Jump to content


Sow bugs, pill bugs, roly polies...


  • Please log in to reply
7 replies to this topic

#1 Guest_mrgrackle_*

Guest_mrgrackle_*
  • Guests

Posted 28 February 2008 - 08:18 PM

There are 8 types of terrestrial isopodes in n. america. Isopodes are the only class of crustaceans that have members that spend their entire life on land. Well, I've been trying to find free fish food... I read that sunfish eat crustaceans and then I remembered the roly polies where crustaceans (they have gills! it's why they're always in damp places.. if they don't have moisture they die). Being that they are crustaceans I thought they would have a lot of the same nutrients that other crustaceans have and if my sunfish eat crustaceans then they should be able to eat roly polies.... at least that's my thinking.

rjmtx mentioned some concerns like their shell and that it would be hard to digest. I've been thinking about this and I figured it wouldn't be any harder to digest then other crustaceans shells they would be eating. Also, fish are the main predetor of marine isopodes. I've been trying to find some nutrional value estimates for roly polies but I've been coming up short. I've found a place where someoen suggested that they'd be full of omega-3's because they're crustaceans. Somewhere else mentioned that their Calcium:Phosphorus ratio was 12:1 (which seems high from the little I know about calcium:phosphorus ratios). rjmtx also mentioned that they might hurt the fish from the inside, but from what I've read roly polies eat almost exclusively decaying organic matter. Rarely, they eat 'tender greens'. Supposidly they will eat just about any kind of decaying organic matter... which made me think that if I feed them certain vitamin/mineral rich foods I could work that up the food chain into my fish.

My fish seem to like them. I think at first they didn't know how to eat them but I think they're starting to figure out how to crush them up even when they roll up into a ball. Oh... roly polie trivia... there are 8 types of terrestrial isopodes in n. america... only 1 of them can roll into a ball, another type can roll into a "c". All the others look much like these two but can't roll up...

Anyone have an idea where I could find out the nutrional value of a roly poly, sow bug, woodlice, doodle bug, pill bug (they where perscribed for upset stomaches and they got their name because they rolled up into 'pills' maybe the high calcium content in their shells helps indigestion), cuffin cutter (!)

#2 Guest_Newt_*

Guest_Newt_*
  • Guests

Posted 28 February 2008 - 09:14 PM

There are a far greater number of freshwater isopod species; many of them are fairly easy to raise in captivity, if you want a steady supply of food for your fishes. The terrestrial ones can be raised easily as well.

I don't know of any resources that have the nutritional value of isopods laid out; of course the values would vary widely with the creatures' diet, soil and water chemistry, etc. I can tell you that the aquatic species tend to be a little softer and less heavily armored than terrestrial species.

#3 Guest_Irate Mormon_*

Guest_Irate Mormon_*
  • Guests

Posted 29 February 2008 - 12:19 AM

Interesting idea, MrGrackle. And thanks for the education - "Pillbugs", indeed! I'll have to try that sometime.

I never thought that any natives would eat 'em.

#4 Guest_Nightwing_*

Guest_Nightwing_*
  • Guests

Posted 29 February 2008 - 01:16 AM

To add to all of that..in a really hevily planted tank, some survive and even breed...and they are very cool little things on their own, particularly at night!(speaking of the aquatic species, of course!).

#5 Guest_mrgrackle_*

Guest_mrgrackle_*
  • Guests

Posted 29 February 2008 - 03:51 PM

To add to all of that..in a really hevily planted tank, some survive and even breed...and they are very cool little things on their own, particularly at night!(speaking of the aquatic species, of course!).


My sunfish have been eating them like crazy. Right now I've got a mix of sunfish from the colorado river here in austin. With help I've ID'd a redspotted sunfish, redbreasted sunfish, green sunfish... I don't think any bluegill (which is what I was really after). When I first started getting into the idea of raising native bluegill for food... all the sunfish looked like bluegill to me. I'm just going to keep them all in the stock tank and see which types do the best in the system I have.

I've embarked on raising terrestrial isopods. The ones I have the most of in my yard are the kind that can roll up into a ball (Cylisticus convexus).. or is that a "C" (Trachelipus rathkei) ... maybe I've got both kinds. Anyways, I took a styrofoam cooler, cut part of the top out and replaced it with some plastic so I can see inside the terrarium. I covered the bottom with a couple inches of topsoil and the covered most of that with a large piece of cardboard for the isopods to hide under, they don't like the light. I made the soil moist and give the inside of the terrarium a good misting every day. The terrarium isn't airtight but it's closed enough so that it stays humid but not suffocating. I believe the isopods want 50% humidity. They don't have the waxy body covering that insects have. That waxy coat lets insects live in just about any type of environment. On the other hand though, these isopods can take moisture straight out of the air.

I russled up a bunch of isopods and put them in the terrarium with a couple pieces of apple core. I checked on them this morning and they where all over the apple core and looks like they already ate some of it. I'm going to try some banana peel next since it's high in potassium and that's a mineral that aquaponic systems like I have (http://forum.nanfa.o...?showtopic=3972) become deficient in.

Fun stuff, I'll keep you all posted.

#6 Guest_KPW_*

Guest_KPW_*
  • Guests

Posted 02 March 2008 - 10:51 PM

I'd stop now before you do some serious damage.

Isopods are pretty successful for a variety of reasons. Perhaps the number reason is that they are resistant to high levels of pollution, particularly heavy metals, in their environment. You'll often find them where no other detritivores exist (earthworms etc.) because they can handle these high levels of toxins.

The way they do this is by storing the ingested toxins in their hepatopancreas. Given their short life span, they have no need to worry about this accumulation and simply "walling it off" inside is sufficient. One reason they are so numerous is because few things eat them. These toxins are passed on to your fish and will accumulate.

Scientists use them as indicators to test for heavy metal loads in soils and around former landfill sites etc.

I read this in middle school and didn't fully buy it. I went down to the creek and caught a Lepomis gulosus and a L. macrochirus (both less than 2 inches). The macrochirus refused them for weeks (despite being offered nothing else). The gulosus ate them from the start (big surprise, right?). Within about 6 months, the warmouth started to look tattered and sickly (holding fins to its sides, color light and pattern dull). I was convinced and stopped feeding them to him. Unfortunately, he never recovered and dies about 2 weeks later. Had the marochirus until I went to college.

Like others said, there are alot of other, natural and appropriate, foods you can raise for your fish.

Later, KW

Edited by KPW, 02 March 2008 - 10:55 PM.


#7 Guest_Newt_*

Guest_Newt_*
  • Guests

Posted 03 March 2008 - 10:39 AM

That's interesting stuff, KPW. I knew they were used as heavy metal indicators, but I didn't know they were such good bioaccumulators.

However, this sounds more like a reason to raise your own than to avoid them altogether. Additionally, while terrestrial isopods are avoided by many predators, aquatic isopods are eaten with gusto by nearly every animal I have offered them to, including pirate perch, juvenile turtles, and various aquatic salamanders, none of whom seemed to be the worse for wear (I have never used isopods as the primary diet, only as a supplement). They seem to be one of those organisms universally beloved by aquatics, along with chironomids and cladocerans.

#8 Guest_mrgrackle_*

Guest_mrgrackle_*
  • Guests

Posted 03 March 2008 - 12:52 PM

I'd stop now before you do some serious damage.

Isopods are pretty successful for a variety of reasons. Perhaps the number reason is that they are resistant to high levels of pollution, particularly heavy metals, in their environment. You'll often find them where no other detritivores exist (earthworms etc.) because they can handle these high levels of toxins.

The way they do this is by storing the ingested toxins in their hepatopancreas. Given their short life span, they have no need to worry about this accumulation and simply "walling it off" inside is sufficient. One reason they are so numerous is because few things eat them. These toxins are passed on to your fish and will accumulate.

Scientists use them as indicators to test for heavy metal loads in soils and around former landfill sites etc.

I read this in middle school and didn't fully buy it. I went down to the creek and caught a Lepomis gulosus and a L. macrochirus (both less than 2 inches). The macrochirus refused them for weeks (despite being offered nothing else). The gulosus ate them from the start (big surprise, right?). Within about 6 months, the warmouth started to look tattered and sickly (holding fins to its sides, color light and pattern dull). I was convinced and stopped feeding them to him. Unfortunately, he never recovered and dies about 2 weeks later. Had the marochirus until I went to college.

Like others said, there are alot of other, natural and appropriate, foods you can raise for your fish.

Later, KW



Thanks KW. I also read that same information, that they are used as bioindicators for heavy metal. This really bothered me because, not only am I feeding them to my fish, but I'm going to eat the fish. The isopods I've fed my fish have all come from my yard and seeing that my house was built in 1941 I know for a fact that there's lead based paint around the outside of the house and lead is THE heavy metal that I'd really have to look out for. Sure there's other ones that are 'worse'... mercury comes to mind, but mercury isn't found around peoples houses in any large quantity. I'm going to take the warnings and stop feeding my fish 'wild caught' isopods and I've started up two seperate isopod terrariums for the two species of isopods I've found in my yard. One is the very common slow moving 'roly poly' that can roll up into a ball. The other is a less armored, smaller, faster, flatter, lighter grey isopod.

Terrestrial isopods are consumed by starlings in pretty good numbers. There's a virus that effects terrestrial isopods called (something like) isopod irridescent virus. It makes the infected isopods lighter colored and makes them do things like wander out from their hiding spots. They get the virus from eating starling poop, then they get infected and offer themselves up to the startlings, who eat them and pass the virus through their poop to more isopods.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users