JenVegas
Arachnosquire
- Joined
- Aug 6, 2020
- Messages
- 64
So I've been really interested in sexual dimorphism recently, particularly how different it is in different species.
Some have obvious sexual dimorphism that you can see at a glance, others are much, much harder.
In some, the male is bigger. Others, the female is bigger. In some, the female is noticeably chunkier than the male, in others, they're the same size.
It's so interesting for me to scroll through a bunch of the old "sexing help" posts of different species. Because there's not always a ton of info out there.
And even after looking at the few pictures I could find, I still thought my first scorp was a male until someone here explained the difference to me.
So I'm wondering if we could make a thread that shows the sexual dimorphism of each species, to help people better determine the sex of their scorpions.
The only species I have experience with is one that has obvious sexual dimorphism, but even so, I was confused at first, so on the offchance someone else gets them and is also confused, I figured I'd write out the differences.
Centruroides Sculpturatus
Males are longer and thinner, while females are heavier and bulkier.
Males have long, thin, almost twiggy-looking tails, while females have shorter, slightly thicker tails. Males have slightly larger chela and pedipalps.
Males have longer, larger pectines, with a count between 20-35. Females have shorter pectines, with a count between 18 and 25. On males, you can often see the pectines sticking out from the sides, even when looking from the top down, but this isn't a guarantee.
Top: male
Bottom: female
Top: male
Bottom: female
Left: male
Right: female
Right: male, 24 pectines
Left: female, 21 pectines
Even though the number is similar, the male's pectines are noticeably larger and more pronounced.
Male on top, female on bottom
Male on left, female on right. Both have a visible pectine from the side, but it is much more pronounced on the male.
Same male and female, closer together.
Same male and female, resting in almost identical positions. Again, one of his pectines is visible, and the size difference in pedipalp/chela is more noticeable. Though he is longer, she is larger in terms of weight and bulk.
Tail length in males is long enough to easily reach forward without needing to bend or curl the body.
Tail length in females is shorter, and females often curl their bodies or raise the rear part of their abdomen to extend the telson and aculeus farther.
Behaviorally, males are faster, more agile, and more active. While I commonly see both males and females climb, males tend to be slightly better at it.
Females are slower and "lazier," but will often bask outside of their hide (ie, you see them more, while males tend to stay hidden). They are significantly more aggressive, and more eager feeders. I've noticed that males tend to be picky and shy eaters, while females often readily devour anything that moves.
I've seen a study showing that females of a similar species, C. Vittatus, are more likely to sting in defense than males. When threatened, males tend to use their superior agility and speed to escape, while females are more likely to stand and fight.
This has also been observed in C. Sculpturatus. Females are more likely to sting defensively, and their larger overall size and weight means that they inject more venom (though when adjusted for body weight, both males and females of C. Vittatus were found to inject similar amounts of venom).
Because this is a medically significant species, defensiveness and likelihood to sting may need to be taken into account. Though neither males nor females of this species should ever be handled.
Some have obvious sexual dimorphism that you can see at a glance, others are much, much harder.
In some, the male is bigger. Others, the female is bigger. In some, the female is noticeably chunkier than the male, in others, they're the same size.
It's so interesting for me to scroll through a bunch of the old "sexing help" posts of different species. Because there's not always a ton of info out there.
And even after looking at the few pictures I could find, I still thought my first scorp was a male until someone here explained the difference to me.
So I'm wondering if we could make a thread that shows the sexual dimorphism of each species, to help people better determine the sex of their scorpions.
The only species I have experience with is one that has obvious sexual dimorphism, but even so, I was confused at first, so on the offchance someone else gets them and is also confused, I figured I'd write out the differences.
Centruroides Sculpturatus
Males are longer and thinner, while females are heavier and bulkier.
Males have long, thin, almost twiggy-looking tails, while females have shorter, slightly thicker tails. Males have slightly larger chela and pedipalps.
Males have longer, larger pectines, with a count between 20-35. Females have shorter pectines, with a count between 18 and 25. On males, you can often see the pectines sticking out from the sides, even when looking from the top down, but this isn't a guarantee.
Top: male
Bottom: female
Top: male
Bottom: female
Left: male
Right: female
Right: male, 24 pectines
Left: female, 21 pectines
Even though the number is similar, the male's pectines are noticeably larger and more pronounced.
Male on top, female on bottom
Male on left, female on right. Both have a visible pectine from the side, but it is much more pronounced on the male.
Same male and female, closer together.
Same male and female, resting in almost identical positions. Again, one of his pectines is visible, and the size difference in pedipalp/chela is more noticeable. Though he is longer, she is larger in terms of weight and bulk.
Tail length in males is long enough to easily reach forward without needing to bend or curl the body.
Tail length in females is shorter, and females often curl their bodies or raise the rear part of their abdomen to extend the telson and aculeus farther.
Behaviorally, males are faster, more agile, and more active. While I commonly see both males and females climb, males tend to be slightly better at it.
Females are slower and "lazier," but will often bask outside of their hide (ie, you see them more, while males tend to stay hidden). They are significantly more aggressive, and more eager feeders. I've noticed that males tend to be picky and shy eaters, while females often readily devour anything that moves.
I've seen a study showing that females of a similar species, C. Vittatus, are more likely to sting in defense than males. When threatened, males tend to use their superior agility and speed to escape, while females are more likely to stand and fight.
This has also been observed in C. Sculpturatus. Females are more likely to sting defensively, and their larger overall size and weight means that they inject more venom (though when adjusted for body weight, both males and females of C. Vittatus were found to inject similar amounts of venom).
Because this is a medically significant species, defensiveness and likelihood to sting may need to be taken into account. Though neither males nor females of this species should ever be handled.
it would look like a millipede...only cooler!
