Urticating setae.

I used a Bresser microscope with a Pc-ocular for all the pictures.

I collected the urticating setae from my 5 year old Brachypelma smithi females abdomen using a small paintbrush – she is very generous when it comes to urticating setae. Even though I got the setae from her abdomen I still got a trichobothrium in my sample. The trichobothrium can be seen to the right of picture M2.

Picture M1 is with 16X9 magnifications.

Picture M2 and M3 I used 16X40 magnifications.

All 3 pictures show the type III of urticating setae and they are about 0.7 mm in length.

On picture M2 you can see a type III urticating setae and to the right a trichobothrium. The trichobothrium is located near the eyes of the Brachypelma smithi. The tarantula use trichobothriums to get an idea of what’s going on in the surroundings.

The trichobothrium can detect movement in the air and thereby tell the tarantula if a prey is approaching.

Picture M3: Seeing an urticating setae under a microscope it is easy to understand why they can cause so much irritation and be a danger for the eyes.

/Falck