Woodlice in damp conditions

[KatieB]

Hi! I've been searching the internet for detailed information about why woodlice prefer damp conditions. I understand it's to do with their exo-skeleton or how they breathe, but does anyone know (in detail), the science behind it? What happens if they are in dry conditions?
Thanks a lot

[Lance Morgan]

I'll have a stab!
Woodlice are crustaceans and need moisture to feed and breathe. Their shells are porous and by the process of diffusion they absorb water and oxygen and excrete waste in the form of gas (ammonia). They have two uropod at the rear and this is also used to absorb water when they are against moist surfaces in damp places. Woodlice lose water through their shells quickly and will dry out and die when there is no moisture because they have a large surface area to volume ratio and loose water quickly by diffusion. Their exoskeleton is not waterproof which means that they will also loose water through this.
Hope that helps

[zan]

Woodlice are isopods (crustaceans), not insects, that have evolved to inhabit some terrestrial environments. They therefore breathe through modified gills (not lungs) which must remain moist. For some species (if not all), they can only breathe the oxygen in air if it first dissolves in this fluid on the gills. As a result, woodlice cannot survive in dry conditions because they will suffocate.

...At least as far as I can tell! I've had a quick read through a couple of online scientific papers on the subject, and this seems to be the case for several species of woodlouse. Whether it's true for all of them I'm not sure.

[nightshade]

Originally Posted by KatieB

Hi! I've been searching the internet for detailed information about why woodlice prefer damp conditions. I understand it's to do with their exo-skeleton or how they breathe, but does anyone know (in detail), the science behind it? What happens if they are in dry conditions?
Thanks a lot

They look for damp conditions,usually in my garden,I now donate sheltered housing to Dysara crocata.
Woodlice are related to crabs and lobsters being crustaceans and their primative lungs need moisture

[zan]

ooh! just beaten to it! Having read Lance's response, I imagine it will be a combination of (at least) these two answers!

[Lance Morgan]

Hi Zan
yes interesting stuff. I believe they will also die if there is too much water i.e. they will drown if they are submerged in water.

[caladina]

woodlice have lungs underneath at the ars'e end

[zan]

yup - if I'm remembering right, underwater they would use their pleopods (on the abdominal segments) to fan water over the gills to increase water movement and help them breathe. Terrestrial isopods also have gills, not lungs, because they evolved from an aquatic habitat and invaded the land, so they are still restricted in that sense.

[ladyhawk]

they also secrete their urine through the skin as they do not have kidneys and other insects don,t like the taste ugh: good defense though

[caladina]

Originally Posted by ladyhawk

they also secrete their urine through the skin as they do not have kidneys and other insects don,t like the taste ugh: good defense though

that may explain the dipping motion i mentioned in another thread......woodlice behaviour Q