# How to determine if a Jumper is an adult?



## MrZorak (May 17, 2020)

Hi everyone, newbie here. I have recently taken in some species and I was wondering how I can best determine if they are adult. For purposes if this discussion I will be talking about Bronze Jumpers (Eris militaris) in particular as well as Bold Jumpers (Phidippus audax). 

Are there any key things to look out for with these species? For example, I have two female Bronze jumpers. One is a bit smaller and less fat. The other is far more rotund and that makes me suspect they will be able to lay eggs soon. 

For Bold Jumpers, is it that they are only true adults when they get their green/blue palps? Any information you can provide would be appreciated!


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## Lucky123 (May 18, 2020)

MrZorak said:


> Hi everyone, newbie here. I have recently taken in some species and I was wondering how I can best determine if they are adult. For purposes if this discussion I will be talking about Bronze Jumpers (Eris militaris) in particular as well as Bold Jumpers (Phidippus audax).
> 
> Are there any key things to look out for with these species? For example, I have two female Bronze jumpers. One is a bit smaller and less fat. The other is far more rotund and that makes me suspect they will be able to lay eggs soon.
> 
> For Bold Jumpers, is it that they are only true adults when they get their green/blue palps? Any information you can provide would be appreciated!


Don’t really know about E. militaris, but for P. audax I think you are talking about the chelicerae (the palps are what they use to hold stuff) for mature male P. audax they have big fuzzy arms with white stripes. With both sexes of P. audax generally the juvenile’s have orange markings on their backs, while when mature it changes to white. Although in some regions such as Florida their are exceptions and they stay orange for their entire lives. Hope you found this information helpful!
Here is a picture of my juevinile P. audax most likely 4th instar, the green parts above the fangs are chelicerae

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## MrZorak (May 18, 2020)

Lucky123 said:


> Don’t really know about E. militaris, but for P. audax I think you are talking about the chelicerae (the palps are what they use to hold stuff) for mature male P. audax they have big fuzzy arms with white stripes. With both sexes of P. audax generally the juvenile’s have orange markings on their backs, while when mature it changes to white. Although in some regions such as Florida their are exceptions and they stay orange for their entire lives. Hope you found this information helpful!
> Here is a picture of my juevinile P. audax most likely 4th instar, the green parts above the fangs are chelicerae
> View attachment 345020





Lucky123 said:


> Don’t really know about E. militaris, but for P. audax I think you are talking about the chelicerae (the palps are what they use to hold stuff) for mature male P. audax they have big fuzzy arms with white stripes. With both sexes of P. audax generally the juvenile’s have orange markings on their backs, while when mature it changes to white. Although in some regions such as Florida their are exceptions and they stay orange for their entire lives. Hope you found this information helpful!
> Here is a picture of my juevinile P. audax most likely 4th instar, the green parts above the fangs are chelicerae
> View attachment 345020


Yes I meant chelicerae. Still very much learning here! 

My P. audax male didn't have visible green chelicerae when at the phase where his back had orange. Do you know if there are any other indicators for adulthood? It would confuse me a lot of I ended up having one with orange that PERSISTED with that coloration, especially for the females who would then look similar between subadult and adult. I am used to the cut and dry aspect of sexing and determining age for mantids!


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## Lucky123 (May 18, 2020)

MrZorak said:


> Yes I meant chelicerae. Still very much learning here!
> 
> My P. audax male didn't have visible green chelicerae when at the phase where his back had orange. Do you know if there are any other indicators for adulthood? It would confuse me a lot of I ended up having one with orange that PERSISTED with that coloration, especially for the females who would then look similar between subadult and adult. I am used to the cut and dry aspect of sexing and determining age for mantids!


With the chelicerae on juveniles it can be hard to see. Do you no what instar it is (how many molts is has had)? They generally live to molt about 5-6 times, in a span of 6 months to a year. For captive breed spiders it is easy to keep track but for wild caught ones I use the process of elimination. 5th instar is usually considered mature, on their last molt they lose the ability to stick to plastic/glass, so if it can still climb glass it is not senior, if it is still orange then that eliminates 5th instar, so it could be 1st 2nd 3rd or 4th. 1st would be really tiny (around 3mm), and 2nd would be about the size of a Salticus scenicus, 3rd would larger and closer to the size of an adult female Habronatus pyrithrix. 4th is close to adult size about the size of your pinky finger. I apologize if you don’t understand, I was just using some of the wild species of jumping spider that I see a lot. So hopefully this will help you rule out the maturity, front legs that are fuzzy and longer than the rest means a mature male, females will also get quite a bit fuzzier and generally the spots turn white, for most of their life they have iridescent chelicerae, but it is hard to notice until the fangs get big.

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## MrZorak (May 18, 2020)

Oh no you are making sense, don't worry. I keep mantids, so I know instars, just very new to jumpers. I also have a Salticus scenicus so that comparison works for me! I didn't know they lose capacity to climb smoother surfaces as adults. 

I do not know which instar, since all are wild caught. Thanks for the feedback, this helps!


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## Lucky123 (May 18, 2020)

MrZorak said:


> Oh no you are making sense, don't worry. I keep mantids, so I know instars, just very new to jumpers. I also have a Salticus scenicus so that comparison works for me! I didn't know they lose capacity to climb smoother surfaces as adults.
> 
> I do not know which instar, since all are wild caught. Thanks for the feedback, this helps!


It is not necessarily the adults, because 5th instar is considered mature but when they lose the ability to stick to glass it means they will not molt again before their life is over.

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## InvertebrateGuild (May 18, 2020)

Lucky123 said:


> With the chelicerae on juveniles it can be hard to see. Do you no what instar it is (how many molts is has had)? They generally live to molt about 5-6 times, in a span of 6 months to a year. For captive breed spiders it is easy to keep track but for wild caught ones I use the process of elimination. 5th instar is usually considered mature, on their last molt they lose the ability to stick to plastic/glass, so if it can still climb glass it is not senior, if it is still orange then that eliminates 5th instar, so it could be 1st 2nd 3rd or 4th. 1st would be really tiny (around 3mm), and 2nd would be about the size of a Salticus scenicus, 3rd would larger and closer to the size of an adult female Habronatus pyrithrix. 4th is close to adult size about the size of your pinky finger. I apologize if you don’t understand, I was just using some of the wild species of jumping spider that I see a lot. So hopefully this will help you rule out the maturity, front legs that are fuzzy and longer than the rest means a mature male, females will also get quite a bit fuzzier and generally the spots turn white, for most of their life they have iridescent chelicerae, but it is hard to notice until the fangs get big.


This is extremely helpful, thanks for sharing @Lucky123!


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