When you get your little jumping spider, you may be wondering if to pick a name for a boy or a girl. This can be difficult to tell as they might not show any signs of their sex yet. Some may keep you guessing; some may surprise you with a plot twist during their moult into maturity; others will be as clear as day. Let’s have a look at some of the ways you might be able to tell your spiders sex.
Chelicerae Colour:
Chelicerae are the shiny and brightly coloured fang coverings. It might seem very straightforward at first: pink and purple for a girl, blue and green for a boy. Unfortunately, it isn’t as simple as that. Certain Phidippus species share the same chelicerae colour regardless of sex, so it may not be apparent until they portray their dimorphic markings at maturity(basically their markings that show for sure if they are a girl or a boy). As Regius are my jumping spiders of choice, I’ll focus on them.
On the pictures above notice the beige mask of the female with pink chelicerae, the male is black with mostly green chelicerae, and glove like tips to his pedipalps when mature.
Most young Regius have dark gold, orange, or even slightly greenish gold chelicerae. It’s not easy to tell the sex with these colours. If their chelicerae turn pink or purple after a moult, you can be almost sure you have a female. However, if they go green, blue-green or stay gold, you still won’t know for sure as females can have these colours as well as males, and males can gain flashes of red in their green smile. The green is more common in mature females and young females who may change to pink in a later moult. In cases like this, you may want to use other traits to guess their sex, such as markings.
Markings: Most Regius have that little face of dots on their abdomen, but the colours of those marking might give their sex away. If the markings are pure white dots, black abdomen, and green chelicerae, you can assume you have a boy. Some females, however, will look very similar. I myself have a black female with a blue shine who has off-white spots; at first glance, she may look male, but her pink grin gives her away as female. Most orange, brown and tawny coloured spiders with pink or green chelicerae are female, but the odd sneaky male may slip past an untrained eye especially when their normal black areas are grey for the first 3 moults in your care. When you get to the grey and white Regius, things get really confusing as their markings can be practically identical. If they have pink or purple chelicera, you’re safe with the guess she is indeed a she; if they have green, you may want to look at their pedipalps.
The the above pictures you will notice the stark white markings on the male, yet the female is off white, peach and sometimes orange.
Pedipalps: These wiffly mustachio bits make a young jumping spider resemble the Lorax. In reality, these act as arms for your spider and are actually where you can find the male genitalia. Young spiders of both sexes can have a bushy, dense pair of pedipalps that may make seeing the colour of the chelicerae difficult, and as they age, the female will stay gloriously fluffy.
On a male nearing maturity, know as sub-adult, the pedipalps start to thin out and you will be able to see the chelicerae easily behind them, and the sub-adults will begin to look bulbous on the ends, this means they have one more moult until they are mature
Maturity:
This is the most confident way to sex your spider, but each jumping spider is different to when they mature. A spiders life stages are not measured in time such as days, weeks or months but in moults. Although ten moults is an average, your spider may reach maturity in fewer moults or more. You can’t use size to tell if a spider is mature as they also differ significantly, but here is what to look out for to know if your spider is mature:
Mature Male A mature male will look like he’s sporting a little pair of boxing gloves on the ends of his pedipalps, which are parted to show
off his blue/green chelicerae. He will also have slightly longer front legs perfect for dancing for his female.
Mature Female A mature female will have a clear, shiny spot on their underside. This is called an epigynum, and it may remind you of a belly button. If you can see this spot without squinting, you can be sure your spider is a mature female.
If you’re still unsure what sex your jumping spider is may want to pick a neutral name or accept that your spood doesn’t mind what you call them, as long as you like it.
