woodlice behaviour Q

[caladina]

just a quicky on woodlice, why do they dip their rear ends downwards repeatedly at a rate of about one dip per second?
they seem to "flex" there last few segments at the rear, i dont think they are pooing , and when they do it they are not in contact or "in conversation" with other woodies

[zan]

Isopods (and other crustaceans) have uropods at their rear end, which can form a tail fan in some species. In the isopods, they are often 'antennae'-like structures. I can't find any definitive answer as to what their purpose is, but they are sometimes associated with secretory glands in the terrestrial isopods, so they may be 'scenting' in some way? They may also use them to feel the ground, or to detect 'scents' left by other woodlice... I'm guessing now, but I'll see if I can find anything more useful in work tomorrow. There are some proper isopod experts in this forum though - maybe they'll be able to help?

Zan

[hsl]

They are waving to each other.

TBH I have seen this only when it's wet outside so maybe they are just drying themselves off?

[Jason Green]

Yes, drying off is the most likely reason, but perhaps they lay scents as well?

[caladina]

might be a sent thing as i've seen them doing this while facing downwards on a branch, also while slowly moving fowards