Male and female growth rate.

[patsyking]

My two daughters and I have got mexican red knee slings. All the slings were the same size when bought, about 1cm. My one daughters has moulted twice since she bought it on 7th November, once on 10th December and again on 28th January and is now about 2.5cm. The other daughters has only moulted once after she bought it on 6th November and hers moulted on 17th December. I bought mine on 2nd January, again just 1cm and mine has'nt moulted yet. Im just wondering if males would moult more frequently because they mature quicker and don't live as long? Could mine be female as there has been no moult in three months and my other daughters too as hers hasn't moulted since December and the other one male having had two moults?

[Colin D Wilson]

Not quite as straight forward as sexual difference here Patsy.

The Factors to affect growth could be listed as

food availablity and frequency and type
variation in temperature
variation in humidity
stress levels (ie difference in tank setups/ hiding areas etc)
sexual growth rate difference
Daylight hours/lengths

You could have two spiders in virtually identical conditions, with an identical feeding regimen and the spiders could grow at different rates.

Take for instance one of my shelves, 9 identical tubs containing 9 H. sp.gigas from the same sac, same level of substrate originally, fed the same days, same level temp, humidity within accepted tolerances....i have a growth difference of 1.5 inch LS to 3 inch LS.

They're all very much individual at the end of the day

[Kate Arbon]

In my experience with my fairly small collection, frequency of moults is much more to do with temperature and feeding schedules. But my males seem to gain more size with each moult than my females, and thus reach mature size quicker but not necessarily in fewer moults.

I have placed a bet with myself on which of my 5 B. smithi slings are male and which are female based on their growth through the one moult they've had with me. Will be interesting to see if I got any of them right, lol.

[Stuart Baker]

I'm in the process of writing up my dissertation on this very subject. Across 80 B. vagans siblings over 11 months there was no significant difference between the sexes in moulting frequency or in the amount of growth with each moult. Temperature appeared to have a larger effect on these criteria than feeding regime, but I'd need to do more work on that before I was anywhere near convinced that wasn't an artifact. Hope this helps.

Stuart

[Colin D Wilson]

I'm sure there's others apart from me that would like to read the full results from this experiment when finished.
If you could offer these results here when you've submitted your dissertation, it would be muchly appreciated.

Colin

[patsyking]

Thanks everyone for your replies. I hope the result can be put on here too, I'd like to have a look.