07 June 2007

Fly away birds, here come the isopods

The main function of the bird bath in our backyard is to provide water for the neighborhood birds. But birds are not the only animals that utilize the bath. I have already written about the very abundant bdelloid rotifers that live in the water. The other nite I witnessed another group of animals apparently partaking of the water that was being offered. They were isopods.

isopods@birdbath1
In this and the next photo the red dotted lines mark the approximate position of the top of the water.

What were the isopods doing in the bird bath? It had rained earlier and at that time (this was around 2130 hours) the ground, the grass and all the other plants were wet. If the isopods needed water, they certainly didn't need to climb all the way up to the bath, which is 60-70 cm above the ground. Moreover, how did they know that there was water up there?

isopods@birdbath2

Terrestrial isopods evolved from marine ancestors (more on isopod evolution here). So I thought maybe they were reenacting the emerging of their aquatic ancestors out of the sea onto the dry land millions of years ago. But later when I saw the next picture, I changed my mind. I think they just like to look at their own reflections in the water.

isopod@birdbath3

7 comments:

clare said...

How do they know? This is something that has always interested me. I remember getting my pupils to do that classic experiment with a petri dish divided into four - two dry and two dark so you end up with 4 different environments. I was always impressed with this because it was the one biological experiments that seemed to consistently work - most of the wood lice always end up in the damp and dark. But is it the result random wanderings, or can they sense the drak and damp from afar?

Deniz said...

Isopods? That's what they're called! I just call them tespi bocekleri or tespis :-)

AYDIN ÖRSTAN said...

They have many other names, including, roly-polies, woodlice, pillbugs, sowbugs.

It's "tespih", by the way.

Deniz said...

woodlice? that's what woodlice are??? but they're so cute!

biosparite said...

Please add "doodlebugs" to the list of common names. a friend of mine who grew up in Houston reports staging doodlebug races when she was a little girl. The contestants were placed on a piece of paper or the sidewalk at the center of a circle drawn in apprpriate media for the substrate and turned loose to head for the nearest shelter.

Michaelangeloh said...

What about the green ring around the bowl?Would it hold microscopic nutrients that were growing again due to the water and they perhaps drawn to the matter?

AYDIN ÖRSTAN said...

The green ring around the bowl is our old friends (and relatives) cyanobacteria. Do I have to collect isopod poop now?