Some Australian Huntsmen

[Staehilomyces]

Holconia nigrigularis:


Isopeda woodwardi


Neosparassus magareyi


Isopeda magna


CB Isopeda vasta next to a recent molt


Isopedella leai

 

[rock]

Shh. These species are not great for handling

 

[Staehilomyces]

Shh. These species are not great for handling

Their venom is extremely mild, they're super reluctant to bite, and unlike some other huntsmen like Heteropoda, they aren't very prone to bolting either.

 

[RodG]

Love this group of spiders!

 

[Arthroverts]

Beautiful specimens! Kind of envious they are so easy to manage in comparison to Heteropoda and the like.

How are the Zachria doing?

Thanks,

Arthroverts

 

[The Snark]

and unlike some other huntsmen like Heteropoda, they aren't very prone to bolting either.

Could you explain - go into details, on why this is? Product of environment seems likely. Any other factors?

 

[Staehilomyces]

Beautiful specimens! Kind of envious they are so easy to manage in comparison to Heteropoda and the like.

How are the Zachria doing?

Thanks,

Arthroverts

The Zachria are fine for the most part, although the one that arrived injured did end up dying. They're fussy eaters, but they still take food. Just nowhere near as voraciously as the other huntsmen do.

 

[Staehilomyces]

Could you explain - go into details, on why this is? Product of environment seems likely. Any other factors?

I don't know why to be honest, but they just seem more laid back. They can still run really fast if you freak them out, but they don't teleoprt like Heteropoda. In general, they move at a comparable speed to tarantulas.

 

[The Snark]

I don't know why to be honest, but they just seem more laid back.

Most interesting. Since Venatoria the world over are light speed, environments seem highly unlikely. Thus genetics is the likely factor. A different branch of sparassidae and going by the general rule regarding Aus fauna, likely a much older genus.
(Got to love Aus in that regard. Several centuries in most locales of the world where Aus evolutionary adaptation gets counted in dozens of eons.)

 

[Dabugboi]

Why evolve to be one of the fastest groups of spiders to use biting as a defence mechanism? Weak venom, flexible fangs, not going to do much damage. Huntsman's inhabit trees or rocks with tight crevices, with superb mobility and a flat body it would be much more efficient to save venom for prey and simply hide form any threat. Further, the genus that tends to inhabit bushes rather than trees (Neosparassus) have a bulbous head likely containing larger venom glands, a somewhat more intense temperament and an elaborate threat posture are clearly adapted for intimidation of predators, as bushes do not provide much shelter and the stocky build of Neosparassus males them slower.

 

[The Snark]

Why evolve to be one of the fastest groups of spiders to use biting as a defence mechanism?

With Venatoria this seems to be the case. But there are so many factors involved we would be wrong to assume certain rules apply across the board. A vast world unto it's own that would leave Sherlock Holmes on his best day perplexed and confused.
Take Phoneutria. Very similar in build and physique to sparassids. Some with exceptionally powerful venom, some quite mild.
I'm a little more familiar with snakes. A green pit viper here in Thailand, definitely an Olympic sprinter with a very powerful venom. Compare to Kraits - on the whole slow and laconic in the top 5 most lethal venoms. Compare them to the king cobra, both opheophagus, O Hannah a marathon runner with venom not even in the top 50 in toxicity.
Evolution in varying environments, climates, ecosystems, differences in available prey. And variables within a single species. Russells and one or more keelbacks, the venom differs depending on prevalent environment conditions. In hotter climes the predominant venom is a hemotoxin, colder climes more neurotoxin.

But coming back to Venatoria, I've never seen a threat display. I suspect a mom packing an egg sack might make one but it would be meaningless since her chelicerae are clamped to the egg sac.

 

[Staehilomyces]

Most interesting. Since Venatoria the world over are light speed, environments seem highly unlikely. Thus genetics is the likely factor. A different branch of sparassidae and going by the general rule regarding Aus fauna, likely a much older genus.
(Got to love Aus in that regard. Several centuries in most locales of the world where Aus evolutionary adaptation gets counted in dozens of eons.)

I think it's more genus/species related than locale. The Heteropoda we have here in Australia are super bolty, just like their overseas counterparts, and I generally avoid handling them unless relocating one from a human dwelling (they're easily the most common huntsmen in urban areas here). Pediana and Yiinthi are also lightning-quick and very nervous, so I don't handle those either. It's mainly ones from the Deleninae subfamily (Holconia, Isopeda, Isopedella, Typostola, Beregama, Neosparassus etc.) that are more laid back, especially as adults.

 

[Staehilomyces]

A couple pairings:

Isopedella leai:
\

Neosparassus magareyi; they mated not long after this photo was taken.