Sunday, March 19, 2006

Spider Poo


I was downstairs on the weekend weeding my pavers (frustration!) when I came upon this little pile of white dots. At first I looked up thinking a tiny bird has roosted above here - but of course it was a spider!

Spiders don't eat solid food - they inject/extrude digestive fluids over their prey to liquidise it before beginning a meal.

Special hairs around the spider's mouth filter the liquefied food as it is swallowed and prevent any solid fragments entering the pharynx and stomach. Both these organs are muscular and contractile and "pump" the liquid food into the gut. Beyond the sucking stomach as it is called, the mid gut branches off into the legs (yes legs), while the main tube of the gut passes through the narrow pedicel or waist into the abdomen. Here it is surrounded by a massive liver or digestive gland.

The excretory malpighian tubes (functioning like our kidneys) enter the gut behind the digestive gland. Just before the anus there is a large pouch which stores faecal material while reabsorbing water from it prior to defaecation.

Fecal excretions are coated or filled with guanine (a highly water-insoluble organic compound, containing five nitrogen atoms per molecule).

Under a spider's web you often find sucked-dry bugs cut free from the web by the spider while house cleaning. You may also find white dots, as I did, looking like paint spatters, 1.5mm to 3mm in diameter, often with dark centers - that is spider poo!

3 comments:

Otter said...

I love spiders too. I never pull down their webs cause I fiqure they will catch all the bad bugs and dispose of them for me. Which if you think about it is very kind of them.
I don't know what the name is but the ones that make the zipper type webs are very beautiful creatures.

pohanginapete said...

Judging from the relative sizes of your foot and those spots, either you have a very small foot or that's a fairly sizeable spider.

Very clear and well written post: thanks!

Ranger Cathy Mardell said...

I've got a big foot!