I saw my Avic flick and then go into a threat posture.

[Mojo Jojo]

I am writing this, because I was under the impression that members of Avicularia only possess Type II urticating hairs which have to be pressed onto the victim instead of being flicked onto the victim to be effective.

I have a 1" Avicularia sp. Peru Purple that had some debris stuck to one of its legs and it was clearly struggling to get free. When I was putting in a little bit of water into its vial to see if the debris would loosen from its leg, it managed to get out of the vial and ran onto my hand. After it apparently got tired of me trying to herd it back into its vial, it finally stopped running, flicked its butt with a leg and then threw up a classic threat posture.

With it being so small, I couldn't tell if any hairs went airborne or not, so I don't know if it was just expressing an an ineffective instinct or if it has another type of hair that can go airborne, in addition to its Type II hairs.

I mentioned the threat posture to illustrate that ANY tarantula, no matter how "docile" they are known to be can still be defensive when they feel threatened.

I should add that after it was in its extra moist vial for a few minutes, I did manage to get debris off its leg without injury.

 

[Zoltan]

I am writing this, because I was under the impression that members of Avicularia only possess Type II urticating hairs which have to be pressed onto the victim instead of being flicked onto the victim to be effective.

Generally true, but there is one proven and documented exception, and there have been reports of others.

Bertani, R., T. Boston, Y. Evenou & J. P. L. Guadanucci. 2003. Release of urticating hairs by Avicularia versicolor (Walckenaer, 1837) (Araneae, Theraphosidae). Bulletin of the British Arachnological Society 12 (9): 395-398.

Summary. The behaviour of releasing urticating hairs is described for the theraphosid spider Avicularia versicolor, a species endemic to the islands of Martinique, Guadeloupe and Dominica. In this species, the urticating hairs are thrown from the abdomen dorsum by movements of the tip of tarsus IV against the urticating hair field. Thus, it can be distinguished from other aviculariines, which transfer the urticating hairs through direct contact of the abdomen with the potential predator; instead, it approximates with theraphosines, which throw urticating hairs by using the spines on the ventral surface of metatarsus and tibia of leg IV to dislodge them. Morphological comparisons of typical urticating hairs of other aviculariines released by contact, airborne hairs of theraphosines, and airborne hairs of A. versicolor showed that, despite sharing their general morphology with other aviculariines, A. versicolor urticating hairs can be distinguished by the presence of well-developed barbs and their overall narrow shape. These characteristics approximate to those of airborne theraphosine urticating hairs. It is proposed that A. versicolor urticating hairs are derived from the typical urticating hairs released by contact found in other aviculariines and the characteristics that allow them to be airborne represent a homoplastic character shared with theraphosine species.

From:
Bertani, R., Boston, T., Evenou, Y., & Guadanucci, J. P. L. 2003. Release of urticating hairs by Avicularia versicolor (Walckenaer, 1837) (Araneae, Theraphosidae). Bulletin of the British Arachnological Society 12 (9): 395-398.

 

[Mojo Jojo]

Thanks bud. You are an asset to this community. :worship:

 

[Rue]

Cool! Thanks for the reference.