Environmental manipulation and breeding in captive Tarantulas

[Frogdaddy]

In situ, there are a breeding season for them, and and tmk, they respect these periods, even males tend to mature in the right time and get out of their hides to find a female in these periods.

That said, I agree with Cold Blood, in captivity, most species can drop a sac whenever the season we are. I've also experienced some species laying eggsacs in autumn/winter and they hatched "perfectly", even tropical ones.

I think high altitude species (and a few others too) like Bistriopelma, for example, require more attention/care and are harder to breed due to air pressure and even temperature, as have been said in this thread already.

Just want to point out that temperature in the t room, in autumn/winter, never drops more than 18C, at the worst days. Overall, it stays in about 20C-22C. Also, there's a photo period simulated by led lights, and I use to moist the enclosures more often in dryer seasons.

Only thing I will disagree with Cold Blood and others, and its pointless to continue arguing about, is towards humidity. Just will point this out, though, I'm not made of glass so, I couldn't care less wether one find humidity laughable or not, however, others can take this words as an offense. So, I'd be careful not be disrespectiful when disagreements come up.

Other than that, I don't believe breeding and enviromental seasons is a must, at least to most of tarantulas species, but to a few, it should be taken into consideration.

That's all folks. Hehe.

Perhaps using a small 1/4 hp aquarium chiller to cool temps? Bistriopelma are a montane dwelling spider correct?
I saw the paper from May 2020 describing two new species in this Genus. A NW with a horn, pretty cool.

 

[DomGom TheFather]

All hail substrate!

The problem with the word humidity is two fold. First, it falsely alters the focus of the keeper (from the sub to the enclosure's air). Second, it has people believing that the humidity in the enclosure matters, when its like 2% of the air in the enclosure that actually matters, that's the thin layer that develops just above the damp sub....since this thin layer is what matters (to keep the book lungs functioning properly), and its provided for by damp substrate, and not the enclosure or room's ambient humidity, it seems pointless to even talk about humidity, when the dampness of the substrate is all that matters. Saying a t needs damp sub simplifies things. The biggest issue most people have is over-complicating otherwise simple things...the word humidity is probably one of the most over thought things for many newer keepers thanks to care sheets.

For substrate provides.

 

[The dragon slayer]

I'd like to ask if any of you breeders out there has had a female that has taken an extremely long time to drop a sac (as in much longer than would be normally expected), and what your theory is for the reasons, i.e. lack of the correct environmental cues etc.

It's not unknown for females to take up to a year to drop a sac - even if environmental conditions are perfect this matters little unless for example you've sent off your own female for breeding as it's likely you may be waiting a couple of years before you get it back if at all...
Some people do take extra care and 'condition' the females by cooling them off for several months but there's no perfect calculation from my understanding

 

[Matt Man]

I have heard through my various connections that Grammostola for whatever reason seem to struggle with the flipping of seasons from Southern to Northern Hemisphere. People are having success breeding them I am guessing it is less important than I have heard. I learned from the one person I know who seems to successfully breed C Cyanopubescens with regularity that a 'mock flood' in the enclosure of the female T makes breeding them easier. We have 2 species of Aphonopelma here in San Diego, Eutylenum and Steindachneri and right now male Steindachneri are on the march, unless we are getting an early run on Eutylenum which usually show up a bit later. This season has been weird, early showings of the various orb weavers as well

 

[StampFan]

Barometric pressure is also a factor and we can't do anything to manipulate that. Unfortunately, we don't have enough information to say how much of a role barometric pressure plays, but it does play a role along with temperatures and rainy seasons. How much of a role it plays might also differ from place to place and could account for why some species from a particular country/region are more difficult to get egg sacs from in captivity than others.

I'm pretty sure the barometric pressure also affects molts; in a larger collection they seem to come in bunches for whatever reason. My experience anyways, as its the only reasonable explanation.

 

[Frogdaddy]

I'm pretty sure the barometric pressure also affects molts; in a larger collection they seem to come in bunches for whatever reason. My experience anyways, as its the only reasonable explanation.

Unless there is a "molt pheromone" for lack of a better term.
Edit: I don't put a lot of stock in barometric pressure as an environmental factor for breeding. Barometric pressure is always in flux up or down bit It's a pretty steady value world wide. As a general rule at sea level barometric pressure is usually about 29.9 inHG. There are exceptions that lower pressure like a hurricane or typhoon.

 

[DaveM]

Unless there is a "molt pheromone" for lack of a better term.

Well there is! Sort of, probably, I think.

There is a molting hormone: ecdysone, that also regulates the production of cuticular hydrocarbons (CHCs), which act as pheromones (in insects, probably in spiders too).
Fun fact: ecdysone metabolism/breakdown is regulated by a steroid dehydrogenase/reductase enzyme called spidey <-- not joking, that's really its name!
Overexpressing or knocking down spidey disrupts pheromone signaling. This is in insects, but these pathways are so well-conserved that it's probably exactly the same in spiders. In fact, it's almost the same in us. We humans have hormones very similar to ecdysone, and you may have heard of them: testosterone and estrogen.
And we have families of enzymes very similar to spidey: the 17-beta-hydroxysteroid dehydrogenases (HSD17Bs) and the hydroxysteroid dehydrogenase-like proteins (HSDLs).

So see: all of us living creatures, we are not so different after all!

P.S. Who knows about barometric pressure? I'm not discounting it either. But you know, you people that try to control every parameter of the environment, you must agree that it makes you conniving and manipulative people!

 

[Frogdaddy]

If there any keepers in Texas/Louisiana, Arkansas, please stay safe. If you're safe and also in the path of the remnants of Laura over the next 5 days, please keep an eye on your T's and report any unusual behavior. Even after the storm is downgraded to a tropical storm and then tropical depression there will still be a sizeable drop in barometric pressure associated with this system.
If there is any correlation with breeding activities or T behavior in general and a change in barometric pressure this would be an opportune time to report your observations. Stay safe all.

This is an older article but still interesting on how UV light effects spider mating.

Strange but True: Spiders Need UV Light to Feel Amorous

Forget turning out the lights to give jumping spiders privacy for mating

www.scientificamerican.com