Tarantula Drumming

[Mark Harrison]

Does anyone know if whether a T drumming back at you indicates whether a T has reached sexual maturity or is just a way of signalling to other T's. A few days ago my Euathlus sp. Montane "drummed" back at me after i made a tapping noise over the other side of the room. I have tried to check the spider for signs of gender. These include...

1. Trying to judge the width of the T's opisthosoma, i was told to look to see whether it was wider at the pedicel and globose for a female and more ovoid and narrow at the pedicel for a male.

2. Checking for clubbed pedipalps, although they may be hidden under the extension of the cymbium i couldnt see any.

3. Looking at the epigynal plate for a small patch of bristles. At first i confused the bristles with the covering of the book lungs (newbie mistake)

4. Checking the area foward of the epigastric furrow, as apparently this protrudes above the surrounding area, giving the spider a "pot belly" for a female.

I also consulted Schultz & Schultz Tarantula guide for a more expert opinion and found only the above information. Having never seen a mature male/Female of this species most of what i have seen could be wrote of as conjecture.

[Phil Rea]

Personally I am not a great fan of ventrally sexing tarantulas, as despite understanding the principles and being entirely aware of how it is done, I don't believe it is a reliable method and is inherently prone to error for a great many species. Others will swear by it though, I'm sure.

The only absolutely certain way to know the gender of your spider is to view the inside of a moult, looking for the presence or absence of spermathecae and the uterus externus, or if it's a mature male, then it will have hardened emboli on the pedipalps which can be seen externally. Some species are also sexually dimorphic, in that maturing males and females are a different colour.

Males that are a moult away from maturity will sometimes have enlarged palps as the emboli develop internally, and this can often be noticed.

[Colin D Wilson]

Some spider species can be ventrally sexed as early as spiderling with more than a 95% success rate but as Phil has correctly said the only sure fire way is through examination of an exuvium.

I have noticed females of some Avicularia sp & Pocilotheria sp will slap their front legs in a drumming motion, these have been both juvenile and adult.

[Matthew Baines]

Our Shelf of juvenile old world arboreals is sometimes like having stomp tapping away and they all are different species and genus communicating with each other. I bet its like someone speaking Japanese to someone who doesn't .

[Lisa Baines]

yeah it is pretty mad to listen to, especially when the juvi P. striata and rufliata, get going... it's like listening to kids with a drum kit!

[Nicola Dolby]

Regarding the drumming, I have seen H. lividium adult females drum as a warning sign, their way of saying "go away I'm in a mood!". Mature males of all species drum too, maybe the little thing fancies you!