary through time. I have watched populations of some similar predatory snails, appear in an area, persist for about about 10 years, then vanish (in this case their predators became abundant), then after another 5 or 6 years reappear, presumably to start the cycles over.

As far as predators upon them in a reef system, I can't really suggest any that would be benign to other tank inhabitants. In nature, small buccinids are often eaten by small crabs, octopuses, sea stars, or some fishes.

Steve