Unusually Small Mature Male

[Fallimsa]

I have just realised that my Chilobrachys sp. Kaeng Krachan is a mature male after about 4 months since he moulted! I always thought his pedipalps looked like a MMs and he has been very active and refusing food but the thing is... he is only 3 inches at the most! Is this normal? I know females are usually 6-7 inches of this species so it never crossed my mind that he would be mature until it just hit me when I was looking at him...

 

[advan]

Yes, it's normal.

 

[RezonantVoid]

A few weeks back my Phlogius Strennus matured into a male. The time it took from sling to mature was only 14 months and he's crazy small. It can happen sometimes but is likely nothing to worry about

 

[EtienneN]

Yeah the MM P. subfusca I traded last weekend was pretty small, like a 5 inch leg span with a super tiny abdomen. He ate well after he matured and it never grew any bigger, maybe like literally half an inch long. However, small MMs can still get the job done.

 

[korg]

It's an evolutionary advantage for males to mature at a variety of sizes... it creates a larger window of available mature males.

 

[MikeC]

That’s a pretty big size difference!
Kinda want to see a mating pair now.

 

[cold blood]

It's an evolutionary advantage for males to mature at a variety of sizes... it creates a larger window of available mature males.

Well, small males very often arent maturing any faster than their brothers.

 

[korg]

Well, small males very often arent maturing any faster than their brothers.

It would certainly be interesting to see if there's any correlation between mature size and growth rate (for males and females!)... I imagine with a large enough sample size one could find small and slow growing specimens and large, quick growers. I don't feel like I've ever raised any "unusually" small males so can't really say personally on that front. I thought it worth mentioning because I've read that before and it seemed to make sense! Even a bit of difference in maturation rate could push a male over into maturing during the next season, etc.

 

[cold blood]

Smaller than average males do tend to grow slower, and put on a lot less growth per molt. They all will mature with the same number of molts.

 

[advan]

Well, small males very often arent maturing any faster than their brothers.

Not all the time. See the quote below.

It may be directly related to an adaption to a hazardous environment, firstly the two maturation stages for males of this species (small males mature quickly and may avoid greater risk of bushfire, flooding, etc...while the bigger males provide the opportunity for "premium" breeding), and, the big males may travel much farther than their smaller counterparts and live longer if they live to maturity. It's like a breeding insurance policy for the wild populations. One clutch can still provide fertile males even 2 years into their life cycle, thus possibly skipping floods etc that could wipe out the bigger males that have yet to mature. This seems to be the case in captivity anyway. So, I'd see it as an adaption to the environment, and the slow down in size growth from breeding may also be a direct result of living in a hazardous environment too (but to really hypothesize that decently would require some pretty heavy work in the field).

Steve

 

[korg]

Not all the time. See the quote below.

Yes, what Steve said!